CLIN CHEM EXPLORER

Lipoproteins and Renal Function Test - Slide Show

2017-08-04T21:07:00.001-07:00

View the slide presentation HERE

LACTATE DEHYDROGENASE DETERMINATION QUESTIONS AND ANSWERS

2017-06-24T18:53:00.001-07:00

1.    Discuss the principle of the test.

LDH in the serum catalyzes the oxidation reduction of lactate to pyruvate, which is measured spectrophotometrically.

2.    Give the reasons why serum for LD determination cannot be refrigerated.

Because LD isoenzymes are thermolabile and are unstable at refrigerated temperatures. They would not be able to react accurately.

3.    Why should there be timed intervals in the addition of 0.1N HCL?

So that the acid could react properly with the LDH in the sample.

4.    In the experiment, why should the incubation period be done exactly in 5 minutes?

Because incomplete reaction would occur if it is less than 5 minutes and more products would be formed when prolonged more than 5 minutes. This is at specified temperature and conditions.

5.    Name sources of errors in this determination.

Hemolyzed serum increases result 100-150 X
Turbid, lipemic and icteric serum needs serum blanking for accuracy
Refrigerated blood samples lowers values
Prolonged or shortened incubation time at specified conditions could increase or decrease values respectively
Altered temperatures could either increase nor decrease values

Alkaline Phospatase (ALP) Review Questions and Answers

2017-06-23T18:25:00.006-07:00

1.    Discuss the principle of the test.

ALP catalyzes the hydrolysis of Paranitrophenylphosphate, which is colorless, to paranitrophenol, which is colored yellow, at 405 nanometers.

2.    Name differences between ALP and ACP

CATEGORY                  ALP                                                    ACP
pH                            Basic or alkaline                                acidic
Best specimen     Heparinized plasma (Calbreath)            Serum citrated plasma (Calbreath)
Tissue source    Same as ACP except for prostate,            more on bone
Clin. significance    Prostate, platelets, bone, liver, spleen, kidneys, erythrocytes
Diagnostic significance    Hepatobiliary and bone disorders    Prostatic carcinoma

3.    What is the reason for diluting serum if the absorbance is higher than 0.25

For more precise and accurate measurement of the concentration of the unknown.

4.    Why do we have to adjust the spectrophotometer to zero when we read unknown solutions?

To read out errors caused by the spectrophotometer and the reagent.

5.    What is the best sample for this determination?

Unhemolyzed, clear, non-icteric, non-lipemic serum

Questions and Answers on Clinical Enzymology (ACP)

2017-06-23T05:36:00.001-07:00

1. Discuss the principle of the most common principle of the ACP test.

ACP catalyzes the hydrolysis of Paranitrophenylphosphate, which is colorless, at an acidic pH, to paranitrophenol, which is colored yellow, at 450 to 470 nanometers.

2. Why do you have to utilize a specific wavelength in measuring ACP?

To be able to get the maximum reading of ACP in the sample.

3. What is the ideal specimen for the ACP determination?

Citrated blood is ideal, but for the determination performed in the lab, it is serum.

4. Name sources of errors for ACP test

Hemolyzed serum falsely increases values

Turbid and icteric serum need serum blanking for accuracy

Some reagents are photosensitive, exposure to light would decrease values

Prolonged or shortened incubation time would increase and decrease values respectively

Alkaline pH would decrease values

Altered temperatures could either increase or decrease values

Effects of Decreased Carbon Dioxide in Atmosphere

2017-06-04T23:18:00.001-07:00

Carbon dioxide is one of the gases that could cause global warming. This is because it prevents the reflection of the sun’s heat back into space.

Normally, carbon dioxide exists ideally in the atmosphere at 0.03%. The percentage continues to increase because of combustion and emissions caused by man. Carbon dioxide is essential to plants because they need carbon dioxide to survive.

If carbon dioxide levels in the atmosphere were reduced to half, these living things would be the first to be affected.

Effects of Decreased Carbon Dioxide

Environmental change

A drastic decrease of carbon dioxide in the atmosphere would cause environmental changes. Since carbon dioxide causes global warming, its reduction would cause changes in the temperature of the environment.

The climate would become colder because of the absence of the greenhouse effect, in which humidity or warmth stays in the earth’s environment. The atmosphere becomes more transparent, which would facilitate the escape of heat to space, leaving the atmosphere colder.

These environmental changes would affect every living thing existing in the ecosystem.

Plants would grow extinct

Plants undergo photosynthesis through sunlight and carbon dioxide, so without this important gas, plants would wither and grow extinct.

Even marine plants would be affected. Since plants are major sources of food, there would be scarcity of food for man and animals on land and at sea. The food chain would be disrupted; that could result to a complete reversal of the chain.

Man would then have only animals for food. This scenario would cause various problems to humans because of the major disadvantages of animal meat. Man needs a balanced diet to remain healthy and fit.

If plants grow extinct and animal meat is the only source of food for humans, it would shorten man’s life span.

Oceans would become more acidic

Decreased carbon dioxide in the atmosphere would make the ocean become more acidic. This is because bicarbonate, formed from the combination of carbon dioxide and water, is also decreased in concentrations.

Most carbon dioxide gases are dissolved in water to establish equilibrium with the atmosphere, through diffusion.

The ocean helps in eliminating the toxic carbon dioxide produced by combustion. Aside from the above-mentioned major effects caused by reduced carbon dioxide levels, there are minor effects resulting from the major occurrences.

These include: complete freezing of some continents because of cold temperatures, more glaciers formed from bodies of water, and other detrimental results caused by cold temperatures.

Any variation in the carbon dioxide that affects the ecosystem would have an effect on almost everything existing in that system.

SODIUM DETERMINATION (Albanese and Lein)

2016-04-16T05:47:00.001-07:00

I. Introduction

Sodium is the most abundant cation in the extra cellular fluid (ECF), represented 90% of all extracellular cation and largely determines the osmolality of the plasma. Active transport system at the cellular membrane maintain high Na+ levels in the ECF, where as K+ is concentrated with in the cell.
Changes in extracellular Na+ concentration result in increase or decreases in the osmolality of the ECF, which in turn, influence the distribution of body water. It is therefore related in regulation of water balance as well as blood volume in the body.

Normally, serum Na+ concentration varies between 136 and 145 mmol/L in healthy individuals. The normal daily intake of Na+ is 100-250 mmol. Ordinarily, the amount of Na+ loss is balance by the daily intake.

Determination of Na+ level is of vital key in the proper diagnosis and treatment of diseases associated with it.

A decrease in serum sodium level, termed as “hyponatremia” is usually seen in hypoadrenalism, potassium deficiency, diuretic use, ketonuria, salt-losing nephropathy, prolonged vomiting, diarrhea, renal failure, hepatic cirrhosis, congestion heart failure (CHF) and diabetic ketoacidosis.

Whereas, an increase in serum sodium level, termed as “hypernatremia” is seen in profuse sweating, severe burns, dehydration, malnutririon, edema, ascitis in chronic failure, uncontrolled diabetes, and nephritic syndrome.

II. Procedure/ Flowchart of the experiment
A.
Pipet out 0.1ml serum and place in a test tube
↓
Add 3ml base reagent followed by 3 drops of color reagent
↓
Mix thoroughly for 30sec. and let it stand for 30min. at room temperature
↓
Read at 550nm against a water blank
↓
Interpret results obtained

B.

Place 0.1 ml of unhemolyzed serum into 16X100 mm test tubes.
↓

Label tube as test serum standard.
↓

Add 2.5 ml of Sodium Base Reagent into the tubes.
↓

Place 3 gtt of Sodium Color Reagent.
↓

Mix well and read at 550 nm against a water blank.

III. Results and Discussion

Concentration of the unknown: 531.62 mmol/L

Normal range for serum specimen: 134-148 mmol/L

Interpretation: “Above normal range”

The interpretation of the result obtained was above normal range because it exceeds the maximum Na+ level that a normal adult could have.

IV. Intrinsic and Extrinsic factors

The probable sources of errors are:

- contaminated tubes or cuvets

-          contaminated serum
-          ineffective reagent
-         under/ over centrifugation
-          prolonged standing of specimen
-          misreading of result by spectrophotometer

Chemical Structure of Seawater

2015-08-11T01:41:00.000-07:00

Seawater differs in chemical structure from plain water because of additional components that are present. Just by tasting, you would know that seawater is briny and contains salts that are not found in your ordinary drinking water. What is the chemical structure of seawater that makes it different?

1. Seawater has salts

Seawater has an average salt content of approximately 35 grams for every liter of seawater or 3.5% salt content. The salt includes calcium (Ca++), potassium (K+), chloride (Cl-), sodium (Na+), sulfate (SO4++), and magnesium (Mg++).

Sodium and chloride constitute majority of the seawater salts.
This chemical structure allows salinity of seawater. The salinity of seawater is constant and measuring one major salt allows representation of the other concentrations.

2. Seawater is denser than fresh water

The density of pure water is 1.00 grams per milliliter at specified temperatures. Seawater is denser, which is 1.025 grams per milliliter. The salt content of seawater makes it denser.

3. Seawater has a pH of 7.5 to 8.4

Pure water has a neutral pH at 7, but seawater
is more alkaline with pH range of 7.5 to 8.4. This is due to the presence of additional chemical components not found in fresh water.

4. Seawater has traces of other chemicals

Aside from the salts mentioned, seawater also has smaller amounts of strontium (Sr), bicarbonate (HCO3), bromide (Br), borate (BO3), and fluoride (F). There are still various chemicals present in sea water depending on its location and depth.

The aforementioned chemical structure of seawater enables measurement of distances based on sound which travels through the seawater’s components. These chemical components make seawater different from fresh water, pure water or river water.

The chemical components and salinity of water also prevents it from becoming potable or drinkable. The salt content of seawater could aggravate an existing condition of hypertension and cardiovascular conditions because the increased concentration of salt in the blood will influence the amount of water inside the cell.

The increase of sodium will promote osmosis, which will eventually drain the cells of water. The dehydration of the cells can cause heart conditions like arrhythmia.

It is great to know the seawater’s chemical structure so that you will know why seawater is not advisable to drink and to hydrate the body with. Knowing this basic fact would also allow you to keep abreast of simple scientific information that are essential for your health and well-being.

Renal Function Test: BUA, BUN and Creatinine

2015-07-26T06:23:00.002-07:00

RENAL FUNCTION TEST (RFT)

The major function of the kidneys is to eliminate waste products from the body and reabsorbed the substances essential for body function. When the kidneys’ functions are impaired, one or both processes are altered.

Image credit: Allfeline.on.com

Measurements of the ability of the kidneys to carry out their major processes provide vital data in knowing whether they’re normally functioning or not.

To know whether a kidney functions correctly we may perform different tests such as, test for Blood Urea Nitrogen (BUN), Creatinine and Blood Uric Acid (BUA).

CREATININE

Creatinine is used to diagnose impaired renal function.

This test measures the amount of creatinine in the blood. Creatinine is a catabolic product of creatinine phosphate, which is used in skeletal muscle contraction.

The daily production of creatine and subsequently creatinine depends on muscle mass, which fluctuates very little.

Creatinine, as BUN, is excreted entirely by kidneys and therefore is directly proportional to renal excretory function. Thus, with normal renal excretory function, the serum creatinine level should remain constant and normal.

Only renal disorders such as glomerulonephritis, pyelonephritis, acute tubular necrosis, and urinary obstruction, will cause an abnormal elevation in creatinine.

There are slight increases in creatinine levels after meals, especially after ingestion of large quantities of meat. Furthermore, there may be some diurnal variation in cr.

The serum creatinine test, as with the BUN, is used to diagnose impaired renal function. Unlike BUN, however, the creatinine level is affected minimally by hepatic function.

The serum creatinine level has much the same significance as the BUN level but tends to rise later. Therefore elevations in creatinine suggest chronicity of the disease process.

In general, a doubling of creatinine suggests a 50% reduction in the glomerular filtration rate. The creatinine level is interpreted in conjunction with the BUN.

NORMAL VALUES:

v ELDERLY decrease in muscle mass may cause decreased values

v ADULT

FEMALE 0.5-1.1 mg/dL or 44-97 umol/L

MALE 0.6-1.2 mg/dL or 53-106 umol/L

v ADOLECENT 0.5-1.0 mg/dL

v CHILD 0.3-0.7 mg/dL

v INFANT 0.2-0.2 mg/dL

v NEWBORN 0.3-1.2 mg/dL

INTERFERING FACTORS

v A high diet in meat content can cause transient elevations of serum creatinine.

v Drugs may increase creatinine values include aminoglycoside (e.g. gentamicin), cimetidine, heavy-metal chemotherapeutic agents (e.g. cisplatin), and other nephrotoxic drugs such as cephalosporins (e.g. cefoxitin)

TEST RESULTS AND CLINICAL SIGNIFICANCE

LEVELS

Disease affecting renal function, such as glomerulonephritis, pyelonephritis, acute tubular necrosis, urinary tract obstruction, renal blood flow (e.g. shock, dehydration, congestive heart failure, atherosclerosis), diabetic nephropathy, nephritis. With these illnesses, renal function is impaired and creatinine levels rise.

Rhabdomyolysis. Injury of the skeletal muscle causes myoglobin to be released in the blood stream. Large amounts are nephrotoxic. Creatinine levels rise.

Acromegaly

Gigantisim

These diseases are associated with increased muscle mass, which causes the “normal” creatinine level to be high

LEVELS

Debilitation

Decreased muscle mass (e.g. muscular dystrophy, myasthenia gravis)

The diseases are associated with decreased muscle mass, which causes “normal” creatinine level to be low.

Potassium, the Major Intracellular Cation

2015-07-18T10:46:00.001-07:00

Potassium is the primary intracellular cation. It is also an integral part of the transmission of nerve impulses. It participates in the sodium-potassium pump in the body.

Unhemolyzed serum should be used because hemolysis will markedly increase the potassium values because potassium is present in large amounts inside the cell.

Clinical Significance

1. Hyperkalemia – increased concentration of potassium in the bloodstream. It’s found in the following conditions:

• Decreased renal excretion

• Acute or chronic renal failure

• Hypoaldosteronism

• Addison’s disease

• Diuretic

· Cellular shift

• Acidosis

• Muscle/cellular injury

• Chemotherapy

• Leukemia

• Hemolysis

Increased intake

Oral or IV potassium replacement therapy

- Artifactual

Sample hemolysis

Thrombocytosis

Prolonged tourniquet use of excessive fist clenching

2. Hypokalemia – decreased concentration of potassium in the blood stream, seen in the following conditions:

GI loss

- Vomiting

- Diarrhea

- Gastric suction

- Intestinal tumor

- Malabsorption

- Cancer therapy

- Large doses of laxatives

Normal values:

K = 3.5-5.3

• Plasma and serum: 3.4 – 5.0 mmol/L

• Urine: 25 -125 mmol/L

Outline of Methamphetamine

2015-06-24T06:13:00.000-07:00

Methamphetamine

 Class of drugs is sympathomimetic

 Has direct stimulant activity on the CNS and Myocardium

 It is widely used to treat obesity

 They are extensively abused by individuals who try to stay awake for long period of time

 the effects of Methamphetamine generally last 2-4 hours

 has a half-life of 9-24 hours in the body

 generally detectable in the urine for 3-5 days

 Confirmatory testing is performed using GCMS.

 the effects of Methamphetamine generally last 2-4 hours

 has a half-life of 9-24 hours in the body

 generally detectable in the urine for 3-5 days

 Confirmatory testing is performed using GCMS.

Screening Sample – Urine
Confirmatory Sample - Blood

Methods

1. Immunoassay Systems Screening procedure (Methamphetamine card test)

2. Liquid or gas chromatography

Precautions

-Adulterants, such as bleach or other strong oxidizing agents.

- Clean container w/o any preservatives

- Store the urine specimen at 2-8 degrees C or freeze urine specimen (-20degrees C) for longer storage

Solving the weight of substances needed to produce molar and normal solutions

2015-06-19T22:19:00.003-07:00

To be able to solve the weight of substances needed to prepare certain molar and normal solutions, you can use the general formulas:

For Normal solutions

N = GEW/L of solution

GEW = W/MW/v

N = (W/MW/v)/L of solution

Where:

GEW = Gram Equivalent Weight

L = Liter

W = weight in grams of substance

EW = Equivalent Weight

MW = Molecular Weight

v = valence

The short cut formula is:

W = DN X DV X EW (MW/v)

Where:

DN = Desired Normality

DV = Desired Volume
EW = Equivalent Weight

MW = Molecular weight

v = valence

Here’s a sample problem.

How much CaCl2 will you need in preparing 500 mL of a 0.5 N solution?

W = DN X DV X EW (MW/v)

W = 0.5 X 0.5 X (111/2)

W = 13.875 grams of CaCl2

To prepare the 0.5 N CaCl2 solution:

Weigh 13.875 grams of CaCl2 and dilute it to 500 mL of solution in a volumetric flask. You can first dispense 250 ml of the distilled water to the flask, dissolve the 13.875 CaCl2, and then add the diluent up to the 500 mL mark of the volumetric flask.

Take note of the following:

1. Volume must always be converted to liters when using this formula, or if you don’t want to convert, divide your answer by 1,000.

2. The powder must not be added to 500 ml or 0.5 L but diluted TO 500 mL to in a volumetric flask to get the exact volume. The resulting volume in your 500 ml flask after dissolving the CacL2 must not be more or less than 500 ml. This will ensure accuracy of your measured solution.

For Molar solutions

M = GMW/L of solution

GMW = Weight/MW

M = (W/MW)/L of solution

Where:

GMW = Gram Molecular Weight

L = Liter

W = weight in grams of substance

MW = Molecular Weight

v = valence

Hence for Molar solutions the formula is:

W = DM X DV X MW

Where:

DM = Desired Molarity
DV = Desired Volume
MW= Molecular Weight

If you're given the same data but asked to solve for the molarity this is the formula and substitution:

Here’s a sample problem.

How much CaCl2 will you need in preparing 500 mL of a 0.5 M solution?

W = DN X DV X MW

W = 0.5 X 0.5 X 111

W = 27.75 grams of CaCl2

The only difference from the Normal solution is the absence of valence.

To prepare the 0.5 M CaCl2 solution:

Weigh 27.75 grams of CaCl2 and dilute it to 500 mL of solution in a volumetric flask.

You can first dispense 250 ml of the distilled water in the flask, dissolve the 27.75 CaCl2, and then add the diluent up to the 500 mL mark of the volumetric flask.

Clinical Chemistry 1 - Lipids and Its Major Functions, Fatty Acids Powerpoint Presentation

2015-06-13T21:02:00.001-07:00

Lipids are unique from other substances in the blood because they are non polar and insoluble in water, but soluble in organic solvents.

Lipids (fats) in food are more difficult to digest than proteins and carbohydrates. Lipids are present in the body through various forms, such as triglyceride (storage form of lipid), phospholipid (important parts of biomembranes), cholesterol (important component of steroid hormones),fatty acids (the simplest forms of lipids).

Lipids have crucial functions in the body that include the following:

1. Acts as a body insulator. So, it's true Virginia, that when you're fat, you have more "heat insulators" in your body, hence, will feel less susceptible to the cold weather,

2. Acts as biomembranes (protector) of vital organs, such as the brain and the lungs.

3. Acts as an enzyme in the form of prostaglandin.

4. Acts as the basic component of steroid hormones.

5. Acts as carrier proteins for non-polar substances.

6. Acts as a source of energy when there's a dysfunction of carbohydrate being converted to energy.

Below is a slide presentation submitted by a previous student that you can read to let you understand more about lipids.

CC1 Lipids Lecture ppt from JenaIsle

Review on Lab Instrumentation, Clinical Chemistry 1

2015-06-11T23:42:00.001-07:00

Spectrophotometer

An instrument used for measuring the transmission or reflection of light by comparing various wavelengths of the light. It also makes use of the Beer-Lambert’s principle which is “Light transmitted is inversely proportional to the concentration, while the absorbance is directly proportional to it.”

Some of the precautions in this test:

1. Never brush cuvettes because it will lead to scratches and give inaccurate results

2. Use rather a clean soft cloth to wipe the cells before reading it

3. Ideal amount of the sample is ¾ full so that the light will strike the given sample and not the empty space.

4. Let the machine be warmed up first for about 10-15 min before use, so that fluctuation is avoided.

There are four essential parts of a spectrophotometer

1. Light source

2. Monochromator or filter

3. Sample cell with holder

4. Detector

Turbidimetry

- The determination of the quantity of insoluble suspended matter in a liquid by measuring the loss of intensity of light in the direction of propagation of the incident beam, with reference to a standard solution

Gravimetry

- Gravimetric methods of analysis are used where weights of reactants and products of chemical reactions are reproducible, stable and reflect the presence of constituents which are important in the establishment of identity.

- Two important methods deal with the trapping and weighing of products in the solid and gaseous phases.

Osmometry

- Measurement of the amount of osmotic pressure that a particular solution exerts

- Can be vapor pressure osmometry, freezing point depression osmometry or membrane osmometry

Emission Flame Photometry

A type of flame photometry in which molecules in a flame are volatilised to generate free atoms that are excited to higher energy levels. When these atoms return to the ground state, they produce a characteristic emission spectrum. These typically use a low-temperature, air-gas, laminar flame burner which is inherently subject to drift and therefore lithium (Li), which is not a normal serum constituent, is excited as a known added constituent to "standardize" the results despite the drifting of the flame output. This approach does not permit addition of Ca as a third determined constituent as the emission of the Ca at serum levels in the low-temperature flame is below measurable intensity; furthermore the Li would interfere optically with the Ca determination.

Atomic Absorption Spectrophotometry

Atomic Absorption Spectrophotometry is the measurement of the concentration of an element in a given sample. This technique can be done in three ways: Flame type, Electrothermal type, and Color Vapor type. In the flame type, gas and combustible substance are used to ignite the mixture of gases.

The second type which is electrothermal makes use of electric current and slit width. On the other hand is the cold vapor method wherein a reducing agent is added and vaporized.

Volumetry

Volumetry is t he measurement of volumes of liquids, solids, and gas.

-the quantitative analysis of an unknown chemical solution by determining the amount of reagent of known concentration necessary to effect a reaction in a known volume of the solution

Chromatography

It is a broad range of physical methods used to separate and or to analyze complex mixtures. The components to be separated are distributed between two phases: a stationary phase bed and a mobile phase which percolates through the stationary bed.

Thin Layer Chromatography

TLC is a simple, quick, and inexpensive procedure that gives the chemist a quick answer as to how many components are in a mixture. TLC is also used to support the identity of a compound in a mixture when the R_f of a compound is compared with the R_f of a known compound (preferably both run on the same TLC plate).

A TLC plate is a sheet of glass, metal, or plastic which is coated with a thin layer of a solid adsorbent (usually silica or alumina). A small amount of the mixture to be analyzed is spotted near the bottom of this plate. The TLC plate is then placed in a shallow pool of a solvent in a developing chamber so that only the very bottom of the plate is in the liquid. This liquid, or the eluent, is the mobile phase, and it slowly rises up the TLC plate by capillary action.

B. Gas chromatography

specifically gas-liquid chromatography - involves a sample being vaporized and injected onto the head of the chromatographic column. The sample is transported through the column by the flow of inert, gaseous mobile phase. The column itself contains a liquid stationary phase which is adsorbed onto the surface of an inert solid.

C. ‘High Performance Chromatography

High-performance liquid chromatography (HPLC) is a form of liquid chromatography to separate compounds that are dissolved in solution. HPLC instruments consist of a reservoir of mobile phase, a pump, an injector, a separation column, and a detector. Compounds are separated by injecting a plug of the sample mixture onto the column. The different components in the mixture pass through the column at different rates due to differences in their partitioning behavior between the mobile liquid phase and the stationary phase.

Electrophoresis

Electrophoresis is a separations technique that is based on the mobility of ions in an electric field. Positively charged ions migrate towards a negative electrode and negatively-charged ions migrate toward a positive electrode. For safety reasons one electrode is usually at ground and the other is biased positively or negatively. Ions have different migration rates depending on their total charge, size, and shape, and can therefore be separated.

Instrumentation

An electrode apparatus consists of a high-voltage supply, electrodes, buffer, and a support for the buffer such as filter paper, cellulose acetate strips, polyacrylamide gel, or a capillary tube. Open capillary tubes are used for many types of samples and the other supports are usually used for biological samples such as protein mixtures or DNA fragments. After a separation is completed the support is stained to visualize the separated components.

Resolution can be greatly improved using isoelectric focusing. In this technique the support gel maintains a pH gradient. As a protein migrates down the gel, it reaches a pH that is equal to its isoelectric point. At this pH the protein is neutral and no longer migrates, i.e., it is focused into a sharp band on the gel.

Laboratory Instrumentation in Clinical Chemistry a Powerpoint Presentation

2015-06-06T09:43:00.000-07:00

A powerpoint presentation in Clinical Chemistry about laboratory instrumentation. View the images to help you become familiar with these instruments. You can also print the lecture version as your guide on the topic. A quiz is given at the end of the powerpoint to determine if you have learned something from the presentation. Enjoy the slide and good luck with your clinical chemistry class.

Why Serum is the best Specimen in most Clinical Chemistry Laboratory Tests

2015-03-19T05:11:00.001-07:00

Serum is the supernatant fluid when clotted blood has been centrifuged. It is the best specimen for most clinical chemistry laboratory tests because of its specific characteristics. Here are the reasons why serum is the best specimen.

*Serum has less protein

When blood clots, one of the proteins - fibrinogen - takes part in the clotting process; thereby removing it from the serum. The absence of fibrinogen would make the supernatant clearer, while in plasma, since the blood does not clot, the fibrinogen remains in the supernatant and could add to the turbidity of the plasma.

*Serum has no anticoagulant

Since serum does not have an anticoagulant, there are no other substances that could interact with your test. There are potential interferences coming from anticoagulants with certain tests.

One example is the interference of the anticoagulant ethylene diaminetetraacetic acid (EDTA) in the laboratory determination of calcium ions. EDTA chelates calcium; hence, decreasing inaccurately the concentration of calcium in the sample.

The presence of an anticoagulant could also dilute the specimen and unreliably lower the concentration of the substance being analyzed.

*Most reagents are more compatible with serum

The optimum reaction of the reagent with the substance in the blood is very important to produce reliable results; results that are precise and accurate simultaneously.

When a result is precise, it means that you get almost the same results repeatedly. Accuracy on the other hand, means obtaining values close to the “true value.”

When a result or method is reliable, then you are certain of the results because you know they could be depended on. Laboratory results are the data that doctors could base their diagnosis on.

Together with the history of the patient, the other diagnostic results, doctors could now come up with a conclusive diagnosis.

*Serum can be more stable than plasma with certain substances

Some research like the study done by O'Keane and Cunningham proved that serum is more stable for other substances than plasma.

This is most especially for serum extracted with a separator gel. Gel tubes proved to be stable for creatinine, potassium, and urea than in plasma.

This would specify that gel tubes are more stable that plain serum tubes. These are the reasons why serum is considered the best specimen.

This does not indicate though, that the other blood specimens could not be used. There are certain tests, which require, specifically a plasma sample or a whole blood sample.

Knowing what these tests are would help a lot in coming up with reliable results and a correct diagnosis by the doctor.

How Ethanol Production Wastes Corn

2015-03-18T18:52:00.000-07:00

Ethanol is a type of alcohol that can be used as a motor fuel or fuel additive. It is also present in alcoholic beverages, scents, and is sometimes used as a recreational drug. Previous studies revealed that ethanol can be produced from lignocellulosic biomass of corn stovers.

The process was originally considered as promising. The use of supposedly “useless” agricultural by-products, like corn stovers, to produce an alternative source of motor fuel was a sensational discovery, considering the scarcity of gasoline available for worldwide consumption.

Further studies revealed however, that the production of ethanol from corn stover has been found out to waste corn because of the following reasons:

1. Ethanol combustion produces 2.14 times as much ground level ozone than gasoline The data was presented by the Clean Fuels Report about the comparison of fuel emissions between ethanol and gasoline.

The report further stated that ethanol contributes 1.7 to the pollution caused by smog, while gasoline contributes only 1.0.

2. Prices of corn increased Because of the increase need in the production of ethanol from corn stovers, the price of corn has actually increased in the market.

The reduced supply of corn as staple food has prompted the increase in its price, while the total cost of producing ethanol from corn has also increased. Either way, the consumers do not benefit in the end.

3. Processing of corn stovers to ethanol is costly Contrary to previous assumptions, the production of a liter of ethanol is more costly than 1 liter of gasoline.

This is because the process of hydrolysis needs large amounts of water, needs more money to deal with carbon emissions, and requires more energy for its processing. The sugars present in the corn stovers have also to undergo fermentation before they are converted to ethanol, adding more production costs.

4. Environmental friendliness of ethanol is in question Ethanol from corn is not altogether environmental friendly because it produces acetaldehyde and formaldehyde which are considered as harmful substances. These substances can cause cancer when persons are exposed continuously for a long period of time. They pollute the environment through the water that you drink, the air you breathe and the substances or food that you take in.

The US national budget for the production of ethanol from corn was recently slashed last June, 2011 by the US Senate because of some of these aforementioned reasons.

The corn prices have dropped since then, and with this development, the corn industry would go back to being one of the primary sources of food for humans and animals and not as a source of biofuel.

The Analysis of Blood Gas

2014-07-19T05:42:00.001-07:00

Blood gas analysis (BGA) is also known as arterial blood gas determination (ABG), and is considered a special test in the clinical laboratory. The commonly assayed parameters are partial pressure carbon dioxide (pCO2), hydrogen ion concentration (pH) and bicarbonate (HCO3). The determination of these substances helps in the evaluation of the acid-base status of a patient.

Image credit: Lara Enriquez

The following are certain precautions observed by medical technologists in the extraction of arterial blood for blood gas analysis.

1. The best specimen is arterial blood.

This is because arterial blood is more homogenous than venous blood. The blood could be collected in the following common arterial sites: the radial artery, the brachial artery, the femoral artery and the scalp artery.

The most ideal anticoagulant is dry heparin, and the preferable syringe is a glass syringe. Recently, new receptacles are manufactured which are specifically for BGA.

2. Collect the specimen anaerobically (without air).

Your specimen should be covered at all times to prevent the escape of carbon dioxide to the air. It should be transported immediately to the testing laboratory. If it is left uncovered, unreliable results will be obtained which will lead to a wrong diagnosis by the Clinician/physician.

3. Preserve in crushed ice, if not tested immediately.

The low temperature has to be maintained. An increase in temperature would cause the gas to evaporate. It must also be preserved properly to obtain reliable results, aside from making sure that it is covered.

The body naturally maintains a state of balance called homeostasis. In the case of blood pH, this is done by the lungs and the kidneys which act as compensatory organs for one another. When the lungs are dysfunctional just like in respiratory diseases (emphysema, TB, chronic bronchitis, etc), the kidneys respond by excreting or retaining bicarbonate (HCO3).

On the other hand, when the kidneys are dysfunctional, the lung will respond by the increase retention or excretion of carbon dioxide (CO2). Through these physiologic processes, the critical pH (acidity and alkalinity) of blood is maintained at 7.35 to 7.45. Any slight variation from this pH, whether an increase or decrease, will lead to coma and eventually death. It is therefore imperative that the body maintains this slightly alkaline pH of blood for good health.

The following are acid-base conditions and the corresponding compensatory mechanisms :

Values : pH - decreased , PCO2 normal, HCO3 - decreased

Condition - metabolic acidosis

Compensatory mechanism - hyperventilation , increase excretion of CO2

decreased retention of CO2

Values: pH increased, HCO3 - increased , PCO2-normal

Condition - metabolic alkalosis

Compensatory mechanism - hypoventilation, decreased excretion of CO2

adparams.getadspec('c_billboard1');

increased retention of CO2

Values : pH- increased , PCO2 - decreased , HCO3 -normal

Condition - respiratory alkalosis

Compensatory mechanism : increased retention of HCO3

decreased excretion of H+

Values: pH-decreased , PCO2 -increased, HCO3 -normal

Condition: respiratory acidosis

Compensatory mechanism : increased retention of HCO3,

increased excretion of H+

Clinical laboratory scientists or medical technologists solve for the pH of blood making use of the

Henderson-Hasselbalch Equation: (H & H equation). The formula for this is:

pH = 6.1 + log (HCO3)/DCO2

HCO = TCO2-DCO2

DCO2 = PCO2 X 0.031

Where: pH =indicates the acidity or alkalinity of a solution (hydrogen ion concentration.

HCO3 - bicarbonate

DCO2 - dissolved carbon dioxide

TCO2 - total carbon dioxide

Normal values are:

pH = 7.35-7.45

HCO3 = 22 - 26 mmol/L

PCO2 = 35 - 35 mmHg

TCO2 = 23-27 mmol/L

Arterial blood gas has very important clinical significances. It is crucial that the Medical Technologists know the precautions and perform the determination accurately. A well performed ABG signifies a patient well served.

This was published by http://voices.yahoo.com/the-analysis-blood-gas-2482704.html?cat=5.

Reference:

Calbreath, Donald F. Fundamentals of Clinical Chemistry

CLINICAL CHEMISTRY 3 FINAL EXAMS - TABLE OF SPECIFICATIONS

2014-05-21T23:17:00.001-07:00

CLINICAL CHEMISTRY 3 FINAL EXAMS - TABLE OF SPECIFICATIONS

TOPIC	PERCENT (%)	ITEMS

ENDOCRINOLOGY	48	55
TOXICOLOGY	31	35
DRUG TESTING	21	25
TOTAL	100%	115	Grand Total= 130 items
TRANSCRIPTION		15

TRANSCRIPTION = 15 POINTS FOR A GRAND TOTAL OF 130.

Please Bring:

Calculator (no borrowing of calculators)

Blue book ( 1 pc.)

Permits

Pencil lead 2 (2 pcs) for SCANTRON answer sheet

Type of test

1. MULTIPLE CHOICE(115 pts), which includes:

Matching type (3 pts.)

Problem solving (3 pts)

Case analysis (7 pts.)

II. TRANSCRIPTION (15 pts.)

TABLE OF SPECIFICATIONS - CLINICAL CHEMISTRY 3- LECTURE

2014-04-30T23:01:00.000-07:00

CLINICAL CHEMISTRY 3- LECTURE

MIDTERM EXAMS, SUMMER AY: 2013-2014

TABLE OF SPECIFICATIONS

TOPIC	(%)	MC	MT	PS	CA	ID	TRANS	TOTAL ITEMS
ENDOCRINOLOGY	72	25	24	5	20	7	9	90
TOXICOLOGY	28	10	6	10		3	6	35

TOTAL	100%	35	30	15	20	10	15	125 GRAND TOTAL

LEGEND:

ID- IDENTIFICATION

MC – MULTIPLE CHOICE

MT- MATCHING TYPE

PS – PROBLEM SOLVING

CA - CASE ANALYSIS

TRANS - TRANSCRIPTION

WHAT TO BRING:

1. BLACK OR BLUE BALLPENS (2)

2. BLUEBOOK #1

3. CALCULATORS (BORROWING OF CALCULATORS IS NOT ALLOWED)

4. PERMITS

PLEASE COME IN COMPLETE UNIFORM.

FYI

/VBG

Winners of Edublogging CC3 2012-2013

2014-04-20T09:16:00.000-07:00

The prizes are not much because we do not have donors. Kaya lollipop na lang. Claim your prizes tomorrow from me at the ground floor, room of Sir Nino. Congratulations:

First Prize:

KIMBERLY MIRANDA - CCBLOGNOTES 8d-A - http://kimpressionist.blogspot.com/ 37.16% (123 votes)

Second Prize:

BLESSY CONTRERAS - CCBLOGNOTES 8b-A -http://clinchem8ba.blogspot.com/2013/04/adrenaline-rushsuperhuman.html 23.26% (77 votes)

Third Prize:

BETINA - CCBLOGNOTES 10-d-C - http://mcbetina17.blogspot.com/ 7.55% (25 votes)

TO VIEW ACTUAL RESULTS, CLICK HERE.

TABLE OF SPECIFICATIONS CLINICAL CHEMISTRY 2 – FINAL EXAMS

2014-03-18T23:42:00.000-07:00

TABLE OF SPECIFICATIONS

CLINICAL CHEMISTRY 2 – FINAL EXAMS

TOPIC	%	ITEMS
LFT	10.37	14
AUTOMATION	11.11	15
BGA	11.11	15
ELECTROLYTES	10.37	14
ENZYMES	57.03	77
SUB TOTAL	100%	135

TRANSCRIPTION		15

GRAND TOTAL		150

TYPES OF QUESTIONS:

1. MULTIPLE CHOICE

2. PROBLEM SOLVING (AS PART OF MULTIPLE CHOICE)

3. CASE ANALYSIS (AS PART OF MULTIPLE CHOICE)

4. MATCHING TYPE (AS PART OF MULTIPLE CHOICE)

5. TRANSCRIPTION

LABORATORY: -ALL EXPERIMENTS

PLEASE BRING:

1. PERMITS

2. CALCULATORS (NO CELL PHONES, AND NO BORROWING)

3. PENS (BLACK OR BLUE)

4. GREEN MARKER

5. 1. BLUEBOOK

COME IN COMPLETE UNIFORM.

FYI AND GUIDANCE

CC2 INSTRUCTORS

YOU CAN FIND REVIEW QUESTIONS AT CLIN CHEM REVIEWER.

CC2 Table of Specifications for Midterms

2014-02-03T00:33:00.002-08:00

CLINICAL CHEMISTRY 2- LECTURE- MIDTERMS AY: 2013-2014

TABLE OF SPECIFICATIONS FOR MIDTERMS

TOPIC	(%)	TOTAL ITEMS
LFT	25	30
AUTOMATION	25	30
ELECTROLYTES	20	24
BLOOD GAS ANALYSIS	30	36
TOTAL TRANSCRIPTION (15 pts.)	100%	120 135-GRAND TOTAL

WHAT TO BRING:

1. BLACK OR BLUE BALLPENS

2. LEAD 2 PENCILS

3. CALCULATORS (BORROWING OF CALCULATORS IS NOT ALLOWED)

4. PERMITS

PLEASE COME IN COMPLETE UNIFORM.

FOR CC2 LABORATORY- ALL EXPERIMENTS UP TO ENZYME TEST PERFORMED .

FYI

/VBG

Blood Gas Analysis Review Questions for Clinical Chemistry 2 Midterm Exams

2014-02-02T23:54:00.001-08:00

CLINICAL CHEMISTRY 2

NAME: ___________________________________________________YEAR/SEC: __________
DATE:__________________________________________

I.    MULTIPLE CHOICE ( I PT. EACH)
SHADE THE BOX THAT CORRESPONDS TO THE LETTER OF YOUR CHOICE (Best answer) IN THE ANSWER SHEET PROVIDED.

1.    The most common specimen for blood gas analysis is:
a.    Plasma                c. whole blood     e. arterial blood
b.    Serum                d. buffy coat

CASE ANALYSIS

The following lab results were obtained from a 50-year old male patient, complaining of persistent diarrhea for 3 days and rapid respiration : Laboratory results were:
                pH = 7.21
                                                pCO2 = 19 mm Hg
                                                PO2 = 96 mm Hg
                                                Total Bilirubin – 25 mg/dL
                                                HCO3 = 7 mmol/L
                                                SO2 = 96 %
                                                 K Injection:

2.    What is the patient’s acid-base status?
a.    Respiratory acidosis
b.    Respiratory alkalosis
c.    Metabolic acidosis
d.    Metabolic alkalosis
e.    all of the above
f.    none of the above

3.    Based on the laboratory results given in question no.2. Why is the HCO3 level so low?
a.    Because of rapid respiration
b.    Because of persistent diarrhea
c.    Because it compensates the respiratory aspect
d.    A & C
e.    C & D
f.    None of the above
g.    All of the above

4.    Why does the patient have rapid respiration?
a.    To restore normal pH
b.    To decrease pCO2
c.    To restore 20:1 HCO3 to H2CO3 ratio
d.    A & C only
e.    All of the above
f.    none of the above

CHOICES FOR NOS. 5-onwards

EXISTING CONDITION:

A.    UNCOMPENSATED RESPIRATORY ACIDOSIS
B.    UNCOMPENSATED RESPIRTATORY ALKALOSIS
C.    UNCOMPENSATED METABOLIC ACIDOSIS
D.    UNCOMPENSATED METABOLIC ALKALOSIS
E.    PARTIALLY COMPENSATED RESPIRATORY ACIDOSIS
F.    PARTIALLY COMPENSATED RESPIRATORY ALKALOSIS
G.    PARTIALLY COMPENSATED METABOLIC ACIDOSIS
H.    PARTIALLY COMPENSATED METABOLIC ALKALOSIS
I.       FULLY COMPENSATED RESPIRATORY ACIDOSIS
J.       FULLY COMPENSATED RESPIRATORY ALKALOSIS
K.    FULLY COMPENSATED METABOLIC ACIDOSIS
L.    FULLY COMPENSATED METABOLIC ALKALOSIS
M.    NONE OF THE ABOVE

5.    pH= 7.36, HCO3= 23 mmol/L, pCO2= 45 mmHg=M
6.    pH= 7.55, HCO3 = 28 mmol/L, pCO2 = 59 mmHg=H
7.    pH= 7.15, HCO3 = 9 mmol/L, pCO2 = 25 mmHg=G
8.    pH = 7.8, HCO3 = 18 mmol/L, pCO2 = 30 mmHg=F
9.    pH= 7.48, TCO2= 39 mmol/L, pCO2 = 28 mmHg=H
10.    pH= 7.50, HCO3= 25 mmol/L, pCO2 = 18 mmHg=B

CHOICES FOR 66 TO 70

COMPENSATORY MECHANISM:

INDICATE WITH AN ARROW HOW THE SPECIFIC SUBSTANCES WOULD COMPENSATE IN THE FOLLOWING EXISTING CONDITIONS:

11.    FEVER –RESULTS TO METABOLIC ACIDOSIS – LUNGS WOULD COM[PENSATE- PCO2 INC.EXCRETION, H+ INCREASED EXCRETION.
12.    SWEATING –SAME AS NO. 11
13.    ANXIETY –RESULTS TO HYPERVENTILATION CAUSING RESPIRATORY ALKALOSIS- KIDNEYS WOULD COMPENSATE BY DECREASING HCO3, H+ RETENTION AND INCREASING EXCRETION,
14.    PHYSICAL EXERTION –SAME AS NO. 13
15.    COPD – MOST CAUSE HYPOVENTILATION CAUSING RESPIRATORY ACIDOSIS, KIDNEYS WOULD COMPENSATE BY INCREASING RETENTION OF HCO3 AND DECREASING ITS EXCRETION, H+ INCREASED EXCRETION.

16.    RESULTS OF LAB TESTS:
•    pCO2= 53 mm Hg
•    O2 Saturation: 79%
•    HCO3= 29 mmol/L

QUESTIONS:
•    1. WHAT IS THE PH?-7.36
•    2. IDENTIFY THE CONDITION. DEFEND YOUR ANSWER. -REFER TO NOTES
•    3. WHAT IS THE BODY’S COMPENSATORY MECHANISM? -REFER TO NOTES
•    4. WHAT ADDITIONAL TEST COULD YOU PERFORM? - DELTA CHECK, ELECTROLYTES, 5 COMMON PARAMETERS (BUA,TAG,CREA, FBS, CHOLE), CBC.

ANSWER: FULLY COMPENSATED RESPIRATORY ACIDOSIS.

17.    RESULTS OF LAB TESTS:
TCO2= 27 mmol/L
PCO2= 45 mmHg

QUESTIONS:
•    1. WHAT IS THE PH?=7.38
•    2. IDENTIFY THE CONDITION. DEFEND YOUR ANSWER. -ALL VALUES ARE NORMAL
•    3. WHAT IS THE BODY’S COMPENSATORY MECHANISM? - N/A
•    4. WHAT ADDITIONAL TEST COULD YOU PERFORM? - IF PATIENT FEELS UNWELL, RECOMMEND EXECUTIVE LAB TESTS. (ALL)

ANSWER: NORMAL PATIENT

18.    LABORATORY RESULTS:
pH = 7.27
pCO2= 55 mm Hg
pO2= 50 mm Hg
Hgb = 13.5 g/L
O2 Saturation: 79%
HCO3= 28 mmol/L

QUESTIONS:

1. IDENTIFY THE CONDITION. –PARTIALLY COMPENSATED RESPIRATORY ACIDOSIS W/T HYPOXIA
2. DEFEND YOUR ANSWER.

19.    LABORATORY RESULTS:
pH = 7.27
pCO2= 58 mm Hg
pO2= 100 mm Hg
Hgb = 13 g/L
O2 Saturation: 98%
HCO3= 23 mmol/L

QUESTIONS:
1. IDENTIFY THE CONDITION. –UNCOMPENSATED RESPIRATORY ACIDOSIS
2. DEFEND YOUR ANSWER-

20.    LABORATORY RESULTS:
pH = 7.10
pCO2= 40 mm Hg
pO2= 91 mm Hg
Hgb = 14 g/L
O2 Saturation: 95%
HCO3= 13 mmol/L

QUESTIONS:
1. IDENTIFY THE CONDITION. - UNCOMPENSATED METABOLIC ACIDOSIS
2. DEFEND YOUR ANSWER-REFER TO NOTES

FOR MORE REVIEW QUESTIONS, YOU CAN VISIT CLIN CHEM REVIEWER TO BROWSE MORE QUESTIONS.

CLINICAL CHEMISTRY 2- LECTURE AY: 2013-2014-Table of Specifications for Prelims

2013-12-14T22:35:00.000-08:00

CLINICAL CHEMISTRY 2- LECTURE AY: 2013-2014

TABLE OF SPECIFICATIONS

TOPIC	(%)	MC	PS	CA	IDENTIF.	ESSAY	TOTAL ITEMS
LFT	37	35	5	5	3	5	53
AUTOMATION	30	35			4	5	44
ELECTROLYTES	33	30		10	3	5	48
TOTAL TRANSCRIPTION (15 pts.)	100%	100	5	15	10	15	145 160-GRAND TOTAL

LEGEND:

IDENTIFICATION

WHAT TO BRING:

1. BLACK OR BLUE BALLPENS

2. LINEAR GRAPHING PAPER

3. LEAD 2 PENCILS

4. CALCULATORS (BORROWING OF CALCULATORS IS NOT ALLOWED)

5. PERMITS

PLEASE COME IN COMPLETE UNIFORM.

FOR CC2 LABORATORY- ALL EXPERIMENTS (EXPTS. NO. 1 – EXPTS. NO. 2 )

FYI

/VBG

CLINICAL CHEMISTRY 2: GUIDELINES ORAL REPORTING ON AUTOMATION

2013-11-24T07:45:00.000-08:00

1.    SUBMISSION OF REPORTS (POWERPOINT AND WRITTEN) THE DAY BEFORE ORAL REPORTING.

2.    USE GREEN FOLDERS FOR WRITTEN REPORTS.

3.    THE WRITTEN REPORT SHOULD BE TYPEWRITTEN BUT IT SHOULD SUMMARIZE THE TOPIC USING YOUR OWN WORDS. AVOID COPY-PASTING.

4.    GRADING OF WRITTEN REPORTS WOULD DEPEND ON THE FOLLOWING CRITERIA:
4.1    COMPLETENESS OF CONTENT = 70 %
4.2    ORGANIZATION = 10%
4.3    PROMPT SUBMISSION = 10%
4.4    CREATIVENESS – 10%

5.    GRADING OF ORAL REPORTS WOULD DEPEND ON THE FOLLOWING CRITERIA:
5.1    COMPLETENESS OF CONTENT = 50 %
5.2    ORGANIZATION = 5%
5.3    PROMPT SUBMISSION = 5%
5.4    CREATIVENESS – 5%
5.5    PRESENTATION – 10%
5.6    ABILITY TO ANSWER QUESTIONS – 15%
5.7    ABILITY TO AROUSE INTEREST – 5 %
5.8    ABILITY TO EXPRESS IDEAS- 5%

6.    FOR GROUPS WITHOUT ASSIGNMENTS, PLEASE SEE CC2 INSTRUCTORS ON MONDAY.

PLEASE BE GUIDED ACCORDINGLY.