A-264 Comparison of the ZEUS Scientific Lyme Assays to the DiaSorin Liaison Lyme Assays Using a Modified Two-Tiered Testing Algorithm for Lyme Disease

Abstract

Abstract Background Lyme borreliosis is the most common vector-borne disease in the United States. Modified two-tiered testing (MTTT) strategies have recently been developed that use enzyme immunoassays as the second tier test in place of an immunoblot. We directly compared two sets of MTTT assays with samples obtained from the northeastern United States, a Lyme disease endemic area. Methods Remnant specimens from 120 patients initially tested by the ZEUS Scientific Lyme ELISAs in accordance with an MTTT algorithm were analyzed with the DiaSorin Lyme chemiluminescent immunoassays. The ZEUS assays were performed on a DYNEX DS2 and the DiaSorin assays were performed on the DiaSorin Liaison XL. Analytical concordance was evaluated. Results Of the 25 samples that were negative by the ZEUS VlsE1/pepC10 IgG/IgM assay, 100% (25/25) were negative by the DiaSorin Lyme Total Antibody Plus assay. Of the 95 samples that were presumptive positive or equivocal by the ZEUS IgG/IgM assay, 64% (61/95) were presumptive positive or equivocal and 36% (34/95) were negative by the DiaSorin Lyme Total assay. Samples that tested presumptive positive or equivocal on the ZEUS IgG/IgM or DiaSorin Lyme Total were evaluated by the respective IgG and IgM assays. Positive IgG results and negative IgM results demonstrated >90% agreement between the ZEUS and DiaSorin assays (Table 1). Overall clinical interpretation was concordant between the ZEUS and DiaSorin MTTTs in 57% (54/95) of patients who tested presumptive positive or equivocal on the ZEUS IgG/IgM. Twenty-four samples that tested positive for IgM by the ZEUS assay tested negative for DiaSorin Lyme Total or IgM assays. Conclusion Comparison of the DiaSorin Lyme assays to the ZEUS Lyme assays using an MTTT algorithm suggests that the DiaSorin assays would result in fewer positive screening tests, decreasing unnecessary secondary testing, and may result in fewer patients treated with antibiotics.