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.
