Test Overview

Test Usage

Simultaneously measure and monitor serum Infliximab (IFX) and antibodies to Infliximab (ATI) concentrations to clarify factors that may be contributing to a patient's loss of response and help guide treatment decisions.

Reference Range*

Serum Infliximab (IFX): <1 mcg/mL; Antibody to Infliximab (ATI): <3.1 U/mL.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details

Analytic Time

3 days

Soft Order Code




Laboratory Reference

Prometheus 3150

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Specimen Requirements

Offsite Collection Instructions

Collect specimen in a red top or SST tube. Centrifuge and aliquot serum into a plastic vial. Store and transport refrigerated or at room temperature within 5 days of collection.


Yellow Top Tube

Normal Volume

2 mL serum

Minimum Volume

0.5 mL serum

Additional Information

Test sent to Prometheus Labs. Please be advised that the fee for the Anser IFX test is $2,500.00 and the CPT code 84999 (unlisted chemistry procedure) is not covered by many insurance carriers. It is recommended that prior authorization is obtained before ordering this test. For specimens referred from a physician office, MLabs will request that Prometheus bill the 3rd party insurance carrier. The patient will be responsible for any copay or deductible balance billed by Prometheus. For additional information regarding test coverage and cost, contact the Prometheus Billing Department at 888-892-8391. If the patient is a hospital inpatient or outpatient on the date of service or client billing is specified with the test order, MLabs will bill the client $2,500.00 for this assay.

Billing Information

Fee Codes

CPT Code


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