Table 3. Summary of useful antibody-detecting assays.

Assay	Advantages	Disadvantages
ELISA	Simple, with acceptable sensitivity; reagents readily available	Anti-drug antibody measurements may be confounded by the presence of rheumatoid factor and anti-hinge antibodies, and high levels of circulating drug (the presence of the drug may lead to false negative results as the current assays measure unbound antibodies, not those bound in an immune complex)
RIA	Good sensitivity; ready-to-use reagents; limited costs	May be influenced by high levels of circulating drug; occupational exposure to radioactive materials
ECL assay	Highly sensitive: minimal influence of sample matrix	Requires an ECL instrument; reagents may be expensive
Gyros	Excellent sensitivity; reduced drug interference; low-volume samples; minimal use of critical reagents; time saving	High costs of reagents and consumables; the short incubation time for a neutralization and bridging reaction may not be sufficient if sample contains low affinity antibodies

Abbreviations: ELISA, enzyme linked immunosorbent assay; RIA, radioimmuno assay; ECL electrochemiluminescence.