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Test ID BLOD1339 Infliximab Quantitation with Reflex to Antibodies to Infliximab, Serum

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


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
Serum Red Frozen (preferred) 28 days
  Refrigerated  28 days

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross OK

Icterus

Mild OK; Gross reject

Other

Plasma, whole blood, SST tubes

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) and Time(s) Performed

INFXR: Monday, Wednesday, Thursday, 4 p.m.

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

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

80299

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 Test Request Form (T728) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/gastroenterology-and-hepatology-test-request.pdf)