CK-MB (synonyms: creatine kinase isoenzyme MB, creatine kinase myocardial type) is found primarily in the myocardium (heart muscle). It accounts for about six percent of creatine kinase.
CK-MB is used primarily in myocardial infarction diagnostics.
An increase in CK-MB can be expected after 3 to 12 hours after the onset of infarction. The maximum is between 12 and 24 hours after infarct onset. CK-MB usually returns to normal after 2 to 3 days.
The procedure
Material needed
- Blood serum; centrifuged to avoid hemolysis during prolonged sample transport.
Preparation of the patient
- Not known
Disruptive factors
- Dark-skinned individuals have higher levels (increased up to 1.5 times)
- Weight-loss preparations containing cheyenne pepper, bitter orange, and amphetamines may damage the myocardium and increase CK-MB levels via sympathetic activation.
- Avoid hemolysis. Adenylate kinase from erythrocytes (red blood cells) increases enzymatically measured CK and CK-MB.
Normal values
| Normal value in U/l (new reference range; measurement at 37 °C). | 0-25 |
| Normal value in U/l (old reference range; measurement at 25 °C). | 0-10 |
Indication
- Suspected myocardial infarction (heart attack) for early diagnosis and follow-up:
- Suitable for rough estimation of infarct size.
- Reveals reinfarction more reliably than TnT because CK-MB normalizes faster (after 2- 3 days) than TnT (after up to 10 days)
Interpretation
Interpretation of increased values
- Myocardial infarction (heart attack)
Interpretation of decreased values
- Not relevant to the disease
Further notes
- If myocardial infarction is suspected, the following laboratory parameters should be determined:
- Myoglobin
- Troponin T (TnT)
- CK-MB (creatine kinase myocardial type).
- CK (creatine kinase)
- Aspartate aminotransferase (AST, GOT)
- LDH (lactate dehydrogenase)
- HBDH (hydroxybutyrate dehydrogenase)