Use to evaluate response failure to infliximab or biosimilar therapy. Use to determine and adjust dosage or identify the need for change to another anti-TNF-α inhibitor.
Cell Culture/Quantitative Chemiluminescent Immunoassay/Semi-Quantitative Chemiluminescent Immunoassay
New York DOH Approval Status
Collect specimens before infliximab or biosimilar treatment.
Serum separator tube.
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL)
Contaminated, hemolyzed, icteric, or lipemic specimens.
After separation from cells: Ambient: 48 hours; Refrigerated: 4 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
|No||Infliximab Activity||Not Detected|
|No||Infliximab Neutralizing Antibody Titer||Not Detected|
This test measures the capacity of infliximab to neutralize TNF activity. Additionally, infliximab neutralizing antibodies (NAb) are titered, reporting the minimal serum dilution at which blocking of infliximab activity is no longer observed.
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.
*AGA recommended target trough concentration for reactive monitoring of patients with active IBD on maintenance therapy is 5 ug/mL or greater for infliximab (Feuerstein JD, et al. Gastroenterology. 2017;153:827-834). The AGA makes no recommendation regarding the use of routine, proactive therapeutic drug monitoring in adults with quiescent IBD treated with anti-TNF agents.
This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.
|Clinical Interpretation of Infliximab and Antibody Testing Results in the Context of Treatment Failure|
||Infliximab Neutralizing Antibody Titer
|Not Detected||Not Detected||Sub-therapeutic dose. A higher dosage of infliximab or shortening the dosing interval may be appropriate.|
|Not Detected||Detected||Likely immune-mediated treatment failure. A change to another anti-TNF drug may be appropriate.|
|Detected - Below Target*||N/A||Sub-therapeutic dose. A higher dosage of infliximab or shortening the dosing interval may be appropriate.|
|Detected - Above Target*||N/A||A change to another type of therapy (not targeting TNF) may be appropriate if patient is not responding.|
Laboratory Developed Test (LDT)
This test is performed pursuant to an agreement with Svar Life Sciences.
|Component Test Code*||Component Chart Name||LOINC|
|2008322||Infliximab Neutralizing Antibody Titer||86897-6|
- Anti-TNF-alpha Drug
- Human Anti-Chimeric Antibody
- Infliximab level
- Infliximab/HACA measurement
- TNFa antibody