All tests › Inflammation and immune system

Total complement (CH50)

Inflammation and immune system · also printed as CH50, CH100, Total haemolytic complement, Complement function, Complement CH50

Typical UK adult rangeNo single typical range

No fixed range; the lab prints its own, and the important finding is an absent or very low value.

What this test measures

CH50 measures the combined activity of the whole complement system, a set of blood proteins that helps antibodies clear infection. A very low value points to one of the proteins being missing or used up.

Why doctors request it

Requested by immunologists in recurrent infections with certain bacteria and in lupus.

What commonly pushes it up

Inflammation of any kind

What commonly pushes it down

Active lupus and some kidney conditions that consume complement
An inherited deficiency of one component
A sample that was not frozen quickly

Everyday reasons for a value outside the range

Delayed handling lowers it
Units differ between labs

About the sample

Needs prompt freezing; the lab arranges this.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.