CH50 is an assay for functional integrity of the complement system and is used to monitor overall activity in complement consuming diseases. It is sometimes more sensitive than either C4 or C3. Its main value, however, is as a screen for complete defects of components other than C3 and C4. If the latter are normal and the CH50 is absent or very low, then it suggests a defect in some other complement component, and calls for a more complete evaluation of the complement system.
Sample requirement: 1 mL serum, separated from the clot within one hour of venepuncture. For optimum assessment the sample should be received within twenty-four hours of separation. Transportation at ambient temperature for this length of time rarely produces artefact. If longer transport times are anticipated, transportation at -20C is recommended.
Reference range: Reference ranges are method dependent. Users should consult the PRU Handbook and the relevant assay laboratory.
Centres offering this assay:
London St George’s Hospital PRU Diagnostic Service
Sheffield Northern General’s PRU Diagnostic Service