COMPLEMENT C4 - (S)

Test Code: C4

Alternate Name(s): C4, C4 Complement Serum, C4 Serum, Fourth Component of Complement

Useful for investigating an undetectable total complement (CH50), confirming hereditary angioedema (with low C1 inhibitor) and for assessing disease activity in systemic lupus erythematosus, proliferative  glomerulonephritis, rheumatoid arthritis, and autoimmune hemolytic anemia.in systemic lupus erythematosus (SLE).  Also used  for investigating an undetectable total complement (CH50) level.
 
Values should be used in conjunction with other laboratory and clinical findings.

 

_SH Immunology Test Requisition (R250-10-21)

Age (yrs)	g/L
0 - 2	0.113 – 0.391
3 – 4	0.110 – 0.419
5 – 9	0.073 – 0.337
10 – 14	0.114 – 0.367
15 – 18	0.103 – 0.469
Adult 19+	0.129 – 0.392

Pediatric reference values adopted from Garcia-Prat M, Vila-Pijoan G, Martos Gutierrez S, et al. Age-specific pediatric reference ranges for immunoglobulins and complement proteins on the Optilite™ automated turbidimetric analyzer. J Clin Lab Anal. 2018;32:e22420. https://doi.org/10.1002/jcla.22420.
 
Adult reference values adopted from Binding Site, Optilite C4 Kit, INS025.OPT, ver 11th August 2015.

Method of Analysis: Turbidimetry – Binding Site Optilite

Weekdays

Reportable Range: 0.006 – 1.800 g/L
 
Undetected antigen excess is a rare event but cannot be excluded. If these results do not agree with other clinical or laboratory findings, or if the sample is from a patient that has previously demonstrated antigen excess, the result must be checked by retesting at a higher sample dilution. Results should always be interpreted in conjunction with other laboratory tests and clinical evidence; any anomalies should be discussed with the laboratory.