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Muscles

Insight into your CK level.

CK is an enzyme released when muscle tissue is damaged. It rises after heavy exertion and can be raised with persistent muscle complaints.

Also known as: creatine kinase, CPK, creatine phosphokinase, CK level

Results typically within 2 working days
No referral required
800+ collection points

Personal assessment by our BIG-registered doctors

How it works?

How Bloodworks works

  1. Order online

    Choose your package and preferred location

  2. Receive your lab form

    Within 24 hours by email, with appointment planner

  3. Schedule your blood draw

    Or choose a walk-in location

  4. Blood draw

    Takes just a few minutes

  5. Receive your report

    Securely, typically within 2 working days from our physicians

Background

What is creatine kinase?

Creatine kinase, or CK, is an enzyme found mainly in muscle tissue: in skeletal muscle, in heart muscle and in smaller amounts in the brain. It plays a role in supplying energy to the muscle cell. When a muscle cell is damaged, CK leaks into the blood and the level rises. How far it rises says something about the extent of the damage, not about its location or cause.

That makes CK a sensitive but broad marker. A markedly raised value nearly always traces back to muscle, but does not in itself say whether that is due to hard training, a fall, a medicine or an underlying muscle condition. The result gains meaning from what you did in the preceding days and what symptoms you have.

In brief

Muscle enzyme

Mainly in skeletal muscle, also in heart muscle

Leaks on damage

Released when muscle cells are damaged

Exertion weighs heavily

Rises sharply after unusual or heavy training

Broad, not specific

Shows damage, not the location or the cause

Common reasons to test

When can insight into your CK be valuable?

Below are some situations in which measuring CK can provide insight.

With persistent muscle complaints

Muscle pain or weakness that does not settle can be a reason to check whether muscle damage is measurable.

On cholesterol lowering medication

Statins cause muscle complaints in a small group. CK shows whether muscle damage accompanies them. Always discuss your medication with your doctor.

After heavy training

Unusual or very intense exertion raises CK for days. Athletes use the value to track recovery.

What your result means

CK too high: what your value means

CK is expressed in units per litre (U/L). The laboratory states the reference values that apply there; these differ between men and women and are naturally higher in people with a lot of muscle mass. For a usable result it helps to avoid unusually heavy exertion in the 48 hours before the draw.

Low / below reference

A low value

A low CK rarely gives cause for concern and fits with limited muscle load. Our doctor provides explanation and context with your result.

Within reference

A normal value

A CK within the laboratory reference values fits with no measurable muscle damage at the time of the draw.

Above reference

A raised value

A raised CK most often fits with exertion in the days before the draw. If it stays raised without that explanation, or if it is a marked rise with symptoms, assessment by your GP is appropriate. Our doctor indicates in your report what fits your result.

How we interpret your result

Our doctors assess your CK against the laboratory reference values and your personal context: what you did in the days before the draw, your muscle mass, your symptoms and any medication. Without that context a single CK value is hard to interpret.

Related tests

Often combined with CK.

A single marker gives one perspective. For a broader picture you can combine CK with a theme package or related markers.

+ €29 blood draw fee per orderFree from €225

Frequently asked questions

Everything you want to know

Do I need to fast for a CK test?

Fasting is not needed. More important is to avoid unusually heavy or unfamiliar exertion in the 48 hours before the draw: that can raise the value considerably and makes the result harder to interpret.

Does a raised CK mean something is wrong with my muscles?

Not necessarily. The most common explanation is exertion in the preceding days. CK shows that muscle tissue has been damaged, not what caused it. A persistently raised value without a clear explanation should be assessed by your GP.

Does CK say anything about my heart?

Not reliably. CK is also present in heart muscle, but other, more specific tests are used to assess the heart. If you have symptoms that could point to the heart, contact your GP or out-of-hours service straight away rather than waiting for a result.

I take a statin and have muscle pain. Can I stop by myself?

No. Always discuss this first with the doctor who prescribed it. A CK measurement can provide information, but the decision about your medication belongs with your own doctor.

Ready for insight into your CK level?

You receive your CK level with a personal explanation from a doctor, usually within 2 working days. No referral needed.

Order CK

Want to test multiple markers at once?

Combine CK with other markers via Bloodworks Select. The blood draw and collection fee is charged once per order, and is waived from €225.

Open Bloodworks Select →

40,-

+ €29 blood draw fee

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