Cardiac Enzymes

Question 1

Aspartate aminotransferase (AST) normal values

Answer 1

15-33 U/L

Question 2

Lactate dehydrogenase (LDH)

Answer 2

180-380 U/L

Question 3

AST implications

Answer 3

Following myocardial damage:
Onset of rise 12 hr
Peak rise 24 hr
Return to normal 4 days

Question 4

LDH implications

Answer 4

Following myocardial damage:
Onset of rise 12-24hr
Peak rise 72hr
Return to normal 5-14 days

Question 5

Creatinine kinase (CK) normal values

Answer 5

40-210U/L

Question 6

CK implications

Answer 6

Following myocardial damage:
Onset of rise 4-8 hr
Peak rise 24hr
Return to normal 3-4 days

(Not specific because damage to sk ms also increases CK values)

Question 7

%CKMB Normal values

Answer 7

0-6 %

Question 8

%CKMB implications

Answer 8

Elevation of both CK and CKMB with CKMB exceeding 5% of CK confirms diagnosis of MI

Question 9

Troponin 1 normal values

Answer 9

0.00-0.33 ug/L

Question 10

Troponin 1 implication

Answer 10

Following myocardial damage: Rises in 4-6 hr
Peak within 12 hr
Return normal 3-10 days