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Method Update for Ceruloplasmin, C3 and C4
The Department of Pathology & Laboratory Medicine will transition certain special chemistry tests (Ceruloplasmin, C3 Complement, C4 Complement) to a new instrument platform, the Optilite® (Binding Site). Reference intervals will be updated in accordance with manufacturer’s recommendations and internal laboratory validation. The following new adult serum reference intervals for C4 and ceruloplasmin were verified in 27 adult blood donors. The new reference interval for complement C3 was established in 63 adult blood donors.

Test Name Test Code Previous Adult Reference Interval
New Adult Reference Interval
C3 Complement
88-201 mg/dL
65-175 mg/dL
C4 Complement
16-47 mg/dL
13-39 mg/dL
22-58 mg/dL
20-60 mg/dL

There is a very small bias observed for C3 and C4 measured with the new assays when compared with the previous assays (<25%). The antibody used in the previous assay measured native C3 and conversion products C3c and C3d, whereas the antibody in the new assay is specific for C3c. When compared to an assay that recognizes native C3, assays specific to C3c may give slightly higher results after complete conversion of C3 to C3c. This difference is not considered to be clinically significant.

Effective date: May 5, 2021

Specimen requirement and testing information:

Specimen: Collect 4.0 mL blood in a red or gold top tube. Spin down and separate serum from cells as soon as possible, and within two hours of sample collection.

Test methodology: Turbidimetric

Test codes: C3BET, COMPC4, CERULO

Minimum stability† (after separation from cells):
Ambient: N/A
Refrigerated: 24 hours
Frozen: 8 days (No freeze-thaw)

† Some tests may have extended stability beyond stated minimum limits. See directory for details.

Turnaround time (TAT):
Routine: 1-3 days
Set Up Days: M, W, F

Rejection criteria:
Samples containing particulate matter, and lipemic or hemolyzed specimens. Specimens that exceed stated stability, unlabeled/mislabeled/mismatched specimens, specimens submitted in leaking containers, or specimens received with insufficient volume for testing.

A summary of all tests offered by our laboratory services can be found here:


Bridgit O. Crews, PhD, DABCC
Clinical Chemistry & Toxicology

Edwin S. Monuki, MD, PhD
Department of Pathology & Laboratory Medicine

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