Clinical Chemistry (BOC)

The urinary excretion product measured as an indicator of epinephrine productin is:

vanillylmandelic acid

Which 2 conditions can 'physiologically' elevated serum alkaline phosphatase?

growth, third trimester of pregnancy

The T3 resin uptake test is a measure of:

binding capacity of thyroxine-binding globulin

During an evaluation of renal function, a patient had plasma cortisol determiniations in the morning after awakening and in the evening. Laboratory results indicated that the morning value was higher than the evening concentration. This is indicative of

a normal finding

In the liver, bilirubin is converted to:

bilirubin diglucuronide

The results listed on page 120 were obtained in a creatinine clearance evaluation: The creatinine clearance in mL/min is:

65

The electrophoretic pattern of plasma sample compared with a serum sample shows a:

sharp fibrinogen peak

The biuret reaction for the analysis of serum protein depends on the number of:

peptide bonds

Total iron-binding capacity measures the serum iron transporting capacity of:

transferrin

In the Jendrassik-Grof method for the determination of serum bilirubin concentration, quantitation is obtained by measuring the green color of:

azobilirubin

Absorbance (A) os a solution may be converted to percent transmittance (%T) using the formula:

A = 2 - log%T

Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are both elevated in what disease?

viral hepatitis

Calcium concentration in the serum is regulated by:

parathyroid hormone

What steroid is an adrenal cortical hormone?

corticosterone

Blood PCO2 may be measured by:

calculations of blood pH and total CO2 concentrations

In the potentiometric measurement of hydrogen ion concentration, reference electrodes that may be used include:

silver-silver chloride

In a spectrophotometer, light of a specific wavelength can be isolated from white light with a(n):

diffraction grating

The oslolality of a urine or serum specimen is measured by a change in the:

freezing point

Which of the following serum constituents is unstable if a specimen is left standing at room temperature for 8 hours before processing? cholesterol, triglyceride, creatinine, or glucose

glucose

A urine screening test for porphobilinogen is positive. The MOST likely disease state is:

acute porphyria attack

In electrophoretic analysis, buffers:

act as a carrier for ions

A condition in which erythrocyte protoporphyrin is increased is:

iron deficiency anemia

The stimulant that causes localized sweating for the sweat test is:

pilocarpine nitrate

In the sweat test, the sweating stimulant is introduced to the skin by application of:

an electric current

The formula for calculating serum osmolality that incorporates a correction for the water content of plasma is:

2Na + Glucose/20 + (BUN/3)

Osmolal gap is:

the difference between the calculated and measured osmolality values

Erroneous ammonia levels can be eliminated by all of the following EXCEPT: See page 124 for choices.

d. storing the specimen protected from light until the analysis is done

Which of the following applies to cryoscopic osmometry? See page 124 for choices.

a. The temperature at euilibriun is a function of thenumber of particles in solution.

The first step to be taken when attempting to repair a piece of electronic equipment is:

turn the instrument off

Most of the carbon dioxide present in blood is in the form of:

bicarbonate ion

The degree to which the kidney concentrated the glomerular filtrate can be determined by:

urine to serum osmolality ratio

How many grams of sulfosalicylic acid (MW = 254) are required to prepare 1 L of a 3% (w/v) solution?

30

A physician suspects his patient has pancreatitis. Which test(s) would be most indicative of this disease?

amylase

The statistical term for the average value is the :

mean

An index of precision is statistically known as the:

coefficient of variation

The most frequent value in a collection of data is statistically known as the:

mode

The middle value of a data set is statistically known as the:

median

In a specimen collected for plasma glucose analysis, sodium fluoride:

inhibits glycolysis

In the international system of units serum urea is expressed in millimoles per liter. A serum urea nitrogen concentration of 28 mg/dL would be equivalent to what concentration of urea? (Urea: NH2CONH2; atomic wt N = 14, C = 12, O = 16, H = 1)

10.0 mEq/L

The osmolal gap is defined as measured Osm/kg minus the calculated Osm/kg. The average osmolal gap is near:

0

To be analysed by gas liquid chromatography, a compound must:

be volatile or made volatile

The solute tha tcontributes the most to the total serum osmolality is:

sodium

In automated methods utilizing a bichromatic analyzer. dual wavelengths are employes to:

minimize the effect of interference

What electrode ID is based on the principle of amperometric measurement?

PO2 electrode

One international unit of enzyme activity is the amount of enzyme that, under specified reaction conditions of substrate concentratin, Ph, & temperature, causes utilization of substrate at the rate of:

1 micromole/min

The Porter-Silber method (phemylhydrazine in alcohol and sulfuric acid) involves which part of the steroid molecule?

dihydroxyacetone side chain

Which family of steroid hormones is characterized by an unsaturated A ring?

estrogens

Which of the statments on page 127 about immunoassays using enzyme-labeled antibodies or antigens is correct?

c. Quantitation of the label can be carried out with a spectrophotometer.

What chemical determinations may be of help in establishing the presence of seminal fluid?

acid phosphatase

What serum protein fractions is most likely to be elevated in patients with nephrotic syndrome?

alpha-2 globulin and beta globulin

What wnzyme substrates for prostatic acid phosphatase determination results in the highest specificity?

thymolphthalein monophosphate

The results listes on page 128 were obtained on arterial blood: These results are most compatible with :

respiratory acidosis

Increased total serum lactic dehydrogenase (LD) activity, confined to fractions 4 and 5, is most likely to be associated with:

acute viral hepatitis

Regan isoenzyme has the same properties as alkaline phosphatase that originates in the:

placenta

Assay of transketolase activity in blood is used to select deficiency of:

thiamine

The substance that is measured to estimate the serum concentration of triglycerides by MOST methods is:

glycerol

The most sensitive enzymatic indicator for liver damage from ethanol intake is:

gamma-glutamyl transferase (GGT)

Refer to the illustration on page 129. This electrophoresis pattern is consistant with:

alpha-1 antitrypsin deficiency; severe emphysema

Patients with Cushing's syndrome exhibit:

serum cortisol concentrations greater then 15 mg/dL

A one molal solution is equivalent to:

a solution containing one mole of solute per kg of solvent

Refer to the illustration on page 130. The serum protein electrophoresis pattern is consistant with:

monoclonal gammopathy

Refer to the illustration on page 131. This pattern is consistant with:

cirrhosis

Given the results listed on page 131. This is most consistant with:

acute hepatitis

Given the results listed on page 132. This is most consistent with:

obstructive jaundice

Given the results listed on page 132; This is most consistant with:

chronic hepatitis

Which of the statements on page 132 about fluorometry are true?

A compound is said to flouresce when it absorbs oight at one wavelength and emits litght at a second wavelength.

A benifit of microassays includes:

reduced reagent requirements

Refer to the illustration on page 133. This illustration represents the change in absorbance at 340 nm over a period of * minutes in as assay for lactate dehydrogenase. True statements about this figure include:

Nonlinearity after 6 minutes is due to a substrate exhaustion

A serum sample in the emergency room from a 42-year old man yielded the laboratory results listed on page 133. What condition might account for these values?

crush injury it the thigh

Incompetitive inhibition of an enzyme reaction the:

inhibitor binds to the enzyme at the same site as the substrate

Kernicterus is an abnormal accumulation of bilirubin in:

brain tissue

Two standard deviations is the acceptable limit of error in the chemistry laboratory. If you run the normal control 100 times, how many of the values would ve out of control due to random error?

5

Serum haptoglobin can be sepatated into:

distinct phenotypes by starch-gel electrophoresis

Which serum protein migrates with the beta-globulins on cellulose acetate at pH 8.6?

C3 component of complement

Fasting serum phosphate concentration is controlled primarily by the:

parathyroid glands

Serum 'anion gap' is increased in patients with:

lactic acidosis

Increased serum lactic dehydrogenase activity due to elevation of fast fraction ( 1 and 2) on electrophoretic separation is caused by:

hemolytic anemia

The nanometer is used as a mearure of:

wavelength of radiant energy

Major actions of angiotensin II include:

increased vasoconstriction

The presence of increased CK-MB activity on a CK electrophoresis pattern is most likely found in a patient suffering from:

myocardial infarction

What is the molarity of a solution that contains 18.7 g of KCl (MW=74.5) in a 500 mL of water?

0.5

In the total bilirubin assay, bilirubin reacts with diazotized sulfanilic acid to form:

azobilirubin

Total glycosylated hemoglobin levels in a hemolysate reflect the:

average blood glucose levels of the past 2-3 months

The identification of Bence Jones protein is best accomplished by:

immunofixation

The anion gap is useful for quality control of laboratory results for:

sodium, potassium, chloride, and total CO2

What percentage of total serum calcium is nondiffusible protein bound?

40-50%

The buffering capacity of blood is maintained by a reversible exchange process between bicarbonate and:

chloride

What electrolyte is the cheif plasma cation whose main fumction is maintaining osmotic pressure?

sodium

A reciprocal relationship exists between:

calcium and phosphorus

A colorimetric method calls for the use of 0.1 mL serum, 5 mL of reagent and 4.9 mL of water. What is the dilution of the serum in the final solution?

0.111111111

At blood pH 7.40 what is the ratio between bicarbonate and carbonic acid?

20:01

The bicarbonate and carbonic acid ratio is calculated from an equation by:

Henderson-Hasselbalch

Acidosis and alkosis are best defined as fluctuations in blood pH and CO2 content due to changes in:

bicarbonate buffer

A common cause of respiratory alkalosis is:

hyperventilation

Metabolic acidosis is described as a(n):

decrease in CO2 content and PCO2 with a decreased pH

Respiratory acidosis is described as a(n):

increase in CO2 content and PCO2 with a decreased pH

Normally the bicarbonate concentration is about 24 mEq/L and the carbonic acid concentration is about 1.2; pK=6.1. Using the equation pH=pK +log[salt]/[acid], calculate the pH.

7.4

The normal range for the pH of arterial blood measured at 37 degree C is:

7.35-7.45

Unless blood gas measurements are made immediately after sampling, in vitro glycolysis of the blood causes a:

fall in pH and a rise is PCO2

Hydrogen ion concentration (pH) in blod is usually determined by means of what electrodes?

glass