Several conditions causing elevation of serum CK-MB and CK-BB

Area of Science:

• Biochemistry
• Clinical Chemistry
• Enzymology

Background:

• Creatine kinase (CK) is primarily found in skeletal muscle and myocardium.
• Organ destruction theoretically releases soluble enzymes, including CK, into circulation.
• CK isoenzymes (MB and BB) can indicate tissue damage beyond cardiac events.

Purpose of the Study:

• To investigate the presence and significance of creatine kinase isoenzymes (MB and BB) in serum following various destructive processes.
• To evaluate the diagnostic utility of CK isoenzymes in non-myocardial injury contexts.

Main Methods:

• Serum samples from 70 patients with various destructive processes were analyzed for CK isoenzyme activity.
• Quantification of creatine kinase MB (CK-MB) and creatine kinase BB (CK-BB) isoenzyme levels.
• Calculation of isoenzyme activity as a percentage of total CK activity.

Main Results:

• Creatine kinase MB isoenzyme was detected in 24% of patients, with activity ranging from 0.7% to 10% of total CK.
• Creatine kinase BB isoenzyme was detected in 17% of patients, with activity ranging from 0.4% to 18.6% of total CK.
• Significant levels of both MB and BB isoenzymes were observed in conditions other than myocardial injury.

Conclusions:

• The presence of CK-MB isoenzyme in serum does not exclusively indicate myocardial injury.
• Laboratory interpretation of CK isoenzyme assays requires caution, particularly with combined MB/BB assays.
• Diagnosis of myocardial injury should integrate CK-MB findings with comprehensive clinical and laboratory data.