Creatine Kinase (CK) CPT: 82550

Special Instructions

State patient’s sex on the request form.

Expected Turnaround Time

Within 1 day

Specimen Requirements


Serum (preferred) or plasma


2 mL

Minimum Volume

0.4 mL (Note: This volume does not allow for repeat testing.)


Red-top tube, gel-barrier tube, or green-top (heparin) tube


Separate serum or plasma from cells. Avoid prolonged contact of serum or plasma with red cells.

Storage Instructions

Maintain specimen at room temperature.

Stability Requirements

Temperature Period
Room Temperature 4 hours
Refrigerated 5 days
Frozen 1 month
Freeze/thaw/ cycles Stable x 3

Patient Preparation

Avoid exercise before venipuncture. Increases may be anticipated in the immediate postoperative period following surgical procedures involving incision through muscle.

Patient Information

To detect and monitor muscle damage; to help diagnose conditions associated with muscle damage; for heart attack detection, this test has been largely replaced by troponin T and I – markers more specific to cardiac tissue; however, it may sometimes be used to help detect a second or subsequent heart attack.

When you have muscle weakness, muscle aches, and/or dark urine and your healthcare practitioner suspects muscle damage; sometimes to monitor for muscle injury resolution or persistence.

A blood sample drawn from a vein in your arm.