Infliximab Activity and Neutralizing
Label Mnemonic: IFX NAB
Epic Lab Code: LAB8272
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Serum
Specimen Instructions:
Collect specimens before infliximab treatment.
Collection Medium:
Red top tube 5 mL (Clot Activator)
Minimum:
Preferred Minimum: 1 mL serum
Absolute Minimum: 0.5 mL serum
Rejection Criteria:
Contaminated, hemolyzed, icteric, or lipemic specimens.
Turn Around Time:
2-3 days upon receipt at reference laboratory
Reference Range:
Infliximab Activity - Not Detected
Infliximab Neutralizing Antibody Titer - Not Detected
Interpretive Data:
This test measures the capacity of infliximab to neutralize TNF- activity. Additionally, infliximab neutralizing antibodies (NAb) are titered (reporting the highest dilution of patient sera in which NAb activity is detected). This test is used to evaluate secondary response failures to infliximab therapy. Secondary response failure is defined as loss of clinical response after initial improvement of clinical signs and symptoms. Therapeutic decision should rest on both the clinical response and the knowledge of the fate of the drug including the emergence of immunogenicity in individual patients. Circulating infliximab levels have been shown to vary considerably between patients. These differences relate to route and frequency of administration and patient-related features such as age, gender, weight, drug metabolism, and concomitant medications such as methotrexate and other immunosuppressants. IF Infliximab AND Infliximab THEN.... Activity is.... Neutralizing Ab. Titer is.... Not Detected Not Detected A higher dosage of infliximab or shortening the dosing interval may be appropriate. Not Detected 1:20 or greater A change to another anti- ​TNF-​α drug may be appropriate. 0.65 ug/mL or Not Detected A change to another type of greater therapy (not targeting TNF-​α) may be appropriate. 0.65 ug/mL or 1:20 or greater Repeat testing is suggested to greater rule out decreasing infliximab activity and/or increasing infliximab neutralizing antibodies.
Methodology:
Cell Culture/Quantitative Chemiluminescent Immunoassay/Semi- Quantitative Chemiluminescent Immunoassay
CPT Code:
86352 x2