Special Precautions/Comments:

Interferences: Prolonged transport or inappropriate sample handling can result in artefactually low CH50 values. Cryoglobulins may cause in vitro activation and reduce CH50 levels. Therefore low values should be checked on a second sample if complement component deficiency is suspected

Interpretation: Discuss with Clinical Scientists / Medical Staff

Additional Information:

Indication: Complement deficiency / recurrent Neisserial infections

Background  Information: 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].

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

Telephone Gateshead Lab: 0191.4456499 Option 4, Option 1