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Test Code C4FX C4 Complement, Functional, Serum

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum Red


Ordering Guidance


The total complement assay (COM / Complement, Total, Serum) should be used as a screen for suspected complement deficiencies before ordering individual complement component assays. A deficiency of an individual component of the complement cascade will result in an undetectable total complement level.

Specimen Required


Patient Preparation: Fasting preferred

Supplies: Sarstedt 5 mL Aliquot Tube (T914)

Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

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

2. Centrifuge and aliquot serum into plastic vial.

3. Immediately freeze specimen.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Frozen 14 days

Reference Values

22-45 U/mL

Day(s) Performed

Monday through Friday

CPT Code Information

86161

Report Available

1 to 3 days

Specimen Retention Time

14 days

Reject Due To

Gross hemolysis OK
Gross lipemia Reject
Gross icterus OK