Page 109 - Clinical Biochemistry

Types:

1-Enzyme 2- Protein 3- Lipid and lipoprotein

AST Myoglobin TC, TAG

CK Troponin LDLC, HDLC, LDLC/HDLC index

LDH

Enzyme markers
Enzymes are the most common available tests used as diagnostic indicator for cardiac disease.
1- Aspartate aminotransferase (AST):
-AST is present in cardiac and skeletal muscle, liver, kidney –etc.
-It is increased and proportional to extent of cardiac damage, hepatocellular disorders and
skeletal involvement.
-Begins to rise within 6-8 hr., makes a peak at 24 hr.
-Generally, returns to normal within 5 days.
2- Creatine kinase (CK):
It consists of 2 protein subunit M, B which combine to form 3 isoenzymes:
• CK-BB which is specific for brain tissue.
• CK-MB which is specific for heart tissue.
• CK-MM which is specific for skeletal muscle tissue.
CK-MB isoenzyme: CKMB1 and CKMB2.
Laboratory determination of CK-MB is the sum and it is an early marker for AMI.
Creatine kinase: CK-MB
In normal population CK-MB < 6% Total CK
CKMB Index= (CKMB /total CK) x100
Sensitive marker with rapid rise & fall:
Serum CK-MB levels rise within 2~8 hours after AMI.