Exam4 Flashcards
1
Q
What is the substrate for the enzyme aspartate amino transferase (AST)?
A
aspartate and alpha ketoglutamic acid
2
Q
Creatinine is formed from the breakdown of?
A
creatine
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
4
Q
Increased ALT values are associated with diseases of the?
A
liver
5
Q
What is the normal value for serum AST at 37C?
A
5-35 IU/L
6
Q
Which anticoagulant should not be used for urease testing?
A
sodium fluoride
7
Q
What is the normal percentage of the CK-MB isoenzyme?
A
less than 6%
8
Q
What reagent is used in the measurement of uric acid?
A
phosphotungstic acid
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
10
Q
What is the most common endogenous substance used to assess the glomerular filtration rate?
A
creatinine
11
Q
Serum creatine kinase is most often elevated in disease of?
A
muscle tissue
12
Q
What is uremia?
A
urea in the blood
13
Q
Define international unit
A
quantity of enzyme that will catalyze the reaction of one µmol of substrate per minute
14
Q
What is the peak absorbance of reduced NAD (NADH)?
A
340 nm
15
Q
Which non-protein nitrogen component comprises the largest fraction of NPN in the blood?
A
urea/BUN
16
Q
Gout is caused by the deposition of what in the joints and other tissues?
A
uric acid
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
18
Q
What is the normal ratio of BUN to creatinine?
A
10:1 to 15:1
19
Q
PSP is removed from the blood by the?
A
kidney
20
Q
L-tartrate is used in the specific assay of which enzyme?
A
prostatic acid phosphatase
21
Q
Retention of BSP can be used to measure?
A
liver function
22
Q
What substrate and coenzyme are required to measure ammonia?
A
alpha-ketoglutarate and NADH
23
Q
What is the main way that ammonia levels are kept within normal limits?
A
synthesis of urea from ammonia
24
Q
Amylase is an enzyme that breaks down?
A
starch
25
Creatinine clearance is used to assess the rate of?
glomerular filtration
26
What is the most common exogenous substance used?
inulin
27
In the urease method, urea is converted to?
ammonium carbonate
28
Serum lipase levels are elevated in diseases of the?
pancreas
29
Diacetyl monoxime reacts with what to produce a yellow product?
urea
30
What is the normal value for CK in males at 37C?
15-160 IU/L
31
Serum amylase might be expected to be increased in diseases of the?
pancreas
32
The Jaffe reaction is used to measure?
creatinine
33
Which enzyme is useful in the detection of insecticide poisoning?
pseudocholinesterase
34
What precaution must be taken with specimens to be used for blood ammonia determinations?
avoid ammonia forming in vitro, placed on ice, correct tube, tested within 15 minutes, kept closed
35
Increased levels of LD-4 and LD-5 are associated with?
liver/acute hepatic disease
36
What is the principle of the enzymatic method for measurement of ammonia?
uses enzyme glutamate dehydrogenase and the substrate alpha ketoglutarate reaction is followed by decrease in absorbance at 340 nm as NADPH converted to NADP
37
Which isoenzymes is detectable within 4-6 hours after a MI?
CK2 or CK-MB
38
What would hemolysis do to the results of a lactate dehydrogenase (LD) that is seen in a myocardial infarction (MI)?
elevate results; cannot freeze (falsely decreased)
39
Aspartate aminotransferase (AST) is elevated in diseases of the?
heart
40
Why would hemolyzed specimens not be used for acid phosphatase?
RBC contains acid phosphatase
41
Acid phosphatase is primarily associated with diseases of the?
prostate
42
What enzyme can be used in the detection of alcoholism and in the monitoring of patients in alcohol treatment centers?
GGT
43
What test can differentiate between liver and bone origin of an elevated alkaline phosphatase?
GGT
44
Increased levels of serum alkaline phosphatase can indicated diseases of the?
bone and liver
45
The enzyme responsible for the reversible oxidation of lactic acid to pyruvic acid is?
LD
46
What is the normal value for prostatic acid phosphatase (ACP)?
less than or equal to 2.1 ng/mL
47
What is the end product of purine metabolism in man?
uric acid
48
What is the composition Nessler's reagent?
double iodide of potassium and mercury
49
Which enzyme can be used to establish the presence of semen?
acid phosphatase
50
Phenylketonuria results from a deficiency in which enzyme?
phenylalanine hydroxylase
51
What is the substrate for the enzyme alanine aminotransferase (ALT)?
alanine and alpha-ketoglutamic acid
52
What is the main factor that determines how much the level of an enzyme in serum increases?
extent and severity of damage to its tissues or cells of origin
53
What is the correct order of migration of the creatine kinase (CK) isoenzymes starting with the slowest?
CK-MM, CK-MB, CK-BB
54
What are the substrates for amylase in the dye-labeled substrate method?
starch and dye
55
At what temperature should serum CK specimens be stored?
4C
56
The major isoenzymes of lactate dehydrogenase come from the?
heart and the liver
57
What is the normal value for serum BUN?
8-26 mg/dL
58
What causes the BSP dye to turn from colorless to colored?
alkali medium
59
What does SGOT stand for?
serum glutamic oxaloacetic transaminase
60
Creatinine excretion correlates best with the?
muscle mass
61
Which enzyme is the first to become elevated following a MI?
CK-MB
62
what is the main use of ammonia measurements?
diagnose reyes syndrome and pending or existing hepatic coma
63
What happens to the creatinine clearance value in renal disease?
decreases
64
What substances can cause falsely elevated values in the Berthelot reaction?
increased ammonia levels, lipemic and icteric specimens
65
Name three ways that can be used in the laboratory to measure the rate of an enzymatic reaction?
multiple point assay, kinetic, continuous monitoring
66
What is the best anticoagulant to use for plasma specimens to be tested for lactate dehydrogenase?
heparin
67
What is the order of migration for the isoenzymes of alkaline phosphatase (ALP)?
liver is the fastest, bone, placenta, intestinal
68
What is the characteristic change in the isoenzyme of lactate dehydrogenase (LD) that is seen in a myocardial infarction (MI)?
LD-1 is greater than LD-2, LD flip
69
Why are creatinine levels in the serum not a good indicator of early renal damage?
values are not above upper limit or normal until 1/2 to 2/3 of renal function is abnormal
70
What is the biggest disadvantage of troponin as a cardiac marker?
remains in blood for 7-10 days so repeat infarctions cannot be detected
71
What test is Nessler's reagent used for?
BUN
72
Which has more liver specificity, ALT or AST?
ALT
73
In which organs is the activity of creatine kinase the greatest?
brain, heart, and skeletal muscle
74
How does progressive muscular dystrophy affect AST and ALT levels?
increases AST and ALT levels
75
What is the normal value for serum amylase at 37C?
95-290 IU/L
76
What is the major CK isoenzyme of normal serum?
CK-MM
77
What is the purpose of the PSP test and the p-aminohippurate test?
measure excretory capacity of the kidneys
78
To what class of enzymes to amylase and lipase belong?
hydrolase
79
What is the old name for AST?
SGOT
80
What is the old name for CK?
CPK
81
What does CPK stand for?
creatine phosphokinase
82
What two isoforms of CK are used for the early detection of an MI?
CK-MM/MB1 and CK-MB/MB2
83
What is the normal range of total serum bilirubin?
0.2-1.0 mg/dL
84
Risk factors for coronary heart disease
smoking, hypertension, increased total cholesterol and LDL, decreased HDL, diabetes mellitus, age, obesity, physical inactivity, family history of premature CHD, left ventricular hypertrophy
85
Which marker has been recognized for the earliest biochemical marker for AMI?
myoglobin
86
List of biochemical markers for coronary heart disease
triglycerides, Lp(a), homocysteine, hs-CRP
87
What is the most likely cause of pre hepatic bilirubin?
acute or chronic hemolytic anemias
88
What is the normal range for conjugated bilirubin?
0.0-2.0 mg/dL
89
What is the normal range for unconjugated bilirubin?
0.2-0.8 mg/dL
90
In the Jendrassik-Grof method, what is the caffeine benzoate solubilizer used for?
Solubilizes the water-insoluble fraction of bilirubin
91
What are some ideal characteristics of a cardiac marker?
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
What is the most likely cause of hepatic bilirubin?
intrinsic liver disease or defect
93
What is the most likely cause of post hepatic bilirubin?
biliary obstruction
94
Why are high levels of bilirubin seen in infants?
infant deficiency of enzyme glucuronyl transferase
95
What precautions need to be taken when processing bilirubin?
fasting specimen, hemolysis not acceptable, keep away from light, stable two days at RT, a week at 4C, indefinitely at -20C
96
Low levels of which enzyme can cause a patient to be susceptible to prolonged apnea when exposed to certain types of anesthesia?
pseudocholinesterase
97
What enzyme is normally elevated during pregnancy?
alkaline phosphatase
98
What is the proper treatment of serum to be assayed for ACP?
acidified to a pH of below 6
99
What is the substrate for alkaline phosphatase methods of analysis?
para-nitrophenolphosphate
100
In the creatine kinase reaction, what is converted to what?
ATP converted to ADP
101
What is the source of urease used in enzymatic methods for the determination of BUN?
Jack Bean meal
102
In the creatinine method, a color develops when creatinine combines with?
alkaline picrate
103
Strenuous exercise can cause an elevated?
CK
104
In the performance of a creatinine clearance, when should the specimen for serum creatinine be collected in relation to the collection of the urine?
midway through urine collection and not longer than 24 hours before or after collection
