Cardiac Enzyme Studies

CK (Creatine Kinase), CPK (Creatine Phosphokinase), Creatine Kinase (CK), Creatine Phosphokinase (CPK), Creatine Phosphokinase-MB Isoenzyme (CPK-MB), Heart Attack Enzymes, Lactic Acid Dehydrogenase (LDH), LDH-1 (Lactate Dehydrogenase Isoenzymes)

Results

Cardiac enzyme studies measure the levels of the enzyme creatine phosphokinase (CPK, CK) and the protein troponin (TnI, TnT) in the blood.

Test results are usually available within an hour.

Values and units for reporting the results of cardiac enzyme tests vary considerably from lab to lab. The values listed below can be used as a general guide. Check with your lab or doctor for specific values.

Troponin (TnI and TnT)

Normal:	TnI: Less than 0.3 micrograms per litre (mcg/L) TnT: Less than 0.1 mcg/L
Abnormal:	Elevated troponin may be present when you have heart muscle injury. Blood levels of troponin typically rise within 4 to 6 hours after a heart attack, reach their highest levels within 10 to 24 hours, and fall to normal levels within 10 days.

 

Total CPK (creatine phosphokinase)

Normal:	Men:	55–170 international units per litre (IU/L)
	Women:	30–135 IU/L
Abnormal:	CPK levels generally rise within 4 to 8 hours after a heart attack, reach their highest levels within 12 to 24 hours, then return to normal within 3 to 4 days.

 

CPK-MB

Normal:	Less than 3.0 nanograms per millilitre (ng/mL) (0% of total CPK)
Abnormal:	CPK-MB is found in large amounts in the heart muscle. A CPK-MB greater than 3.0 ng/mL may be present when you have muscle damage caused by a heart attack. Blood levels of CPK-MB typically rise within 2 to 6 hours after a heart attack, reach their highest levels within 12 to 24 hours, and fall to normal levels within 3 days.
	An ongoing high level of CPK-MB levels after 3 days may mean that a heart attack is progressing and more heart muscle is being damaged.

 

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Author:	Douglas Dana Maria G. Essig, MS, ELS Robin Parks, MS	Last Updated: November 2, 2007
Medical Review:	Anne C. Poinier, MD - Internal Medicine E. Gregory Thompson, MD - Internal Medicine Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
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