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HelpTest ID CKMB Creatine Kinase (CK) MB Isoenzyme, Serum
Useful For
Serial quantitation of serum creatine kinase MB (CKMB) levels, often performed at admission and 8-hours, 16-hours, and 24-hours after admission, has traditionally been used as an aid in the diagnosis of myocardial injury
May be useful if the initial troponin determination is abnormal or if a hospitalized patient has a suspected reinfarction
Method Name
Electrochemiluminescent Immunoassay
Reporting Name
Creatine Kinase(CK) MB Isoenzyme, SSpecimen Type
SerumCollection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen (preferred) | 90 days |
| Refrigerated | 7 days | |
| Ambient | 12 hours |
Clinical Information
There are 3 isoenzymes of creatine kinase (CK)-BB, -MM, and -MB. The primary source of CKMB is myocardium, although it is also found in skeletal muscle. CKMB levels increase with myocardial damage. Extreme elevations of CKMB can also be associated with skeletal muscle cell turnover as in polymyositis and to a lesser degree in rhabdomyolysis. It can also be elevated in cases of carbon monoxide poisoning, crush injuries, pulmonary embolism, hypothyroidism, and muscular dystrophy.
While CKMB has been replaced by troponin assays in the workup of many patients with acute chest pain, CKMB may be useful if the initial troponin determination is abnormal or if a hospitalized patient has a suspected reinfarction.
Reference Values
Males: ≤7.7 ng/mL
Females: ≤4.3 ng/mL
Cautions
Creatine kinase MB (CKMB) values that exceed 50% of the total CK, probably reflect unusual beta-subunit synthesis since the heart muscle rarely exceeds 30% CKMB.
The newer sandwich assays for CKMB have eliminated the confusion seen with older methodologies, but may result in the inability to detect some infrequent contributions to total CK (eg, macro and mitochondrial forms).
In patients receiving treatment with high biotin doses (>5 mg/day) there should be an interval of at least 8 hours between the last biotin administration and the collection of the specimen as biotin interferes with the assay.
Day(s) Performed
Monday through Sunday; Continuously
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82553