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Test Code C5B9 SC5b-9 Level Terminal Complement Complex, Plasma


Ordering Guidance


If testing to evaluate C5b-9 in the context of atypical hemolytic uremic syndrome is desired, see AHUSD / Atypical Hemolytic Uremic Syndrome Complement Panel, Serum and Plasma.



Specimen Required


Patient Preparation:

1. Fasting preferred but not required.

2.  Do not collect specimens for at least 48 hours following plasma exchange.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Lavender top (K2 EDTA)

Acceptable: Lavender top (K3 EDTA), light-blue top (sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions:

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

2. Centrifuge between 1000 and 2000 x g for 10 minutes at 4° C and aliquot plasma into a plastic vial.

3. Within 30 minutes of centrifugation, freeze specimen. Sample must be placed on dry ice if not frozen immediately.

NOTE: If a refrigerated centrifuge is not available, it is acceptable to use a room temperature centrifuge, provided the sample is kept on ice before centrifugation, and immediately afterward, the plasma is aliquoted and frozen.


Useful For

Detecting increased complement activation

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

SC5b-9 Complement, P

Specimen Type

Plasma EDTA

Specimen Minimum Volume

0.75 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma EDTA Frozen 14 days

Reference Values

≤250 ng/mL

Interpretation

Elevated concentrations of soluble C5b-9 suggest recent or ongoing activation of the complement system, while normal and low concentrations suggest that the complement system has not been excessively activated.

 

A panel of complement tests may be clinically indicated to further identify the extent of the complement activation, along with the information of which pathway is most dysregulated.

Clinical Reference

1. Qi J, Wang J, Chen J, Su J, et al. Plasma levels of complement activation fragments C3b and sC5b-9 significantly increased in patients with thrombotic microangiopathy after allogeneic stem cell transplantation. Ann Hematol. 2017;96(11):1849-1855

2. Horvath O, Kallay K, Csuka D, et al. Early increase in complement terminal pathway activation marker sC5b-9 Is predictive for the development of thrombotic microangiopathy after stem cell transplantation. Biol Blood Marrow Transplant. 2018;24(5):989-996

3. Mezo B, Horvath O, Sinkovits G, Veszeli N, Krivan G, Prohaszka Z. Validation of early increase in complement activation marker sC5b-9 as a predictive biomarker for the development of thrombotic microangiopathy after stem cell transplantation. Front Med (Lausanne). 2020;7:569291

4. Jodele S, Dandoy CE, Lane A, et al. Complement blockade for TA-TMA: lessons learned from a large pediatric cohort treated with eculizumab. Blood. 2020;135(13):1049-1057

5. Young JA, Pallas CR, Knovich MA. Transplant-associated thrombotic microangiopathy: theoretical considerations and a practical approach to an unrefined diagnosis. Bone Marrow Transplant. 2021;56(8):1805-1817

Day(s) Performed

Varies

Report Available

3 to 5 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86160

LOINC Code Information

Test ID Test Order Name Order LOINC Value
C5B9 SC5b-9 Complement, P 93244-2

 

Result ID Test Result Name Result LOINC Value
616921 SC5b-9 Complement, P 93244-2