The iLite® Diluent B may be used in both the anti-TNF-alpha drug concentration assay and in the anti-TNF-alpha NAb assay. It should be used for the first dilution step of test samples (Diluent A / Diluent C is used for the consecutive steps) and for the dilution of iLite® TNF-alpha Assay Ready Cells. Tumor necrosis factor alpha (TNF-alpha) promotes inflammatory responses, which, in turn, contribute to the clinical problems associated with many inflammatory disorders, including rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, psoriasis and refractory asthma. These diseases are sometimes treated with TNF-alpha inhibitors, including infliximab, adalimumab, etanercept, certolizumab pegol or golimumab. Prolonged therapies with these TNF-alpha inhibitors may lead to development of neutralizing antibodies (NAbs), which may counteract the TNF-alpha antagonist activity of the drugs.