Rituximab and Anti-Rituximab Antibody

Rituximab Drug Concentration and Anti-Rituximab Antibody Levels

CPT: 80299; 82397
Updated on 2/11/2019
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Test Details


  • Anti-CD20
  • Biologics
  • Biopharmaceutical
  • Rituxan®


Therapeutic monitoring of rituximab and antidrug antibody development for individuals with non-Hodgkin's lymphoma (NHL), chronic lymphocytic leukemia (CLL), and rheumatoid arthritis. This test provides rituximab drug concentration as well as the level of anti-rituximab antibodies.


Failure of rituximab therapy may not always be due to the presence of anti-rituximab antibodies. Conversely, the absence of anti-rituximab antibodies does not guarantee positive response to treatment.

This test was developed, and its performance characteristics determined, by LabCorp. It has not been cleared or approved by the US Food and Drug Administration (FDA).


Electrochemiluminescence immunoassay (ECLIA); chemiluminescence immunoassay (CLIA)

Specimen Requirements


Serum (preferred) or heparin plasma


3 mL

Minimum Volume

1 mL (Note: This volume does not allow for repeat testing.)


Gel-barrier tube, red-top tube, or green-top (heparin) tube


Serum or plasma must be separated from cells within 45 minutes of venipuncture. Submit serum or plasma in a plastic transport tube. To avoid delays in turnaround time when requesting multiple test on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions


Stability Requirements



Room temperature

7 days


14 days


14 days

Freeze/thaw cycles

Stable x6

Causes for Rejection

Gross hemolysis; gross lipemia; icteric specimen

Clinical Information

Special Instructions

This test includes Serial Monitoring.


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
504355 RTA Conc+RTA Ab 504356 Rituximab Drug Concentration ug/mL 82467-2
504355 RTA Conc+RTA Ab 504357 Anti-Rituximab Antibody Level ng/mL 82466-4
Reflex Table for Anti-Rituximab Antibody Level
Order Code Order Name Result Code Result Name UofM Result LOINC
Reflex 1 000000 Serial Monitoring 000000 Serial Monitoring N/A

For Providers

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