Adalimumab Antibody Levels

Blood Sciences Test

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**** Please note: the positivity threshold for Adalimumab total anti-drug antibodies has changed  to >/= 6 AU/mL****

Based on the 99th centile concentration of sera from 498 anti-TNF
naïve healthy adults (1)

Specimen

Serum

Units

AU/mL (arbitrary units per mL)

Test Usage

Interpretation of Adalimumab antibody levels

General points

This assay measures TOTAL Adalimumab Antibody concentration.

Total Antibody concentration >/= 6 AU/mL is positive. The distribution for 600 positive results is as follows:

Centile range	Total Adalimumab antibodies (AU/mL)
0 – 5th	6 – 11
6th – 25th	12 – 21
26th – 50th	22 – 57
51st – 75th	58 – 199
>76th	>200

The top of the measuring range is 200 AU/mL. This corresponds to the 76th Centile

For further interpretation please see: Anti TNF monitoring guidance

Biotin Interference

The ELISA immunoassay method used for adalimumab 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 >477 nmol/L.

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

 If you have any further enquiries please contact the Duty Biochemist by email:  rduh.biochem@nhs.net

References

1. Nice R, Chanchlani N, Green H, Bewshea C, Ahmad T, Goodhand J R, McDonal TJ, Perry Mandy H, Kennedy, Nicholas A. Validating the positivity thresholds of drug-tolerant
   anti-infliximab and anti-adalimumab antibody assays. AP&T 2020 Sept 02, DOI: 10.1111/apt.16135
2. 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:Adalimumab and Anti-Adalimumab Antibodies – further information

Specimen Labelling Procedure

Specimen Labelling Procedure