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Factor H level

Lab Section:  Sendout Reference  
Lab Location:  Sendout
Reference Lab: ARUP 
Test ID: LAB2963 
Methodology: Quantitative Radial Immunodiffusion
Schedule: Variable testing schedule
Reported: 30 days
Specimen Requirements:  Collection: 3.0 mL Blood in a Lavender Top Tube.
Pediatric volume: 1 mL.
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.
Transport: Frozen..
Handling: Centrifuge at room temp within one hour of collection. As soon as possible freeze the cell-free plasma on dry ice or at -70C.
Unacceptable conditions: Thawed specimens
Stability: Ambient: Unacceptable; Refrigerated: Unacceptable: Frozen: 1 year


Clinical Indications: Factor H is a member of the regulators of complement activation family and is a complement control protein. Its principal function is to regulate the Alternative Pathway of the complement system, ensuring that the complement system is directed towards pathogens and does not damage host tissue. Factor H regulates complement activation on self cells by possessing both cofactor activity for the Factor I mediated C3b cleavage, and decay accelerating activity against the alternative pathway C3 convertase, C3bBb. Factor H protects self cells from complement activation but not bacteria or viruses in that it binds to glycoasmioglycans (GAGs) that are present on host cells but not pathogen cell surfaces. Due to the central role that factor H plays in the regulation of complement, there are a number of clinical implications arising from aberrant factor H activity. Overactive factor H may result in reduced complement activity on pathogenic cells - increasing susceptibility to microbial infections. Underactive factor H may result in increased complement activity on healthy host cells - resulting in autoimmune diseases. It is not surprising therefore that mutations or single nucleotide polymorphisms (SNPs) in factor H often result in pathologies. Moreover the complement inhibitory activities of factor H, and other complement regulators, are often used by pathogens to increase virulence.

Reference Interval:  See patient report or consult reference laboratory website.
CPT Code(s): 86160
Last Changed: 11/23/2016 23:20:36
Last Reviewed: 11/23/2016 23:21:02