SST tube
0.5 mL serum
0.25 mL serum
Collect specimen in an SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate up to 48 hours.
Collect specimen in an SST tube. .
Daily, 24 hrs
2 hours
Immunoturbidimetric
Adult: 13-60 mg/dl
C4 is decreased when classical pathway of complement is hyperactivated. It is usually decreased in hypergammaglobulinemia, cryoglobulinemia, inborn C4 deficiency, active SLE, serum sickness, SBE, chronic active hepatitis, acute glomerulonephritis and rheumatoid arthritis, as well as in hereditary angioneurotic edema.
C4 comprises approximately 20% of the complement system. C4 is utilized only by the classical pathway, so that it is decreased only when this arm is hyperactivated. In diseases activating the alternate pathway alone, C4 levels will be normal. Total hemolytic activity (CH50), C3, and C4 are frequently decreased in a variety of conditions relating to immune complex formation. While many complement components are depressed with uremia, C4 is an exception and is elevated with uremia.
4498-2
86160
21944
Red top tube, Green top tube (heparin). [rev 8/03]
Minimum of 72 hours.