Lyme Disease Confirmatory Western Blot Is Redundant for Screen Negative Samples in Low Endemic Areas, British Columbia, Canada.

is the causative agent of Lyme disease (LD). Possible early symptoms include flu-like symptoms and erythema migrans and later, the risk of disruption of the nervous system, joints, and heart. A two-tiered testing method is employed for serological diagnostics. The Public Health Agency of Canada guidelines recommend that samples tested negative on first-tiered test need not be confirmed by second-tiered test. Due to the challenging nature of diagnosis leading to misconceptions among physicians about false negatives, confirmatory testing is requested despite the initial negative result. Hundred screen-negative Lyme patient samples from 2007 to 2016 were tested by Western blot (WB) second-tiered confirmatory test upon physician's request in British Columbia to study the first-tiered screening test sufficiency. Those negative for first-tiered enzyme-linked immunosorbent assay were also negative by WB. Results demonstrate that confirmatory testing is not necessary on screen-negative samples. Hence, first-tiered test is sufficient to rule out LD.