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HelpTest Code INFXR Infliximab Quantitation with Reflex to Antibodies to Infliximab, Serum
Useful For
Trough level quantitation for evaluation of patients undergoing therapy with infliximab, infliximab-dyyb, infliximab-abda or infliximab-axxq
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 on all specimens. 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, SSpecimen 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 gel/SST are not acceptable)
Specimen Volume: 1 mL
Collection Instructions: Centrifuge within 2 hours of collection.
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
Report Available
3 to 6 daysPerforming 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 US 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 |
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 1 of the following with specimen:
-Gastroenterology and Hepatology Client Test Request (T728)
-Therapeutics Test Request (T831)
Day(s) Performed
INFX: Monday, Wednesday, Thursday
INXAB: Monday, Wednesday, Friday