Cardiac Markers

Creatine Kinase (CK)

Normal range 30–200 U/L (0.5–3.34 µkat/L SI). Specimen: Serum.

Also known as: CPK, total CK.

30–200 U/LCritical: read below

Reference range

ConventionalU/L

30200

SIµkat/L

0.53.34

Specimen	Serum
Conventional range	30–200 U/L
SI range	0.5–3.34 µkat/L
Conversion factor	×0.0167 (conventional → SI)
Critical value	Marked elevation (thousands) suggests rhabdomyolysis
Panel	Cardiac Markers

Convert any Creatine Kinase (CK) result between units on the unit converter.

What is the normal range for Creatine Kinase (CK)?

The standard teaching reference range for Creatine Kinase (CK) is 30–200 U/L in conventional units, or 0.5–3.34 µkat/L in SI units. This value is measured in serum.

A commonly taught critical (panic) value is Marked elevation (thousands) suggests rhabdomyolysis. Critical results are reported to the provider immediately under your facility's policy.

Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population — always use the range printed on the actual result.

Above the range

Common causes of a high Creatine Kinase (CK)

Muscle injury or rhabdomyolysis
Myocardial infarction
Intense exercise
Statin-related myopathy

Below the range

Common causes of a low Creatine Kinase (CK)

Low muscle mass

At the bedside

Nursing considerations

Total CK rises with any muscle damage; fractionate to CK-MB for cardiac specificity.
Very high CK threatens the kidneys — monitor renal function and hydrate.

Study aid

Your notes on Creatine Kinase (CK)

Your notes

Same panel

More Cardiac Markers tests

B-type Natriuretic Peptide (BNP)< 100 (heart failure unlikely) pg/mL CK-MB< 5 (or < 5% of total CK) ng/mL Myoglobin25–72 ng/mL NT-proBNP< 125 (age < 75); < 450 if older pg/mL Troponin I< 0.04 (assay-dependent) ng/mL Troponin T< 0.01 (assay-dependent) ng/mL