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Overview Specimen Performance Clinical & Interpretation

Test Code:

090-81-2000

Order Name:

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

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 and report will be provided automatically.

Methodology:

INFXR, INFX: Selective Reaction Monitoring Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
INXAB: Electrochemiluminescent Bridging Immunoassay with Acid Dissociation

AliasesName:

Anti-TNF inhibitor
Auto-immune disease treatment
INFXR
INFX
INXAB
REMICADE
RENFLEXIS
Inflectra
Infliximab abda
Infliximab

Test Code:

090-81-2000

Order Name:

Infliximab Quantitation (with Reflex to Antibodies to Infliximab), Serum **

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.

Collection Specimen Or Container:

Blood/ Plain blood (Red top) 6 mL, 2 tubes

Collection Instructions:
1. Draw blood immediately before next scheduled dose (trough specimen).
2. Centrifuge within 2 hours of draw.

Specimen Testing Type:

Serum, minimum volume 1 mL x 2 tubes

Sub Mission Container:

Plastic tube

Rejection Criteria:

Gross hemolysis	Reject
Gross lipemia	OK
Gross icterus	Reject

Specimen Stabillity:

Specimen Type	Temperature	Time
Serum	Frozen (preferred)	28 days
Serum	Refrigerated, 2^oC to 8^oC	28days

Test Code:

090-81-2000

Order Name:

Infliximab Quantitation (with Reflex to Antibodies to Infliximab), Serum **

Method detail:

INFXR, INFX: Selective Reaction Monitoring Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
INXAB: Electrochemiluminescent Bridging Immunoassay with Acid Dissociation

Schedule:

N/A **Sent out to MAYO, USA

Turnaround Time:

Received specimen to reported within 21 days

Performing Location:

MAYO Laboratory
Referral Lab Services, Laboratory Department 14160-2

Test Code:

090-81-2000

Order Name:

Infliximab Quantitation (with Reflex to Antibodies to Infliximab), Serum **

Clinical Information:

Infliximab (Remicade, Renflexis, Inflectra) is a chimeric immunoglobulin (IgG1 kappa) targeting tumor necrosis factor-alpha (TNF-a), and is currently FDA-approved for the treatment of multiple inflammatory conditions. Infliximab binds to soluble TNF-a and transmembrane homotrimers.

Evaluation of infliximab concentrations may be of value for all inflammatory diseases for which it is prescribed. Primary indications for testing of infliximab include loss of response, partial response on initiation of therapy, autoimmune or hypersensitivity reactions, primary nonresponse, reintroduction after drug holiday, endoscopic/computed tomography enterography recurrence (in inflammatory bowel disease), and acute infusion reactions.

Measurement of infliximab concentrations is indicated at trough, immediately prior to the next scheduled infusion. Low trough concentrations may be correlated with loss of response to infliximab. Assessment of antibodies to infliximab is suggested when infliximab quantitation at trough is 5.0 mcg/mL or less.

Reference Value:

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 > or =50 U/mL

Interpretation:

Low trough concentrations may be correlated with loss of response to infliximab. For infliximab trough concentrations 5.0 mcg/mL or less, testing for antibodies to infliximab (ATI) is suggested.

For infliximab trough concentrations above 5.0 mcg/mL, the presence of ATI is unlikely; patients experiencing loss of response to infliximab may benefit from an increased dose or a shorter infusion interval.

Results above 35 mcg/mL are suggestive of a blood draw at a time-point in treatment other than trough.

Clinical Reference: