Exam4 Flashcards

1
Q

What is the substrate for the enzyme aspartate amino transferase (AST)?

A

aspartate and alpha ketoglutamic acid

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2
Q

Creatinine is formed from the breakdown of?

A

creatine

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3
Q

What is the principle of the Berthelot reaction?

A

hydrolysis of urea to ammonium carbonate by enzyme urease ammonia; ammonium reacts with phenol and sodium hypochlorite to form a blue colored indophenol

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4
Q

Increased ALT values are associated with diseases of the?

A

liver

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5
Q

What is the normal value for serum AST at 37C?

A

5-35 IU/L

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6
Q

Which anticoagulant should not be used for urease testing?

A

sodium fluoride

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7
Q

What is the normal percentage of the CK-MB isoenzyme?

A

less than 6%

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8
Q

What reagent is used in the measurement of uric acid?

A

phosphotungstic acid

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9
Q

What additional information must be known for creatinine clearance test if the patient is an infant, young child, or adolescent?

A

body surface area

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10
Q

What is the most common endogenous substance used to assess the glomerular filtration rate?

A

creatinine

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11
Q

Serum creatine kinase is most often elevated in disease of?

A

muscle tissue

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12
Q

What is uremia?

A

urea in the blood

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13
Q

Define international unit

A

quantity of enzyme that will catalyze the reaction of one µmol of substrate per minute

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14
Q

What is the peak absorbance of reduced NAD (NADH)?

A

340 nm

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15
Q

Which non-protein nitrogen component comprises the largest fraction of NPN in the blood?

A

urea/BUN

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16
Q

Gout is caused by the deposition of what in the joints and other tissues?

A

uric acid

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17
Q

What is the clinical significance of a mildly elevated ALP in a teenager?

A

they are growing so fast that it is not significant

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18
Q

What is the normal ratio of BUN to creatinine?

A

10:1 to 15:1

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19
Q

PSP is removed from the blood by the?

A

kidney

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20
Q

L-tartrate is used in the specific assay of which enzyme?

A

prostatic acid phosphatase

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21
Q

Retention of BSP can be used to measure?

A

liver function

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22
Q

What substrate and coenzyme are required to measure ammonia?

A

alpha-ketoglutarate and NADH

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23
Q

What is the main way that ammonia levels are kept within normal limits?

A

synthesis of urea from ammonia

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24
Q

Amylase is an enzyme that breaks down?

A

starch

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25
Q

Creatinine clearance is used to assess the rate of?

A

glomerular filtration

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26
Q

What is the most common exogenous substance used?

A

inulin

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27
Q

In the urease method, urea is converted to?

A

ammonium carbonate

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28
Q

Serum lipase levels are elevated in diseases of the?

A

pancreas

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29
Q

Diacetyl monoxime reacts with what to produce a yellow product?

A

urea

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30
Q

What is the normal value for CK in males at 37C?

A

15-160 IU/L

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31
Q

Serum amylase might be expected to be increased in diseases of the?

A

pancreas

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32
Q

The Jaffe reaction is used to measure?

A

creatinine

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33
Q

Which enzyme is useful in the detection of insecticide poisoning?

A

pseudocholinesterase

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34
Q

What precaution must be taken with specimens to be used for blood ammonia determinations?

A

avoid ammonia forming in vitro, placed on ice, correct tube, tested within 15 minutes, kept closed

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35
Q

Increased levels of LD-4 and LD-5 are associated with?

A

liver/acute hepatic disease

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36
Q

What is the principle of the enzymatic method for measurement of ammonia?

A

uses enzyme glutamate dehydrogenase and the substrate alpha ketoglutarate reaction is followed by decrease in absorbance at 340 nm as NADPH converted to NADP

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37
Q

Which isoenzymes is detectable within 4-6 hours after a MI?

A

CK2 or CK-MB

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38
Q

What would hemolysis do to the results of a lactate dehydrogenase (LD) that is seen in a myocardial infarction (MI)?

A

elevate results; cannot freeze (falsely decreased)

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39
Q

Aspartate aminotransferase (AST) is elevated in diseases of the?

A

heart

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40
Q

Why would hemolyzed specimens not be used for acid phosphatase?

A

RBC contains acid phosphatase

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41
Q

Acid phosphatase is primarily associated with diseases of the?

A

prostate

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42
Q

What enzyme can be used in the detection of alcoholism and in the monitoring of patients in alcohol treatment centers?

A

GGT

43
Q

What test can differentiate between liver and bone origin of an elevated alkaline phosphatase?

A

GGT

44
Q

Increased levels of serum alkaline phosphatase can indicated diseases of the?

A

bone and liver

45
Q

The enzyme responsible for the reversible oxidation of lactic acid to pyruvic acid is?

A

LD

46
Q

What is the normal value for prostatic acid phosphatase (ACP)?

A

less than or equal to 2.1 ng/mL

47
Q

What is the end product of purine metabolism in man?

A

uric acid

48
Q

What is the composition Nessler’s reagent?

A

double iodide of potassium and mercury

49
Q

Which enzyme can be used to establish the presence of semen?

A

acid phosphatase

50
Q

Phenylketonuria results from a deficiency in which enzyme?

A

phenylalanine hydroxylase

51
Q

What is the substrate for the enzyme alanine aminotransferase (ALT)?

A

alanine and alpha-ketoglutamic acid

52
Q

What is the main factor that determines how much the level of an enzyme in serum increases?

A

extent and severity of damage to its tissues or cells of origin

53
Q

What is the correct order of migration of the creatine kinase (CK) isoenzymes starting with the slowest?

A

CK-MM, CK-MB, CK-BB

54
Q

What are the substrates for amylase in the dye-labeled substrate method?

A

starch and dye

55
Q

At what temperature should serum CK specimens be stored?

A

4C

56
Q

The major isoenzymes of lactate dehydrogenase come from the?

A

heart and the liver

57
Q

What is the normal value for serum BUN?

A

8-26 mg/dL

58
Q

What causes the BSP dye to turn from colorless to colored?

A

alkali medium

59
Q

What does SGOT stand for?

A

serum glutamic oxaloacetic transaminase

60
Q

Creatinine excretion correlates best with the?

A

muscle mass

61
Q

Which enzyme is the first to become elevated following a MI?

A

CK-MB

62
Q

what is the main use of ammonia measurements?

A

diagnose reyes syndrome and pending or existing hepatic coma

63
Q

What happens to the creatinine clearance value in renal disease?

A

decreases

64
Q

What substances can cause falsely elevated values in the Berthelot reaction?

A

increased ammonia levels, lipemic and icteric specimens

65
Q

Name three ways that can be used in the laboratory to measure the rate of an enzymatic reaction?

A

multiple point assay, kinetic, continuous monitoring

66
Q

What is the best anticoagulant to use for plasma specimens to be tested for lactate dehydrogenase?

A

heparin

67
Q

What is the order of migration for the isoenzymes of alkaline phosphatase (ALP)?

A

liver is the fastest, bone, placenta, intestinal

68
Q

What is the characteristic change in the isoenzyme of lactate dehydrogenase (LD) that is seen in a myocardial infarction (MI)?

A

LD-1 is greater than LD-2, LD flip

69
Q

Why are creatinine levels in the serum not a good indicator of early renal damage?

A

values are not above upper limit or normal until 1/2 to 2/3 of renal function is abnormal

70
Q

What is the biggest disadvantage of troponin as a cardiac marker?

A

remains in blood for 7-10 days so repeat infarctions cannot be detected

71
Q

What test is Nessler’s reagent used for?

A

BUN

72
Q

Which has more liver specificity, ALT or AST?

A

ALT

73
Q

In which organs is the activity of creatine kinase the greatest?

A

brain, heart, and skeletal muscle

74
Q

How does progressive muscular dystrophy affect AST and ALT levels?

A

increases AST and ALT levels

75
Q

What is the normal value for serum amylase at 37C?

A

95-290 IU/L

76
Q

What is the major CK isoenzyme of normal serum?

A

CK-MM

77
Q

What is the purpose of the PSP test and the p-aminohippurate test?

A

measure excretory capacity of the kidneys

78
Q

To what class of enzymes to amylase and lipase belong?

A

hydrolase

79
Q

What is the old name for AST?

A

SGOT

80
Q

What is the old name for CK?

A

CPK

81
Q

What does CPK stand for?

A

creatine phosphokinase

82
Q

What two isoforms of CK are used for the early detection of an MI?

A

CK-MM/MB1 and CK-MB/MB2

83
Q

What is the normal range of total serum bilirubin?

A

0.2-1.0 mg/dL

84
Q

Risk factors for coronary heart disease

A

smoking, hypertension, increased total cholesterol and LDL, decreased HDL, diabetes mellitus, age, obesity, physical inactivity, family history of premature CHD, left ventricular hypertrophy

85
Q

Which marker has been recognized for the earliest biochemical marker for AMI?

A

myoglobin

86
Q

List of biochemical markers for coronary heart disease

A

triglycerides, Lp(a), homocysteine, hs-CRP

87
Q

What is the most likely cause of pre hepatic bilirubin?

A

acute or chronic hemolytic anemias

88
Q

What is the normal range for conjugated bilirubin?

A

0.0-2.0 mg/dL

89
Q

What is the normal range for unconjugated bilirubin?

A

0.2-0.8 mg/dL

90
Q

In the Jendrassik-Grof method, what is the caffeine benzoate solubilizer used for?

A

Solubilizes the water-insoluble fraction of bilirubin

91
Q

What are some ideal characteristics of a cardiac marker?

A

rises soon after infarction, elevated over a sustained period of time, easy to measure, broad dynamic range for measurements, quick turnaround, diagnostic utility verified by clinical studies

92
Q

What is the most likely cause of hepatic bilirubin?

A

intrinsic liver disease or defect

93
Q

What is the most likely cause of post hepatic bilirubin?

A

biliary obstruction

94
Q

Why are high levels of bilirubin seen in infants?

A

infant deficiency of enzyme glucuronyl transferase

95
Q

What precautions need to be taken when processing bilirubin?

A

fasting specimen, hemolysis not acceptable, keep away from light, stable two days at RT, a week at 4C, indefinitely at -20C

96
Q

Low levels of which enzyme can cause a patient to be susceptible to prolonged apnea when exposed to certain types of anesthesia?

A

pseudocholinesterase

97
Q

What enzyme is normally elevated during pregnancy?

A

alkaline phosphatase

98
Q

What is the proper treatment of serum to be assayed for ACP?

A

acidified to a pH of below 6

99
Q

What is the substrate for alkaline phosphatase methods of analysis?

A

para-nitrophenolphosphate

100
Q

In the creatine kinase reaction, what is converted to what?

A

ATP converted to ADP

101
Q

What is the source of urease used in enzymatic methods for the determination of BUN?

A

Jack Bean meal

102
Q

In the creatinine method, a color develops when creatinine combines with?

A

alkaline picrate

103
Q

Strenuous exercise can cause an elevated?

A

CK

104
Q

In the performance of a creatinine clearance, when should the specimen for serum creatinine be collected in relation to the collection of the urine?

A

midway through urine collection and not longer than 24 hours before or after collection