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Test Code INFXP Infliximab Quantitation with Antibodies to Infliximab, Serum


Specimen Required


Patient Preparation:

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

For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.2 mL

Collection Instructions: Centrifuge and aliquot serum into plastic vial within 2 hours of collection.


Useful For

Trough level quantitation for evaluation of patients undergoing therapy with infliximab for proactive or reactive therapeutic drug monitoring.

Profile Information

Test ID Reporting Name Available Separately Always Performed
INFX Infliximab, S Yes, (INFXR) Yes
INXAB Infliximab Ab, S No Yes

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.

Reporting Name

Infliximab QN with Antibodies, S

Specimen Type

Serum Red

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
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, Wednesday, Thursday

INXAB: Monday, Wednesday, Friday

Report Available

3 to 6 days

Specimen Retention Time

2 weeks

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

INFX - 80230

INXAB - 82397

LOINC Code Information

Test ID Test Order Name Order LOINC Value
INFXP Infliximab QN with Antibodies, S 103791-0

 

Result ID Test Result Name Result LOINC Value
63417 Infliximab Ab, S 72623-2
63000 Infliximab, S 39803-2
36847 Interpretation 59462-2
36654 INXAB Interpretation 59462-2

Forms

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