CLINICAL CHEMISTRY HARR

100問 • 1年前

問題一覧

Of the methods used to measure amino acids, which is capable of measuring fatty acids simultaneously? A. Tandem-mass spectroscopy B. High-performance liquid chromatography C. Capillary electrophoresis D. Two-dimensional thin-layer chromatography

A. Tandem-mass spectroscopy

Blood ammonia levels are usually measured in order to evaluate: A. Renal failure B. Acid–base status C. Hepatic coma D. Gastrointestinal malabsorption

C. Hepatic coma

Enzymatic measurement of ammonia requires which of the following substrates and coenzymes?

Which statement about ammonia is true? A. Normally, most of the plasma ammonia is derived from peripheral blood deamination of amino acids B. Ammonia-induced coma can result from salicylate poisoning C. Hepatic coma can result from Reye’s syndrome D. High plasma ammonia is usually caused by respiratory alkalosis

C. Hepatic coma can result from Reye’s syndrome

SITUATION: A sample for ammonia assay is taken from an IV line that had been capped and injected with lithium heparin (called a heparin lock). The sample is drawn in a syringe containing lithium heparin, and immediately capped and iced. The plasma is separated and analyzed within 20 minutes of collection, and the result is 50 μg/dL higher than one measured 4 hours before. What is the most likely explanation of these results? A. Significantly greater physiological variation is seen with patients having systemic, hepatic, and gastrointestinal diseases B. The syringe was contaminated with ammonia C. One of the two samples was collected from the wrong patient D. Stasis of blood in the line caused increased ammonia

D. Stasis of blood in the line caused increased ammonia

Uric acid is derived from the: A. Oxidation of proteins B. Catabolism of purines C. Oxidation of pyrimidines D. Reduction of catecholamines

B. Catabolism of purines

Which of the following conditions is associated with hyperuricemia? A. Renal failure B. Chronic liver disease C. Xanthine oxidase deficiency D. Paget’s disease of the bone

A. Renal failure

Orders for uric acid are legitimate stat requests because: A. Levels above 10 mg/dL cause urinary tract calculi B. Uric acid is hepatotoxic C. High levels induce aplastic anemia D. High levels cause joint pain

A. Levels above 10 mg/dL cause urinary tract calculi

Which uric acid method is associated with negative bias caused by reducing agents? A. Uricase coupled to the Trinder reaction B. Ultraviolet uricase reaction coupled to catalase and alcohol dehydrogenase reactions C. Measurement of the rate of absorbance decrease at 290 nm after addition of uricase D. Phosphotungstic acid using a protein-free filtrate

A. Uricase coupled to the Trinder reaction

Kjeldahl’s procedure for total protein is based upon the premise that: A. Proteins are negatively charged B. The pKa of proteins is the same C. The nitrogen content of proteins is constant D. Proteins have similar tyrosine and tryptophan content

C. The nitrogen content of proteins is constant

Upon which principle is the biuret method based? A. The reaction of phenolic groups with CuIISO4 B. Coordinate bonds between Cu+2 and carbonyl and imine groups of peptide bonds. C. The protein error of indicator effect producing color when dyes bind protein D. The reaction of phosphomolybdic acid with protein

B. Coordinate bonds between Cu+2 and carbonyl and imine groups of peptide bonds.

Which statement about the biuret reaction for total protein is true? A. It is sensitive to protein levels below 0.1 mg/dL B. It is suitable for urine, exudates, and transudates C. Polypeptides and compounds with repeating imine groups react D. Hemolysis will not interfere

C. Polypeptides and compounds with repeating imine groups react

Which of the following protein methods has the highest analytical sensitivity? A. Refractometry B. Folin–Lowry C. Turbidimetry D. Direct ultraviolet absorption

B. Folin–Lowry

Which of the following statements regarding proteins is true? A. Total protein and albumin are about 10% higher in ambulatory patients B. Plasma total protein is about 20% higher than serum levels C. Albumin normally accounts for about one-third of the cerebrospinal fluid total protein D. Transudative serous fluid protein is about two-thirds of the serum total protein

A. Total protein and albumin are about 10% higher in ambulatory patients

Hyperalbuminemia is caused by: A. Dehydration syndromes B. Liver disease C. Burns D. Gastroenteropathy

A. Dehydration syndromes

High serum total protein but low albumin is usually seen in: A. Multiple myeloma B. Hepatic cirrhosis C. Glomerulonephritis D. Nephrotic syndrome

A. Multiple myeloma

Which of the following conditions is most commonly associated with an elevated level of total protein? A. Glomerular disease B. Starvation C. Liver failure D. Malignancy

D. Malignancy

Which of the following dyes is the most specific for measurement of albumin? A. Bromcresol green (BCG) B. Bromcresol purple (BCP) C. Tetrabromosulfophthalein D. Tetrabromphenol blue

B. Bromcresol purple (BCP)

Which of the following factors is most likely to cause a falsely low result when using the BCG dye-binding assay for albumin? A. The presence of penicillin B. An incubation time of 120 seconds C. The presence of bilirubin D. Lipemia

A. The presence of penicillin

At pH 8.6, proteins are _________ charged and migrate toward the _________. A. Negatively, anode B. Positively, cathode C. Positively, anode D. Negatively, cathode

A. Negatively, anode

Electrophoretic movement of proteins toward the anode will decrease by increasing the: A. Buffer pH B. Ionic strength of the buffer C. Current D. Voltage

B. Ionic strength of the buffer

At pH 8.6, the cathodal movement of ? globulins is caused by: A. Electroendosmosis B. Wick flow C. A net positive charge D. Cathodal sample application

A. Electroendosmosis

Which of the following conditions will prevent any migration of proteins across an electrophoretic support medium such as agarose? A. Using too high a voltage B. Excessive current during the procedure C. Loss of contact between a buffer chamber and the medium D. Evaporation of solvent from the surface of the medium

C. Loss of contact between a buffer chamber and the medium

Which of the following proteins has the highest pI? A. Albumin B. Transferrin C. Ceruloplasmin D. IgG

D. IgG

Which of the following proteins migrates in the β region at pH 8.6? A. Haptoglobin B. Orosomucoprotein C. Antichymotrypsin D. Transferrin

D. Transferrin

Which of the following is one advantage of high-resolution (HR) agarose electrophoresis over lower-current electrophoresis? A. High-resolution procedures detect monoclonal and oligoclonal bands at a lower concentration B. A smaller sample volume is used C. Results are obtained more rapidly D. Densitometric scanning of HR gels is more accurate

A. High-resolution procedures detect monoclonal and oligoclonal bands at a lower concentration

Which of the following conditions is associated with “ß-? bridging”? A. Multiple myeloma B. Malignancy C. Hepatic cirrhosis D. Rheumatoid arthritis

C. Hepatic cirrhosis

Which support medium can be used to determine the molecular weight of a protein? A. Cellulose acetate B. Polyacrylamide gel C. Agar gel D. Agarose gel

B. Polyacrylamide gel

Which of the following stains is used for lipoprotein electrophoresis? A. Oil Red O B. Coomassie Brilliant Blue C. Amido Black D. Ponceau S

A. Oil Red O

Which of the following serum protein electrophoresis results suggests an acute inflammatory process?

Which of the following conditions is usually associated with an acute inflammatory pattern? A. Myocardial infarction (MI) B. Malignancy C. Rheumatoid arthritis D. Hepatitis

A. Myocardial infarction (MI)

The electrophoretic pattern shown in the following densitometric tracing most likely indicates: A. α1-Antitrypsin deficiency B. Infection C. Nephrosis D. Systemic sclerosis

A. α1-Antitrypsin deficiency

What is the clinical utility of testing for serum prealbumin? A. Low levels are associated with increased free cortisol B. High levels are an indicator of acute inflammation C. Serial low levels indicate compromised nutritional status D. Levels correlate with glomerular injury in patients with diabetes mellitus

C. Serial low levels indicate compromised nutritional status

Which serum protein should be measured in a patient suspected of having Wilson’s disease? A. Hemopexin B. Alpha-1 antitrypsin C. Haptoglobin D. Ceruloplasmin

D. Ceruloplasmin

A patient with hemolytic-uremic syndrome associated with septicemia has a haptoglobin level that is normal, although the plasma free hemoglobin is elevated and hemoglobinuria is present. Which test would be more appropriate than haptoglobin to measure this patient’s hemolytic episode? A. Hemopexin B. Alpha-1 antitrypsin C. C-reactive protein D. Transferrin

A. Hemopexin

Quantitative determination of Hgb A2 and Hgb F are best performed by: A. High-performance liquid chromatography B. Alkali denaturation C. Electrophoresis D. Direct bichromatic spectrophotometry

A. High-performance liquid chromatography

Select the correct order of Hgb migration on agarose or cellulose acetate at pH 8.6. A. – C→F→S→A + B. – S→C→A→F + C. – C→S→F→A + D. – S→F→A→C +

C. – C→S→F→A +

Which of the following abnormal types of Hgb migrates to the same position as Hgb S on agarose or cellulose acetate at pH 8.6? A. Hgb C B. Hgb DPunjab C. Hgb OArab D. Hgb E

B. Hgb DPunjab

Which Hgb is a β-δ chain hybrid and migrates to the same position as Hgb S at pH 8.6? A. Hgb CHarlem B. HgbLepore C. Hgb GPhiladelphia D. Hgb DPunjab

B. HgbLepore

Select the correct order of Hgb migration on citrate agar at pH 6.2. A. – F→S→C→A + B. – F→A→S→C + C. – A→S→F→C + D. – A→C→S→F +

B. – F→A→S→C +

Which Hgb separates from Hgb S on citrate (acid) agar, but not agarose or cellulose acetate? A. Hgb DPunjab B. Hgb E C. Hgb CHarlem (Georgetown) D. Hgb OArab

A. Hgb DPunjab

Which statement best describes immunofixation electrophoresis (IEF)? A. Proteins are separated by electrophoresis followed by overlay of monospecific anti-immunoglobulins B. Proteins react with monospecific antisera followed by electrophoresis C. Antisera are electrophoresed, then diffused against patient’s serum D. Serum is electrophoresed; the separated immunoglobulins diffuse against specific antisera placed into troughs

A. Proteins are separated by electrophoresis followed by overlay of monospecific anti-immunoglobulins

In double immunodiffusion reactions, the precipitin band is: A. Invisible before the equivalence point is reached B. Concave to the protein of greatest molecular weight C. Closest to the well containing the highest level of antigen D. Located in an area of antibody excess

B. Concave to the protein of greatest molecular weight

Which of the following statements regarding the identification of monoclonal proteins by IFE is true? A. The monoclonal band must be present in the γ region B. When testing for a monoclonal gammopathy, both serum and urine must be examined C. A diagnosis of monoclonal gammopathy is based upon quantitation of IgG, IgA, and IgM D. A monoclonal band always indicates a malignant disorder

B. When testing for a monoclonal gammopathy, both serum and urine must be examined

Which of the following statements regarding paraproteins is true? A. Oligoclonal banding is seen in the CSF of greater than 90% of multiple sclerosis cases B. The Bence–Jones protein heat test is confirmatory for monoclonal light chains C. Light chains found in urine are always derived from monoclonal protein D. The IgA band is usually cathodal to the IgG precipitin band

A. Oligoclonal banding is seen in the CSF of greater than 90% of multiple sclerosis cases

Which statement regarding IFE is true? A. Serum containing a monoclonal protein should have a κ:λ ratio of 0.5 B. A monoclonal band seen with monospecific antiserum should not be visible in the lane where polyvalent antiserum or sulfosalicylic acid was added C. CSF should be concentrated 50- to100-fold before performing IFE D. When oligoclonal bands are seen in the CSF, they must also be present in serum to indicate multiple sclerosis

C. CSF should be concentrated 50- to100-fold before performing IFE

Which test is the most sensitive in detecting early monoclonal gammopathies? A. High-resolution serum protein electrophoresis B. Urinary electrophoresis for monoclonal light chains C. Capillary electrophoresis of serum and urine D. Serum-free light chain immunoassay

D. Serum-free light chain immunoassay

Which test is the most useful way to evaluate the response to treatment for multiple myeloma? A. Measure of total immunoglobulin B. Measurement of 24-hour urinary light chain concentration (Bence–Jones protein) C. Capillary electrophoresis of M-protein recurrence D. Measurement of serum-free light chains

D. Measurement of serum-free light chains

Which of the following is more commonly associated with a nonmalignant form of monoclonal gammopathy (MGUS)? A. Bone marrow plasma cells comprise 20% of nucleated cells B. Monoclonal protein (M-protein) concentration is 3.5 g/dL C. M-protein is IgG D. Age greater than 60 at the time of monoclonal protein discovery

D. Age greater than 60 at the time of monoclonal protein discovery

Capillary electrophoresis differs from agarose gel electrophoresis in which respect? A. A stationary support is not used B. An acidic buffer is used C. A low voltage is used D. Electroendosmosis does not occur

A. A stationary support is not used

Select the order of mobility of lipoproteins electrophoresed on cellulose acetate or agarose at pH 8.6. A. – Chylomicrons→pre-β →β→α+ B. – β→pre-β→α→chylomicrons + C. – Chylomicrons →β→pre-β→α + D. – α→β→pre-β→chylomicrons +

C. – Chylomicrons →β→pre-β→α +

Following ultracentrifugation of plasma, which fraction correlates with pre-β lipoprotein? A. Very low-density lipoprotein (VLDL) B. Low-density lipoprotein (LDL) C. High-density lipoprotein (HDL) D. Chylomicrons

A. Very low-density lipoprotein (VLDL)

Select the lipoprotein fraction that carries most of the endogenous triglycerides. A. VLDL B. LDL C. HDL D. Chylomicrons

A. VLDL

The protein composition of HDL is what percentage by weight? A. Less than 2% B. 25% C. 50% D. 90%

C. 50%

Which apoprotein is inversely related to risk of coronary heart disease? A. Apoprotein A-I B. Apoprotein B100 C. Apoprotein C-II D. Apoprotein E4

A. Apoprotein A-I

In familial ß dyslipoproteinemia (formerly type III hyperlipoproteinemia), which lipoprotein accumulates? A. Chylomicrons B. VLDL C. IDL D. VLDL

C. IDL

Which of the following mechanisms accounts for the elevated plasma level of ß lipoproteins seen in familial hypercholesterolemia (formerly type II hyperlipoproteinemia)? A. Hyperinsulinemia B. ApoB-100 receptor defect C. ApoC-II activated lipase deficiency D. ApoE3 deficiency

B. ApoB-100 receptor defect

Which enzyme deficiency is most commonly associated with familial hypertriglyceridemia associated with fasting plasma cholomicrons (formerly type I hyperlipoproteinemia)? A. β Glucocerebrosidase deficiency B. Post–heparin-activated lipoprotein lipase deficiency C. Apo-B deficiency D. Apo-C-III deficiency

C. Apo-B deficiency

Which of the following conditions is most consistently associated with secondary hypercholesterolemia? A. Hypothyroidism B. Pancreatitis C. Oral contraceptive therapy D. Diabetes mellitus

A. Hypothyroidism

Which of the following is associated with Tangier disease? A. Apoprotein C-II deficiency B. Homozygous apo-B100 deficiency C. Apoprotein C-II activated lipase D. Apoprotein A-I deficiency

D. Apoprotein A-I deficiency

Which of the following statements is correct? A. Both HDL and LDL are homogenous B. There are several subfractions of LDL but not HDL C. There are several subfractions of HDL but not LDL D. There are several subfractions of both HDL and LDL

D. There are several subfractions of both HDL and LDL

What is the lipid testing protocol for adults recommended by the National Cholesterol Education Program (NCEP) to evaluate risk for atherosclerosis beginning at age 20? A. Total cholesterol, fasting or nonfasting every year B. Total cholesterol, fasting, every 2 years C. Lipid profile, fasting, every 5 years D. LDL cholesterol, fasting, every 2 years

C. Lipid profile, fasting, every 5 years

What is the most appropriate fasting procedure when a lipid study of triglyceride, total cholesterol, HDL cholesterol, and LDL cholesterol tests are ordered? A. 8 hours; nothing but water allowed B. 10 hours; water, smoking, coffee, tea (no sugar or cream) allowed C. 12 hours; nothing but water allowed D. 16 hours; water, smoking, coffee, tea (no sugar or cream) allowed

C. 12 hours; nothing but water allowed

Treatment recommendations for patients with coronary heart disease are based upon measurement of which analyte? A. HDL cholesterol B. Apo-B100 C. LDL cholesterol D. Total cholesterol

C. LDL cholesterol

What is the HDL cholesterol cutpoint recommend by NCEP? A. <30 mg/dL B. <40 mg/dL C. <30 mg/dL for males and < 40 mg/dL for females D. <45 mg/dL for males and < 50 mg/dL for females

B. <40 mg/dL

An EDTA blood sample is collected from a nonfasting person for a CBC. The physician collected the sample from the femoral vein because venipuncture from the arm was unsuccessful. He called the lab 15 minutes after the sample arrived and requested a lipid study including triglyceride, total cholesterol, HDL cholesterol, and LDL cholesterol. Which test results should be used to evaluate the patient’s risk for coronary artery disease? A. Total cholesterol and LDL cholesterol B. LDL cholesterol and triglyceride C. Total cholesterol and HDL cholesterol D. Total cholesterol and triglyceride

C. Total cholesterol and HDL cholesterol

Which of the following diseases is caused by a deficiency of sphingomyelinase? A. Gaucher disease B. Fabry disease C. Niemann–Pick disease D. Tay–Sachs disease

C. Niemann–Pick disease

Which method is considered the candidate reference method for triglyceride measurement? A. Glycerol kinase-ultraviolet B. CDC modification of van Handel and Zilversmit C. Hantzsch condensation D. Glycerol kinase coupled to peroxidase

B. CDC modification of van Handel and Zilversmit

Which of the following enzymes is common to all enzymatic methods for triglyceride measurement? A. Glycerol phosphate oxidase B. Glycerol phosphate dehydrogenase C. Glycerol kinase D. Pyruvate kinase

C. Glycerol kinase

Select the reagent needed in the coupling enzyme reaction used to generate a colored product in the cholesterol oxidase method for cholesterol. A. Cholestahexaene B. H2O2 C. 4-Aminoantipyrine D. Cholest-4-ene-3-one

C. 4-Aminoantipyrine

What is the purpose of the saponification step used in the Abell–Kendall method for cholesterol measurement? A. Remove phospholipids B. Reduce sterol molecules structurally similar to cholesterol C. Convert cholesterol esters to free cholesterol D. Remove proteins that can interfere with color formation

C. Convert cholesterol esters to free cholesterol

Which of the following methods for HDL cholesterol is the reference method? A. Manganese–heparin B. Magnesium–phosphotungstate C. Magnesium–dextran D. Ultracentrifugation

D. Ultracentrifugation

Cholesterol esterase is used in enzymatic assays to: A. Oxidize cholesterol to form peroxide B. Hydrolyze fatty acids bound to the third carbon atom of cholesterol C. Separate cholesterol from apoproteins A-I and A-II by hydrolysis D. Reduce NAD+ to NADH

B. Hydrolyze fatty acids bound to the third carbon atom of cholesterol

Which of the following reagents is used in the direct HDL cholesterol method? A. Sulfated cyclodextrin B. Magnesium sulfate and dextran sulfate C. Anti-apoA-I D. Manganese heparin

A. Sulfated cyclodextrin

What do “direct” or homogenous methods for LDL cholesterol assay have in common? A. They are inaccurate when plasma triglyceride is above 250 mg/dL B. All use a detergent to facilitate selective reactivity with reagent enzymes C. All use monoclonal antibodies to apo A1 and C D. All are free of interference from abnormal lipoproteins

B. All use a detergent to facilitate selective reactivity with reagent enzymes

Lipoprotein (a), or Lp(a), is significant when elevated in serum because it: A. Is an independent risk factor for atherosclerosis B. Blocks the clearance of VLDLs C. Displaces apo-AI from HDLs D. Is linked closely to a gene for obesity

A. Is an independent risk factor for atherosclerosis

Which type of dietary fatty acid is not associated with an increase in serum LDL cholesterol production? A. Monounsaturated trans fatty acids B. Saturated fatty acids C. Monounsaturated cis fatty acids D. Monounsaturated trans O-9 fatty acids

C. Monounsaturated cis fatty acids

SITUATION: A lipemic specimen collected from an adult after a 12-hour fast was assayed for total cholesterol, triglycerides, and HDL cholesterol using a direct HDL method. Following are the results: Total cholesterol = 220 mg/dL HDL cholesterol = 40 mg/dL Triglyceride = 420 mg/dL The physician requests an LDL cholesterol assay after receiving the results. How should the LDL cholesterol be determined? A. Dilute the specimen 1:10 and repeat all tests; calculate LDL cholesterol using the Friedewald equation B. Perform a direct LDL cholesterol assay C. Ultracentrifuge the sample and repeat the HDL cholesterol on the infranate. Use the new result to calculate the LDL cholesterol D. Repeat the HDL cholesterol using the manganese heparin precipitation method. Use the new result to calculate the LDL cholesterol

B. Perform a direct LDL cholesterol assay

A person has a fasting triglyceride level of 240 mg/dL. The physician wishes to know the patient’s non-HDL cholesterol level. What cholesterol fractions should be measured? A. Total cholesterol and HDL cholesterol B. Total cholesterol and LDL cholesterol C. HDL cholesterol and LDL cholesterol D. Total cholesterol and chylomicrons

A. Total cholesterol and HDL cholesterol

An international unit (IU) of enzyme activity is the quantity of enzyme that: A. Converts 1 μmol of substrate to product per liter B. Forms 1 mg of product per deciliter C. Converts 1 μmol of substrate to product per minute D. Forms 1 μmol of product per liter

C. Converts 1 μmol of substrate to product per minute

Which of the following statements describes a nonkinetic enzyme assay? A. Initial absorbance is measured followed by a second reading after 5 minutes B. Absorbance is measured at 10-second intervals for 100 seconds C. Absorbance is monitored continuously for 1 minute using a chart recorder D. Reflectance is measured from a xenon source lamp pulsing at 60 Hz

A. Initial absorbance is measured followed by a second reading after 5 minutes

Which of the following statements regarding enzymatic reactions is true? A. The enzyme shifts the equilibrium of the reaction to the right B. The enzyme alters the equilibrium constant of the reaction C. The enzyme increases the rate of the reaction D. The enzyme alters the energy difference between reactants and products

C. The enzyme increases the rate of the reaction

Which statement about enzymes is true? A. An enzyme alters the Gibb’s free energy of the reaction B. Enzymes cause a reaction with a positive free energy to occur spontaneously C. An enzyme’s natural substrate has the highest Km D. A competitive inhibitor will alter the apparent Km of the reaction

D. A competitive inhibitor will alter the apparent Km of the reaction

Which substrate concentration is needed to achieve zero-order conditions? A. Greater than 99 × Km B. [S] = Km C. Less than 10 × Km D. [S] = 0

A. Greater than 99 × Km

Which of the following statements is true? A. Apoenzyme + prosthetic group = holoenzyme B. A coenzyme is an inorganic molecule required for activity C. Cofactors are as tightly bound to the enzyme as prosthetic groups D. All enzymes have optimal activity at pH 7.00

A. Apoenzyme + prosthetic group = holoenzyme

Which of the following statements about enzymatic reactions is true? A. NADH has absorbance maximas at 340 and 366 nm B. Enzyme concentration must be in excess to achieve zero-order kinetics C. Rate is proportional to substrate concentration in a zero-order reaction D. Accumulation of the product increases the reaction rate

enzymatic reactions is true? A. NADH has absorbance maximas at 340 and 366 nm

The increase in the level of serum enzymes used to detect cholestatic liver disease is caused mainly by: A. Enzyme release from dead cells B. Leakage from cells with altered membrane permeability C. Decreased perfusion of the tissue D. Increased production and secretion by cells

D. Increased production and secretion by cells

Which of the following enzymes is considered most tissue specific? A. Creatine kinase (CK) B. Amylase C. Alkaline phosphatase (ALP) D. Alcohol dehydrogenase (ADH)

D. Alcohol dehydrogenase (ADH)

Which of the following enzymes is activated by calcium ions? A. CK B. Amylase C. ALP D. LD

B. Amylase

Which of the following enzymes is a transferase? A. ALP B. CK C. Amylase D. LD

B. CK

Which statement about methods for measuring LD is true? A. The formation of pyruvate from lactate (forward reaction) generates NAD+ B. The pyruvate-to-lactate reaction proceeds at about twice the rate as the forward reaction C. The lactate-to-pyruvate reaction is optimized at pH 7.4 D. The negative-rate reaction is preferred

B. The pyruvate-to-lactate reaction proceeds at about twice the rate as the forward reaction

Which condition produces the highest elevation of serum lactate dehydrogenase? A. Pernicious anemia B. Myocardial infarction C. Acute hepatitis D. Muscular dystrophy

A. Pernicious anemia

In which condition is the LD most likely to be within normal limits? A. Hepatic carcinoma B. Pulmonary infarction C. Acute appendicitis D. Crush injury

C. Acute appendicitis

The LD pleural fluid:serum ratio for a transudative fluid is usually: A. 3:1 or higher B. 2:1 C. 1:1 D. 1:2 or less

D. 1:2 or less

In which type of liver disease would you expect the greatest elevation of LD? A. Toxic hepatitis B. Alcoholic hepatitis C. Cirrhosis D. Acute viral hepatitis

A. Toxic hepatitis

Which of the following conditions will interfere with the measurement of LD? A. Slight hemolysis during sample collection B. Storage at 4°C for 3 days C. Storage at room temperature for 16 hours D. Use of plasma collected in heparin

A. Slight hemolysis during sample collection

In the Oliver–Rosalki method, the reverse reaction is used to measure CK activity. The enzyme(s) used in the coupling reactions is (are): A. Hexokinase and G-6-PD B. Pyruvate kinase and LD C. Luciferase D. Adenylate kinase

A. Hexokinase and G-6-PD

In the Oliver–Rosalki method for CK, adenosine monophosphate (AMP) is added to the substrate in order to: A. Inhibit adenylate kinase B. Block the oxidation of glutathione C. Increase the amount of ADP that is available D. Block the action of diadenosine pentaphosphate

A. Inhibit adenylate kinase

Which substance is used in the CK assay to activate the enzyme? A. Flavin adenine dinucleotide (FAD) B. Imidazole C. N-acetylcysteine D. Pyridoxyl-5´-phosphate

C. N-acetylcysteine

100

SITUATION: A specimen for CK performed on an automated analyzer using an optimized Oliver–Rosalki method gives an error flag indicating substrate depletion. The sample is diluted 1:2 and 1:4 by the serial dilution technique and reassayed. After correcting for the dilution, the results are as follows: 1:2 Dilution = 3,000 IU/L 1:4 Dilution = 3,600 IU/L Dilutions are made a second time and assayed again but give identical results. What is the most likely explanation? A. The serum became contaminated prior to making the 1:4 dilution B. The wrong pipet was used to make one of the dilutions C. An endogenous competitive inhibitor is present in the serum D. An error has been made in calculating the enzyme activity of one of the two dilutions

C. An endogenous competitive inhibitor is present in the serum

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Yves Laure Pimentel · 64問 · 2年前

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