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Infliximab Quantitation with Reflex to Antibodies to Infliximab, Serum

Additional Codes

Primary ID

Epic Code

Mayo Test ID

INFXQ

LAB3300

INFXR

 

Useful For

Trough level quantitation for evaluation of patients with loss of response to infliximab and infliximab-dyyb

Profile Information

Test ID Reporting Name Available Separately Always Performed
INFX Infliximab, S No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
INXAB Infliximab Ab, S No No

Testing Algorithm

Infliximab will be performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on all samples. When Infliximab results are below 5.1 mcg/mL, testing for antibodies to infliximab will be performed at an additional charge.

Reporting Name

Infliximab QN with Reflex to Ab, S

Specimen Type

Serum Red


Specimen Required


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

Container/Tube: Red top

Specimen Volume: 1 mL

Collection Instructions:

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

2. Centrifuge within 2 hours of draw.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

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

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus 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

Analytic Time

3 days

Specimen Retention Time

2 weeks

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

80230

82397-(if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
INFXR Infliximab QN with Reflex to Ab, S 39803-2

 

Result ID Test Result Name Result LOINC Value
63000 Infliximab, S 39803-2
36847 Interpretation 59462-2

NY State Approved

Yes

Method Name

INFXR, INFX: Selective Reaction Monitoring Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

INXAB: Electrochemiluminescent Bridging Immunoassay

Forms

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

Day(s) and Time(s) Performed

INFX: Monday, Wednesday, Thursday; 4 p.m.

INXAB: Monday, Wednesday, Friday; 8 a.m.