Creatine Kinase (CK, CPK)

Muscle damage check

Creatine kinase (CK), also called CPK, is an enzyme found mainly in skeletal muscles, with smaller amounts in the heart and brain. When muscle is injured or inflamed, CK leaks into the blood and the level rises. The test helps a doctor find and follow muscle damage, whether from injury, heavy exercise, inflammation, inherited muscle conditions or some medicines.

• To look into muscle pain, weakness or dark urine
• When muscle aches develop while taking a statin (a cholesterol medicine)
• After a crush injury, a fall, a seizure or very strenuous exercise
• To look for muscle inflammation (myositis) or an inherited muscle condition

There is no need to fast. Avoid hard exercise or heavy physical work in the days before the test, as it can raise CK. Tell your doctor about any recent injection into a muscle, fall or injury, and keep taking your usual medicines unless your doctor advises otherwise.

Sample

Blood sample

How it works

A small blood sample is drawn from a vein in your arm when the collector visits, which takes a few minutes. If you have very dark or cola-coloured urine with muscle pain, seek urgent medical help rather than waiting for a routine test.

Report

Within 24 hours of collection.

A raised CK shows that muscle has been damaged or strained, but not why. Mild rises are common after exercise, injections or injury, while very high levels can occur with severe muscle breakdown (rhabdomyolysis), which can harm the kidneys. CK levels are naturally higher in people with more muscle. Your doctor will interpret the result together with your symptoms, medicines and other tests, such as kidney function.

One test: Creatine Kinase (CK, CPK), from one blood sample.