Specimen Collection Manual and Test Catalog

2 mL serum, minimum 1 mL.

The blood should be drawn just before the next infusion of infliximab to measure the trough drug level.

For up to 48 hours before blood draw, do not take multivitamins or dietary supplements containing biotin or vitamin B7

Refrigerated.

Room temperature: 48 hours. Refrigerated: 7 days. Frozen -20°C: 14 days. Frozen -70°C: 60 days.

Serum Separator Tube (SST). Gross hemolysis. Grossly icteric.

Infliximab Level, Infliximab AB

Remicade® antibody,Anti-TNF blocker,TNF inhibitor antibody,Anti-TNF inhibitor antibody,Anti-Remicade® antibody, Quest GMC Limited Access Code 38299, INFLIXIMAB LEVEL AND ANTI-DRUG ANTIBODY FOR IBD, INFLIX

The American Gastroenterological Association recommends optimal infliximab trough concentration of 5 mcg/mL or greater in patients with active IBD. Data from separate clinical studies suggest an optimal infliximab trough concentration of greater than 3.8 or 6-10 mcg/mL. Sub- therapeutic infliximab 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 infliximab clearance. Accelerated infliximab clearance may be explained by the presence of infliximab 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 infliximab level is sub-therapeutic but total infliximab anti-drug antibody is not detected: Patients with a sub-therapeutic infliximab trough level, but no anti-drug antibody, may benefit from an increased infliximab dose. If infliximab level is sub-therapeutic and total infliximab anti-drug antibody is detected: Detectable serum infliximab anti-drug antibody may cause accelerated infliximab 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 infliximab dose. If infliximab level is therapeutic and total infliximab anti-drug antibody is not detected: In patients who do not respond or who lose their clinical response, mucosal 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 infliximab level is therapeutic and total infliximab 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 infliximab clearance. Anti-drug antibody may disappear over time or increase, and, if increased, may cause sub-therapeutic infliximab levels and a loss of response in the future. Patients with a loss of infliximab response despite therapeutic trough levels may benefit from a switch to a different class of therapy.