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Test ID INFXP Infliximab Quantitation with Antibodies to Infliximab, Serum


Specimen Required


Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.2 mL Serum

Collection Instructions:

1. Draw blood immediately before next scheduled dose (trough specimen).

2. Within 2 hours of collection, centrifuge and aliquot serum into plastic vial.


Secondary ID

620151

Useful For

Evaluating patients for loss of response, partial response on initiation of therapy, autoimmune or hypersensitivity reactions, primary nonresponse, reintroduction after drug holiday, endoscopic/computed tomography enterography recurrence (in inflammatory bowel disease), acute infusion reactions and proactive monitoring

 

These assays do not differentiate between the originator and biosimilar products.

Testing Algorithm

When this test is ordered, infliximab quantitation and testing for antibodies to infliximab will always be performed.

 

For more information see Ulcerative Colitis and Crohn Disease Therapeutic Drug Monitoring Algorithm.

Specimen Type

Serum Red

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 28 days
  Frozen  28 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus Reject
Heat-Treated Reject

Reference Values

INFLIXIMAB QUANTITATION:

Limit of quantitation is 1.0 mcg/mL. Therapeutic ranges are disease specific.

 

Pediatric reference ranges are not established.

 

INFLIXIMAB ANTIBODIES

Absence of antibodies to infliximab (ATI) is defined as <50 U/mL

Presence of ATI is reported as positive when concentrations are ≥50 U/mL

Day(s) Performed

INFX: Monday through Friday

INXAB: Monday, Wednesday, Friday

Report Available

3 to 6 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

INFX-80230

INXA -82397

Forms

If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.