Adalimumab Level and Anti-drug Antibody for Rheumatic Diseases

Test Code
ADARHEUM


Quest Code
36297


CPT Codes
83520, 80145<br /> **This test is not available for New York patient testing**

Preferred Specimen
2 mL serum collected in a red-top tube (no gel)


Patient Preparation
No biotin supplements 48 hours prior to blood draw.
The blood should be drawn just before the next infusion of adalimumab to measure the trough drug level.

Minimum Volume
1 mL


Transport Temperature
Refrigerated (cold packs)


Specimen Stability
Room temperature: 48 hours
Refrigerated: 7 days
Frozen -20°C: 14 days
Frozen -70°C: 42 days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Serum Separator Tube (SST) • Gross hemolysis


Methodology
Enzyme Linked Immunosorbent Assay (ELISA)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Tuesday Morning
Report available: 3 Days


Reference Range
See Laboratory Report


Clinical Significance
Several studies suggest a target adalimumab trough concentration of 5-12 mcg/mL. Sub-therapeutic adalimumab levels may be due to a patient not yet achieving a steady state trough level early in therapy, inadequate dosing, a dosing interval that is too long, or accelerated adalimumab clearance. Accelerated adalimumab clearance may be explained by the presence of adalimumab anti-drug antibody or rheumatoid factor in the patient's serum, or may be caused by other diseases that indirectly lead to immunoglobulin loss (i.e. kidney disease, protein-losing gastroenteropathy).
If adalimumab level is sub-therapeutic but total adalimumab anti-drug antibody is not detected: Patients with a sub-therapeutic adalimumab trough level, but no anti-drug antibody, may benefit from an increased adalimumab dose.
If adalimumab level is sub-therapeutic and total adalimumab anti-drug antibody is detected: Detectable serum adalimumab anti-drug antibody may cause accelerated adalimumab clearance leading to reduced trough levels and a compromised clinical response. Such patients are more likely to benefit from a switch in biologic therapy than from an increase in adalimumab dose.
If adalimumab level is therapeutic and total adalimumab anti-drug antibody is not detected: Patients who do not respond or who lose their clinical response, inflammation is likely to be driven by a process that is not TNF alpha dependent. A switch to a different class of therapy should be considered.
If adalimumab level is therapeutic and total adalimumab anti-drug antibody is detected: If the patient is responding clinically, the detected anti-drug antibody may not be clinically significant because the detected anti-drug antibody may not be functional or the level is inadequate to accelerate adalimumab clearance. Anti-drug antibody may disappear over time or increase, and, if increased, may cause sub-therapeutic adalimumab levels and a loss of response in the future. Patients with a loss of adalimumab response despite therapeutic trough levels may benefit from a switch to a different class of therapy. Addition of methotrexate to the treatment regimen may suppress development of ADA.


Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.