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HelpTest Code FIAIA Infliximab Quantitation with Reflex to Antibodies to Infliximab, Serum
Reporting Name
Infliximab QN with Reflex to Ab, SUseful For
Trough level quantitation for evaluation of patients with loss of response to infliximab and infliximab-dyyb
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedSpecimen Required
Patient Preparation:
1. Draw blood immediately before next scheduled dose (trough specimen).
2. 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.
Container/Tube: Red top (serum ger/SST are not acceptable)
Specimen Volume: 1 mL
Collection Instructions: Centrifuge within 2 hours of collection.
Specimen Minimum Volume
0.5 mL
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.
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Frozen (preferred) | 28 days | |
| Refrigerated | 28 days |
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
INFX: Monday, Wednesday, Thursday; 4 p.m.
INXAB: Monday, Wednesday, Friday; 8 a.m.
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 |
Clinical Reference
1. Colombel JF, Sandborn WJ, Reinisch W, et al: Infliximab, azathioprine, or combination therapy for Crohn's disease. N Engl J Med. 2010;362:1383-1395
2. Jurgens M, Mahachie John JM, Cleynen I, et al: Levels of C-reactive protein are associated with response to infliximab therapy in patients with Crohn's disease. Clin Gastroenterol Hepatol. 2011;9:421-427.e1
3. Ordas I, Mould DR, Feagan BG, Sandborn WJ: Anti-TNF monoclonal antibodies in inflammatory bowel disease: pharmacokinetics-based dosing paradigms. Clin Pharmacol Ther. 2012;91:635-646
4. Afif W, Loftus EV Jr, Faubion WA, et al: Clinical utility of measuring infliximab and human anti-chimeric antibody concentrations in patients with inflammatory bowel disease. Am J Gastroenterol. 2010;105:1133-1139
5. Imaeda H, Bamba S, Takahashi K, et al: Relationship between serum infliximab trough levels and endoscopic activities in patients with Crohn's disease under scheduled maintenance treatment. J Gastroenterol. 2014 Apr;49(4):674-682
6. Steenholdt C, Bendtzen K, Brynskov J, et al: Cut-off levels and diagnostic accuracy of infliximab trough levels and anti-infliximab antibodies in Crohn's disease. Scand J Gastroenterol. 2011;46:310-318
7. Silva-Ferreira F, Afonso J, Pinto-Lopes P, Magro F: A systematic review on Infliximab and Adalimumab drug monitoring: Levels, clinical outcomes and assays. Inflamm Bowel Dis. 2016 Sep;22(9):2289-2301
Method Description
Infliximab Quantitation:
This test is performed using liquid-chromatography and tandem mass spectrometry. Preanalytical sample preparation includes a trypsin digestion; 2 unique clonotypic peptides from the heavy and light chains of the infliximab chimeric structure (IgG1 kappa) are monitored.(Willrich MA, Murray DL, Barnidge DR, et al: Quantitation of infliximab using clonotypic peptides and selective reaction monitoring by LC-MS/MS. Int Immunopharmacol. 2015;28:513-520)
Infliximab Antibodies:
This lab developed immunoassay is designed to measure antibodies-to-infliximab (ATI) in human serum by means of electrochemiluminescence (ECL) on the MesoScale Discovery (MSD) platform. The assay uses a "bridging" format in which the ATI forms a link between biotin labeled infliximab and SULFO-Tag labeled infliximab. The biotin binds to a streptavidin (SA) coated surface and the SULFO-Tag creates a signal in the presence of a conjugate following application of an electric current. During sample preparation, serum is mixed with acetic acid to break the infliximab/ATI complex. Biotinylated and SULFO-Tagged infliximab are then added and bind with ATI that is present in the sample. After the incubation with the labeled drug, the calibrators, controls, and samples are added to a SA plate that has been blocked with a solution of bovine serum albumin (BSA). The biotinylated infliximab then binds to the SA plate. After an incubation period, the SA plate is washed and MSD read buffer is added. Immediately after the addition of read buffer, the plate is analyzed. The read buffer provides an appropriate chemical environment for ECL when a voltage is applied to the electrodes on the plate. This voltage causes bound SULFO-Tagged infliximab to emit measureable light. The intensity of emitted light is measured and correlated to a set of standards with known concentrations of ATI by means of a 4-point logistics curve fitting method.(Willrich M, Balsanek J, Ladwig P, et al: A-374 Antibodies-to-Infliximab: Assay Development and Correlation with Infliximab Concentrations in Serum Samples of Treated Patients. AACC Annual Meeting; Chicago: AACC Press; 2014 pS110; Balsanek J, Willrich MAV, Murray DL, Snyder M: Sa1268 Clinical Development of an Electrochemiluminescent Immunoassay to Measure Antibodies-to-Infliximab. Gastroenterology. 2014;146[5]:S-248)
Analytic Time
3 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | Reject |
Method Name
INFXR, INFX: Selective Reaction Monitoring Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
INXAB: Electrochemiluminescent Bridging Immunoassay with Acid Dissociation
Forms
If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Client Test Request (T728) with the specimen.
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 |