Infliximab Antibody Levels

Blood Sciences Test

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Specimen

Serum

Special instructions

None

Units

AU/mL (arbitrary units per mL)

Test Usage

Interpretation of Infliximab antibody levels

General points

This assay measures TOTAL Infliximab Antibody concentration.

Total Antibody concentration >/= 10 AU/mL is positive. The distribution for 3760 positive results is as follows: 

Centile range	Total Infliximab antibodies (AU/mL)
0 – 5th	10 – 11
6th – 25th	12 – 18
26th – 50th	19 – 40
51st – 75th	41 -115
76th – 95th	116 – 400
>95th	>400

The top of the measuring range is 400 AU/mL. This corresponds to the 95^th Centile

For further interpretation please see: Anti TNF monitoring guidance

Biotin Interference

The ELISA immunoassay method used for infliximab total anti-drug antibody measurement at Exeter Blood Sciences laboratory uses a streptavidin-biotin system in its design. If patients are taking large doses of Biotin (Vitamin B7), there is potential for interference in this assay with a possibility of lowered results when biotin concentration >318 nmol/L.

For further information on biotin interference please see: https://www.exeterlaboratory.com/biotin-alert-potential-assay-interference/

References

• Perry M, Bewshea C, Brown R, So K, Ahmad T, McDonald T. Infliximab and adalimumab are stable in whole blood clotted samples for seven days at room temperature. .Ann Clin Biochem.2015 Mar 16. pii: 0004563215580001. [Epub ahead of print]

AVAILABILITY

Local test

TURNAROUND TIME

10 days

Can be added on to an existing request

REFERRALS

We welcome referrals for Anti TNF monitoring. If you are a new requestor please complete the following form: New requestor form

We now also have the option to use NPEx for referral requesting.

Further information about sample requirements for this test can be found here: Infliximab and Anti-Infliximab Antibodies – further information

Specimen Labelling Procedure

 

Specimen Labelling Procedure