Cardiac enzymes are (PGI):
In MI →cardiac enzymes elevatedare:
a. CK-MB →starts to rise at 4-6 hrs, peak at 12 hours and normal within 48-72 hrs.
b. AST(SGOT) →rise after l2hrs, peak on 1st or 2nd day, normal within 3 to 4 days
c. LDH →rises after l2hrs, peak after to 2 to 3 days, and remain elevated for a week or more
d. Troponin T and I →released within hours, and remains elevated for 7 to 10 days.
e. Cardiac specific troponin T (cTnT) and cardiac specific troponin I (cTnI) →preferred biochemical markers for MI and may remain elevated for 7 to 10 days after ST elevated MI.
i. Alk. Phosphatase → Is markedly elevated in obstructive jaundice
ii. SGPT (ALT) →markedly elevated in Hepatocellular damage.
a. Its iso-enzymes and their source of origin.
i. LDH —1 (H4) → Heart muscle
ii. LDH - 2 (H3 M1) →RBC
iii. LDH —3 (H2 M3) →Brain
iv. LDH — 4 (H1 M3) →Liver
v. LDH — 5 (M4) → Skeletal muscle
b. Normally LDH2 concentration is blood is greater than LDH- 1, but this pattern is reversed in MI, this is called “FLIPPED PATTERN”. The iso-enzymes are usually separated by CELLULOSE-ACETATE-ELECTROPHORESIS at pH 8.6.
c. Normal value of LDH in serum is 100-200 U/L. LDH level is 100 times more inside the RBC than plasma, and therefore minor amount of hemolysis will result in a false +ve test
d. LDH serum level is increased in a lot of condition: - eg. ↑ed in →MI, Hemolytic anemia, Hepatocellular damage, muscular dystrophy, carcinoma, leukemias, and any condition which causes necrosis of body cells. Since total LDH is increased in many condition, that is why, the study of isoenzymes LDH is of great importance.