Pathology/Lab Coding Alert

Question: The lab performed four CK level tests for an ER patient within a 24-hour period, beginning when the patient was first admitted, then every six hours, with rising levels noted. What is the correct diagnosis and procedure coding?

Louisiana Subscriber

Answer: The correct code for the creatine kinase (CK) lab test is 82550 (Creatine kinase (CK), (CPK); total). You should list one unit for each of the four separate tests.

Repeat: Because the lab repeated the same CK test six hours apart, you should append modifier 91 (Repeat clinical diagnostic laboratory test) to each test subsequent to the first.

The elevating CK levels leads to diagnosis code R74.8 (Abnormal levels of other serum enzymes).

Clinicians may order repeat lab tests for CK in patients with myocardial infarction (MI) symptoms. Typically, CK levels increase around four to eight hours after an infarction occurs. Within about 24 hours, the CK level peaks. After roughly three days, the CK levels return to normal.

You should not assume a patient with elevated CK levels has had an MI though. Only report an MI code if the medical record indicates the patient has had an MI.