Sign in →

Test Code CH50 Complement, Total, Serum

Important Note

Immediately after drawing the specimen, place the tube on wet ice.

Reporting Name

Complement, Total, S

Useful For

Detection of individuals with an ongoing immune process


First-order screening test for congenital complement deficiencies

Specimen Required

Patient Preparation: Fasting preferred.

Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Immediately after drawing the specimen, place the tube on wet ice.

2. Spin down and separate serum from clot.

3. Immediately freeze specimen.

Seattle Children's Hospital Note:

Collect 2.0 mL whole blood in a Red Top.

Reject due to: SST, specimens stored refrigerated or ambient.

Specimen Type

Serum Red

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Frozen 14 days

Day(s) and Time(s) Performed

Monday through Saturday; 3 p.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

Automated Liposome Lysis Assay

Method Description

An automated method is performed using liposomes as the target for the serum complement system. The dinitrophenyl (DNP)-labeled liposomes are sensitized with antibody to DNP. Serum complement causes lysis and release of entrapped glucose-6-phosphate dehydrogenase. Glucose-6-phosphate dehydrogenase reacts with glucose-6-phosphate and nicotinamide adenine dinucleotide (NAD). NAD is reduced to reduced nicotinamide adenine dinucleotide (NADH) and the conversion is measured at 340 nm. The assay correlates with the CH50 assay based on sheep RBC lysis, has lower variability, and is simpler to perform.(Package insert: Wako Autokit CH50. Wako Pure Chemical Industries, Ltd., 08/2007; Yamamoto S, Kubotsu K, Kida M, et al: Automated homogeneous liposome-based assay system for total complement activity. Clin Chem 1995;41:586-590)

Reference Values

≥16 years: 30-75 U/mL

Reference values have not been established for patients that are <16 years of age.

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
COM Complement, Total, S 4532-8


Result ID Test Result Name Result LOINC Value
COM Complement, Total, S 4532-8

Reject Due To


Mild OK; Gross reject


Mild OK; Gross OK


Mild OK; Gross OK


Serum gel tube


If not ordering electronically, complete, print, and send a General Request Form (T239) with the specimen (