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33334 - CH50 Total Complement

Test Code: 33334

TA TMA Transplant-Associated Thrombotic Microangiopathy

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Clinical and Procedure
Clinical Utility

The Complement Total, or CH50 Blood Test, assesses the overall activity of the complement system, and mainly evaluates the classic complement activation pathway. A CH50 Blood Test is often ordered to evaluate complement component deficiency and evaluate complement activity in cases of immune complex disease, glomerulonephritis (inflammation of the kidneys filters), rheumatoid arthritis and cryoglobulinemia (abnormal proteins in the blood that thicken in cold temperatures). It can also be used to evaluate a person’s response to systemic lupus erythematosus (SLE) therapy and predict disease flares. 

About CH50 Total Complement 

Complement may also be activated during reactions against incompatible blood transfusions, and during the damaging immune responses that accompany autoimmune disease.  In certain cases, after an allogenic hematopoietic cell transplantation (allo-HSCT), the complement cascade maybe activated resulting in Thrombotic microangiopathy (TA-TMA).  Thrombotic microangiopathy belongs to the family of thrombotic endothelial disorders that also includes atypical hemolytic uremic syndrome (aHUS) and thrombotic thrombocytopenic purpura (TTP). TA-TMA occurs when endothelial injury in the context of allogenic hematopoietic cell transplantation (allo-HCT) causes microangiopathic hemolytic anemia and platelet consumption, resulting in microvascular thrombosis and fibrin deposition in the microcirculation. 


This assay uses liposomes encapsulating glucose-6-phosphate dehydrogenase (G6PDH) to mimic an invading microorganism. Upon addition of sample, antibodies in the reagent combine with dinitrophenyl groups on the surface of the liposomes. The resultant complex activates complement in the sample, which lyses the liposome, releasing G6PDH to react with glucose-6-phosphate and NAD in the reagent. The change in absorbance can be measured and is proportional to the complement activity in the sample. Comparison to a calibration curve gives a value for the unknown patient sample

Turnaround Time

Same day (within 24 of hours of receipt of specimen), Monday through Saturday.

Specimen Information
Specimen Type Test Code CPT Code NY Approved Volume Assay Range Special Instructions
serum 33334 86162 Yes

0.5 ml

  • Blood should be allowed to clot 60 minutes
  • Centrifuge tube at 1000 G’s for 15 minutes ambient
  • Remove serum and transfer to a sterile screw top container immediately and store up to 14 days at -20° C or below.

Ship Monday through Friday. Friday shipments must be labeled for Saturday delivery.


Specimens are approved for testing in New York only when indicated in the Specimen Information field above. The CPT codes provided are based on Eurofins Viracor’s interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. Eurofins Viracor assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.


Jodele et al. A new paradigm: Diagnosis and management of HSCT associated thrombotic microangiopathy as multi-system endothelial injury. Blood Rev. 2015 May ; 29(3): 191–204.

Jodele et al. Complement blockade for TA-TMA: lessons learned from a large pediatric cohort treated with eculizumab. Blood 2020; 135 (13): 1049–1057. doi:

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