KidneyReported in U/LCreatine kinase (CK)
An enzyme that leaks from muscle when muscle is strained or injured. It is a different test from creatinine.
What it measures
Creatine kinase helps muscle cells recycle energy. A little circulates all the time. When muscle fibers are damaged, more enters the blood and the level rises. Strenuous exercise, an injection into muscle, or a fall can raise it for days. Creatinine, the kidney marker, is a separate molecule with a similar name. The two results answer different questions.
Why it is on the panel
A high CK explains muscle pain, a dark urine after extreme exertion, and some medicine side effects, including statin-related muscle symptoms. On a screening panel it also keeps you from confusing a muscle enzyme with a kidney problem.
How to read it
Compare CK with creatinine. A high CK and a normal creatinine points at muscle. A high creatinine and a normal CK points at filtration. If both are high after extreme exercise or dehydration, the story may be muscle injury that also stressed the kidneys. The 12-hour rest from strenuous exercise in the visit prep exists partly because of this test.
When it runs higher
Hard workouts, muscle injury, seizures, intramuscular injections, hypothyroidism, and some medicines raise CK. The rise after a race can be several times the interval and still settle. Chest-pain syndromes are a separate, urgent reason a CK (or a related cardiac marker) gets checked in an emergency setting.
When it runs lower
A low CK is uncommon and can be seen in people with low muscle mass, in hyperthyroidism, and in some chronic illnesses. It is rarely the result anyone acts on.
Before the draw
Skip strenuous exercise for at least 24 hours beforehand. A hard workout can raise creatine kinase for several days.
Same group
Other Kidney tests
How to use this page
This page explains what the measurement is for. It is educational. Your Healiam report includes the reference interval for your age and sex, and a clinician reads that result with your history, medicines, and the rest of the panel. Talk with a clinician before changing diet, supplements, or treatment because of a number on a report.
Creatine kinase
Creatine kinase is part of the full panel.
No referral or insurance required.
One preventive draw covers this measurement and the rest of the Healiam panel. CLIA-certified results come back in days.