Quick Review Cards for Medical Laboratory Science

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Enzymes of Clinical Significancecontinued Clinical Chemistry Review 100


Lactate
dehydrogenase (LD)

Creatine kinase (CK)

Amylase (AMS)

Lipase (LPS)

Glucose-6-phosphate
dehydrogenase (G6PD)

ENZYME TISSUE(S) CLINICAL SIGNIFICANCE OTHER

All. Highest in liver,
heart, skeletal
muscle, RBCs

Cardiac muscle, skele-
tal muscle, brain

Salivary glands,
pancreas

Pancreas

RBCs

↑with AMI, liver disease, per-
nicious anemia

↑with AMI, muscular
dystrophy

↑in acute pancreatitis, other
abdominal diseases, mumps

↑in acute pancreatitis

Inherited deficiency can lead
to drug-induced hemolytic
anemia

Catalyzes lactic acid ¤ pyruvic acid. Avoid
hemolysis. Unstable. Store at 25ºC, not 4ºC.
Highest levels with pernicious anemia. Some
anticoagulants interfere.

Catalyzes phosphocreatine + ADP ¤ creatine
+ ATP. Most sensitive enzyme for skeletal
muscle disease. Highest levels with muscular
dystrophy. Inhibited by all anticoagulants ex-
cept heparin. ↑with physical activity, IM injec-
tions. CK-MB isoenzyme used in Dx of AMI.

Breaks down starch to simple sugars. In acute
pancreatitis, levels ↑2–12 hr after attack,
peak at 24 hr, return to normal in 3–5 days.

Breaks down triglycerides into fatty acids &
glycerol. Levels usually parallel amylase, but
may stay ↑longer. More specific than amylase
for pancreatic disease.

Measured in hemolysate of whole blood.
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