Laboratory Test Information Guide

Details for C1qrs, Serum

Test Name: C1qrs, Serum
Alternate Name(s): C1qrs components
C1 complement component group test
C1qrs levels
Laboratory: Clinical Immunology
Specimen Type: Both plasma and serum are required
5 mL Gold top Vacutainer tube or 6 mL Red top Vacutainer tube and a 5 mL Lavender top (EDTA plasma)

0-2 yrs: Red 0.5pk. and Purple 0.5pk
2-10 yrs: 2 mL Red and Purple top
Collection Information: C1qrs is a group test comprised of C1q, C1r, C1s.

C1r can be ordered individually test code C1R.
C1s can be ordered individually test code C1S.
C1q can be ordered individually test code C1Q.
See interpretive comments.

Request CH50 (TCOM) on the same sample.
Record collection time.
Send the sample to the laboratory ASAP.
Mix lavender tube well after procurement.
Minimum plasma volume is 2 mL divided into 2 aliquots
Test Schedule: Referred out monthly.
Total complement CH50 is performed as a screen to determine if the component assay is required.
Turnaround time from when specimen
is received in testing laboratory:
40 days
Reference Range: C1q level: 83-125 mg/L
C1r level: 61-162 % of STD
C1s level: 59-297 % of STD
Effective Date: 2010-01-11
Revised Date: 2020-05-20
Critical Value:  
Interpretive Comments: The group test C1qrs includes C1q, C1r, C1s protein quantitation. It does not evaluate function.

This test does NOT include C1 esterase inhibitor or C1 esterase inhibitor functional assay. Order these tests separately. See Lab Test Information Guide entry for C1IN.

Both low C1IN levels, C1IN function and decreased C1q protein concentration are associated with acquired angioedema.

The component C1q test does NOT evaluate circulating immune complexes (IC).

Total complement (TCOM, CH50) is a screen for classical pathway function.The component assay is a quantitative evaluation of the concentration of each component but does not evaluate the functional activity of the component.

See also CCOMPG.
Special Processing: Centrifuge lavender tube (plasma) at room temperature as soon as possible after collection. Aliquot the plasma into 2 storage tubes and freeze as rapidly as possible.
Allow the filled red top tube to clot at 22-37o for 30-60 minutes. Centrifuge at room temperature. Aliquot into storage tube and freeze as soon as possible. Store at -20oC (preferably -70oC).

For CH50: 1 Aliquot (serum)
For C1qrs: 2 Aliquots (plasma)
Comments: This test is available exclusively to SJHC/LHSC physicians.

C1QRS is a group test that includes C1q, C1r, and C1s.
Also order TCOM (CH50).

Total complement is assayed first to determine if the components evaluation is necessary. If the total complement is within the normal range, the component(s) is resulted as "not indicated".
Method of Analysis: Radial Immunodiffusion (RID)
Critical Information Required:  
Storage & Shipment: LHSC (SRA to Immunology Laboratory) Ship frozen on ice packs. Avoid freeze/thaw cycles.
System Codes: 
Referred To: Components are referred to:

National Jewish Medical and Research Center
1400 Jackson St.,
Denver, Colorado

Questions? Comments? Contact Laura Gopaul