Evaluate response failure to infliximab therapy. Determine and adjust dosage or identify the need for change to another anti-TNF-α inhibitor.
- Patient Preparation
- Collect specimens before infliximab treatment.
- Serum separator tube.
- Specimen Preparation
- Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.3 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- 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 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.
|AND Infliximab 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 greater||Not Detected||A change to another type of therapy (not targeting TNF-α) may be appropriate.|
|0.65 ug/mL or greater||1:20 or greater||Repeat testing is suggested to rule out decreasing infliximab activity and/or increasing infliximab neutralizing antibodies.|
|Component Test Code*||Component Chart Name||LOINC|
|2008322||Infliximab Neutralizing Antibody Titer||72623-2|
- Anti-TNF-alpha Drug
- Human Anti-Chimeric Antibody
- Infliximab level
- Infliximab/HACA measurement
- TNFa antibody