Clinical Chemistry Ch 12-14
Which of the following best describes the correct collection and handling conditions for a blood ammonia measurement? a. Fasting patient, draw clot tube, separate serum immediately, test immediately b. Draw sodium heparin tube, place in ice bath immediately, separate cells and plasma in refrigerated centrifuge, immediately remove plasma and freeze if analytical testing is delayed c. Draw clot tube, separate serum from clot in refrigerated centrifuge, protect from light, freeze if not tested immediately d. Fasting patient, draw lithium heparin tube, place tube on an ice pack, centrifuge at 20° C, test immediately
b. Draw sodium heparin tube, place in ice bath immediately, separate cells and plasma in refrigerated centrifuge, immediately remove plasma and freeze if analytical testing is delayed
When a purified enzyme is used as a reagent, such as urease in the measurement of urea, the enzyme must be ________________ concentration so that the reaction follows _________________ kinetics. a. Limited; first b. Excess; first c. Limited; zero d. Excess; zero
b. Excess; first
Which of the following enzymes detects very early changes in liver cell damage? a. ALP b. GGT c. ALT d. Cholinesterase e. SGPT
b. GGT
In the Szasz method for gamma glutamyl transferase (GGT), the typical receptor molecule is: a. Gamma glutamyl p-nitroanilide b. Glycyl glycine c. Glutathione d. Aminonitrobenzoate
b. Glycyl glycine
The reference method for glucose determination is: a. Glucose dehydrogenase b. Hexokinase c. Glucose oxidase d. Copper-reduction
b. Hexokinase
Urea: a. Is synthesized in the liver from the breakdown of nucleic acids b. Is synthesized from CO2 and ammonia c. Can produce Reye's syndrome when present in high amounts in blood d. Is increased in serum during acute episodes of gout.
b. Is synthesized from CO2 and ammonia
A reaction in which NAD+ or NADP+ is formed from reagent NADH or NADPH is ________ and may be measured by a(an) ________ in absorbance at 340 nm. a. Oxidation; increase b. Oxidation; decrease c. Reduction; increase d. Reduction; decrease
b. Oxidation; decrease
The greatest tissue source of CK is: a. Heart muscle b. Skeletal muscle c. Brain d. Thyroid
b. Skeletal muscle
The preferred collection tube for preservation of glucose is: a. Calcium oxalate b. Sodium fluoride c. Lithium heparin d. Sodium citrate
b. Sodium fluoride
A toxic condition involving a very high serum level of urea and creatinine accompanied by failure of the three main functions of the renal system is referred to as: a. Acute glomerulonephritis b. Uremia c. Azotemia. d. Acute renal failure
b. Uremia
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are both elevated in which of the following diseases? a. Muscular dystrophy b. Viral hepatitis c. Myocardial infarction d. Obstructive liver disease
b. Viral hepatitis
A serum specimen for glucose measurement was allowed to stand unseparated on the clot for 6 hours at room temperature before testing. If the original glucose concentration was 200 mg/dL, what approximate results would be expected after 3 hours? a. 240 mg/dL b. No change in results c. 160 mg/dL d. 150 mg/dL
c. 160 mg/dL
Insulin may be described by all of the following EXCEPT: a. Synthesized from proinsulin b. Synthesized by beta cells in the pancreas c. Active in its C-peptide form d. Two-chain polypeptide e. Combines with insulin receptors
c. Active in its C-peptide form
A reaction rate assay measures enzyme ____________________; an endpoint assay measures enzyme ______________________. a. Activity; concentration b. Concentration; activity c. Activity; activity d. Concentration; concentration
c. Activity; activity
One extracellular enzyme whose serum activity is measured clinically is: a. Lactate dehydrogenase b. Creatine kinase c. Amylase d. Alkaline phosphatase
c. Amylase
Which of the following enzymes requires chloride (Cl-) as an activator? a. Gamma glutamyl transferase (GGT) b. Lipase c. Amylase d. Cholinesterase
c. Amylase
The glucose value of a NORMAL 2-hour post-prandial serum specimen, as compared to the reference range for a fasting serum glucose, should be: a. Significantly greater than the normal fasting glucose level b. Significantly lower than the normal fasting glucose level c. Approximately the same as the normal fasting glucose level d. Unrelated to each other
c. Approximately the same as the normal fasting glucose level
The major non-glucose-reducing substance present in serum is: a. Urea b. Protein c. Ascorbic acid d. Glutathione e. Cholesterol
c. Ascorbic acid
The ____________ form of glucose is responsible for its reducing properties. a. Ketone b. Aldehyde c. Enol d. Pyranose e. Hemiacetal
c. Enol
The most sensitive enzymatic indicator for liver damage from ethanol intake is: a. Alanine aminotransferase (ALT) b. Aspartate aminotransferase (AST) c. Gamma-glutamyl transferase (GGT) d. Alkaline phosphatase
c. Gamma-glutamyl transferase (GGT)
Which of the following inhibits glycolysis and glucose uptake by muscle cells and causes a rise in blood glucose concentration? a. Parathyroid hormone b. Calcitonin c. Growth hormone d. Gastrin
c. Growth hormone
Which of the following enzyme tests is most affected by "hemolysis? a. Creatine kinase b. Gamma glutamyl transferase c. Lactate dehydrogenase d. Alkaline phosphatase
c. Lactate dehydrogenase
The major causes of decreased plasma urea concentration include: a. Congestive heart failure b. Glomerular nephritis c. Low protein intake and severe liver disease d. Tubular necrosis e. Obstruction of urine flow by renal calculi
c. Low protein intake and severe liver disease
One International Unit is defined as one __________ of substrate converted to product per ___________. a. Nanogram; hour b. Microgram; minute c. Micromole; minute d. Mole; minute e. Micromole; hour
c. Micromole; minute
The major cellular origin of acid phosphatase activity in serum is: a. Bone b. Pancreas c. Prostate d. Liver
c. Prostate
In the Beckman Analyzer for glucose, H2O2 is consumed in side reactions by: a. Methanol and peroxidase b. Gluconic acid c. Glucose oxidase and oxygen d. Catalase and ethyl alcohol
d. Catalase and ethyl alcohol
The formation of glucose from compounds like fatty acids, glycerol, and amino acids is called: a. Glycolysis b. Glycogenesis c. Glycogenolysis d. Gluconeogenesis
d. Gluconeogenesis
β-glucose + O2 ----?-----> D-glucono-δ-lactone + H2O2 a. Glucose dehydrogenase b. Hexokinase c. Peroxidase d. Glucose oxidase
d. Glucose oxidase
A diabetic patient is prescribed a daily regimen of insulin. Which of the following laboratory procedures would be of most value in determining the degree of glucose control over a 2-month period? a. Fasting blood glucose b. 2-h PP glucose c. OGTT d. Glycated hemoglobin e. Fructosamine
d. Glycated hemoglobin
Which of the following methods for glucose results in the formation of NADPH for measurement? a. Glucose oxidase b. Copper reduction c. Ortho-toluidine d. Hexokinase e. Glucose dehydrogenase
d. Hexokinase
The enzyme that is inhibited by hemoglobin is: a. Creatine kinase b. Cholinesterase c. Alkaline phosphatase d. Lipase
d. Lipase
Which of the following is NOT considered a coenzyme? a. NADH b. Pyridoxal phosphate c. NADPH d. Magnesium
d. Magnesium
Laboratory tests are performed on a post-menopausal, 57-year-old woman as part of an annual physical examination. The patient's 2-hour post-prandial glucose is 220 mg/dL and serum insulin is 15 μU/ml (normal = 6-26). Based on this information, the patient would be classified as: a. Normal glucose tolerance (NGT) b. Gestational diabetes mellitus (GDM) c. Insulin-dependent diabetes mellitus (IDDM) d. Non-insulin-dependent diabetes mellitus (NIDDM)
d. Non-insulin-dependent diabetes mellitus (NIDDM)
Prostatic acid phosphatase measurement has been replaced by: a. RBC ACP b. CPK c. ALP d. PSA
d. PSA
An elevated aldolase level and normal myoglobin is most indicative of: a. Portal cirrhosis b. Acute muscle trauma c. Obstructive jaundice d. Progressive muscular dystrophy
d. Progressive muscular dystrophy
Monitoring of _______ in patients on chemotherapy due to leukemia, lymphoma or multiple myeloma is necessary to avoid nephrotoxicity. a. Serum creatinine b. Urine creatinine c. BUN d. Serum uric acid e. Urea in urine
d. Serum uric acid
In the commonly used ("Caraway") colorimetric method for uric acid in serum, interference from other reducing substances such as ascorbic acid is minimized by the addition of: a. Phosphotungstic acid b. Sodium cyanide c. Urease d. Sodium carbonate
d. Sodium carbonate
Type 1 diabetes mellitus may be described by all of the following EXCEPT: a. Insulin dependent b. Associated with autoimmune destruction of B cells c. Insulinopenia d. Ketoacidosis prone e. Adult-onset type
e. Adult-onset type
Which of the following enzymes has multiple molecular forms (isoenzymes) whose clinical significance is used in diagnosis? a. Lactate dehydrogenase b. Creatine kinase c. Alkaline phosphatase d. Lactate dehydrogenase and creatine kinase only e. Lactate dehydrogenase, creatine kinase, and alkaline phosphatase
e. Lactate dehydrogenase, creatine kinase, and alkaline phosphatase
Which of the following statements may be associated with the activity of insulin? a. Increases blood glucose levels b. Decreases glucose uptake by muscle and fat cells c. Decreases cell membrane permeability to glucose d. Stimulates release of hepatic glucose into the blood e. Stimulates glycogenesis in the liver
e. Stimulates glycogenesis in the liver
In a "kinetic" or "rate" reaction, one spectrophotometric measurement is taken at the end of an incubation period. (True or False)
False
Serum urea levels are less affected by diet and metabolism than are serum creatinine levels. (True or False)
False
An enzymatic method for creatinine on the Vitros (Kodak Ektachem) analyzer uses the reagent enzyme creatinine amidohydrolase. (True or False)
True
Indirect urea methods begin with the hydrolysis of urea to ammonia. (True or False)
True
Serum uric acid levels may be elevated in patients undergoing cancer chemotherapy. (True or False)
True
Which of the following methods of measuring enzyme activity utilizes an increase in absorbance at 340 nm as an indicator reaction? a. "Forward" LD reaction b. "Reverse" LD reaction c. AST(GOT) reaction d. ALT(GPT) reaction
a. "Forward" LD reaction
Azotemia refers to: a. An increase in urea in blood b. An increase in creatinine in urine c. A decrease in BUN in blood d. A decrease in BUN in CSF e. An increase in creatinine in blood
a. An increase in urea in blood
When myocardial infarction occurs, the first enzyme to reach peak elevation is: a. CK b. LD c. AST d. ALT
a. CK
During 3 glucose tests an hour apart on a patient, capillary blood is substituted for venous blood for one of the timed samples. What results would you expect for the sample, as compared to results expected for venous blood drawn at the same time? a. Capillary blood will yield higher results than venous blood b. Venous blood will yield higher results than capillary blood c. Results from capillary and venous blood will be substantially the same
a. Capillary blood will yield higher results than venous blood
Given the following lab results, what is the most likely cause of this patient's BUN? BUN 45 mg/dL Creatinine 1.8 mg/dL Uric Acid 7 mg/dL pH 7.22 pCO2 74.4 mm Hg pO2 32.8 mm Hg O2 sat 51.3% a. Congestive heart failure b. Chronic renal disease c. Dialysis d. Acute tubular necrosis
a. Congestive heart failure BUN 45 mg/dL *HIGH* Creatinine 1.8 mg/dL *high* Uric Acid 7 mg/dL (high end of normal range) pH 7.22 *LOW* (acidotic) pCO2 74.4 mm Hg *HIGH* pO2 32.8 mm Hg *LOW* O2 sat 51.3% *LOW*
In the spectrophotometric determination of AST, malic dehydrogenase catalyzes the conversion of: a. Oxalacetate to malate b. Malate to isocitrate c. Pyruvate to malate d. Alpha-ketoglutarate to malate
a. Oxalacetate to malate
Urea can be measured in all of the following ways EXCEPT: a. The Caraway method b. Ammonium ions generated by the urease reaction leading to a detectable pH change c. Electrode to measure the rate of increase in conductivity as ammonium ions d. Isotope-dilution mass spectrometry
a. The Caraway method
The abbreviated Modification of Diet in Renal Disease (MDRD) equation considers all of the following variables EXCEPT: a. Urine creatinine concentration b. Serum creatinine concentration c. Age d. Gender e. Ethnicity
a. Urine creatinine concentration
Of the following, the only clinically analyzed enzyme in the urine is: a. Cholinesterase b. Amylase c. Acid phosphatase d. Alanine transferase
b. Amylase
Of the following drug therapies, which is MOST likely to interfere with the Jaffe chemistry for measuring creatinine? a. Aspirin b. Cephalosporin c. Acetaminophen d. High water intake e. Low water intake
b. Cephalosporin
The following glucose tolerance test results are indicative of what state? Glucose values as assayed by glucose oxidase method are fasting, 130 mg/dL; 60 minutes, 225 mg/dL; and 120 minutes, 205 mg/dL. a. Normal b. Diabetes c. Addison's disease d. Hyperinsulinism
b. Diabetes
Glycation of glomerular basement membranes and capillaries is the main nephropathic effect from: a. Renal arteriosclerosis b. Diabetes mellitus c. Systemic lupus erythematosus d. Glomerulonephritis
b. Diabetes mellitus
