Infliximab Activity and Neutralizing Antibody
2008320
Ordering Recommendation
Aid in evaluation of response failure to infliximab therapy.
Mnemonic
IFX NAB
Methodology
Cell Culture/ Cell function assay involving cell stimulation /Quantitative Chemiluminescent Immunoassay/ Semi-Quantitative Chemiluminescent Immunoassay
Performed
Mon, Wed, Thu, Sat
Reported
2-3 days  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
Collect specimens before infliximab treatment.  
Collect
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
Refrigerated.  
Unacceptable Conditions
Contaminated, hemolyzed, icteric, or lipemic specimens.  
Remarks
  
Stability
After separation from cells: Ambient: 48 hours; Refrigerated: 4 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)  
Reference Interval
 
 
Available
Separately
Components Reference Interval
No Infliximab Activity Not Detected
No 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.

See Compliance Statement B: www.aruplab.com/CS
 
IF Infliximab
Activity is....
AND Infliximab Neutralizing
Ab. Titer is....
THEN....
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.
Note
This test is performed pursuant to an agreement with Biomonitor.
CPT Code(s)
86352x2
Components
Component Test Code*Component Chart Name
2008321Infliximab Activity
2008322Infliximab Neutralizing Antibody Titer
2008323EER Infliximab
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Anti-INF-alpha Drug
  • Human Anti-Chimeric Antibody
  • IFD
  • Infliximab/HACA measurement
  • Remicade
  • TNFa antibody