Classical Pathway Haemolytic Complement Assay (CH50)

Immunology

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Description

CH50 is a measure of classical complement pathway activity. Activity was traditionally expressed as the reciprocal dilution of the serum sample required to achieve 50% lysis of a fixed amount of antibody-coated sheep erythrocytes [1,2]. Decreased CH50 values may be caused by consumption or a deficiency of one or more of the classical complement components. Complete defects of particular classical pathway components, such as C1/2/3/4/5-C8, usually result in a CH50 value of zero [3]. CH50 provides an initial screening tool for investigation of complement deficiency in individuals with symptoms such as recurrent sinopulmonary bacterial infections. Autoimmune complex disease, such as SLE, can result in classical complement pathway consumption or be associated to a primary complement deficiency [1].

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Indications

Complement deficiency / recurrent Neisserial infections.

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Sample Type

2mL Fresh Serum (Gel 5mL Yellow tube).
Samples should be separated within 2 hrs of venesection and stored at -20C.
Requests from outside Sheffield: freeze sample prior to dispatch and transport frozen sample at ambient temperature via Royal Mail or Courier (dry ice not required).

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Reference Range

23 - 46 U/mL.
Reference range established by in house verification of manufacturer specified range.

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Turnaround Time

Within 10 days

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Testing Frequency

Weekly

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External Notes

Fresh samples may be sent by overnight delivery. If there is going to be a delay in transporting the dample then 2mL Serum must be separated from unfrozen clotted blood within 1-2 hours of venesection and stored at -20�C as soon as possible. EDTA plasma samples should not be used as the chelation of calcium ions render some of the Complement components to be inactive.

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References

Mollnes, et al. Complement analysis in the 21st Century. 2007. Mol Imm. 44:3838-3849. [Ref 1]
PRU Handbook of Clinical Immunochemistry. 9th Ed. 2007. [Ref 2]
Wen L, Atkinson JP, Giclas PC. Clinical and laboratory evaluation of complement deficiency. J Allergy Clin Immunol. 2004. 113(4):585-593. [Ref 3]
Jaskowski TD, et al. Comparison of three different methods for measuring classical pathways complement activity. 1999. Clin Diag Lab Imm. 6:137-139.

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.