Single-step immunoblot tests with recombinant protein antigens for detecting IgG and IgM antibodies in Lyme disease

Serodiagnosis is important in Lyme disease (LD). Until recently, this commonly required two separate tests termed the standard two-tier tests (STTTs). One-step immunoblot (IB) tests utilizing recombinant protein targets from multiple Borrelia species and strains that may simplify the serodiagnosis of LD are now described. Specificity of the IB tests was established with 425 sera from healthy persons and 387 sera from persons with potentially confounding infections and medical conditions. Test sensitivities were determined with (i) 90 sera from patients with different stages of LD from the US Centers for Disease Control and Prevention (CDC), and (ii) 290 prospectively banked sera from patients with acute-stage LD from the Bay Area Lyme Foundation's Lyme Disease Biobank (BALDB). The IgG IB test was more sensitive than a US Food and Drug Administration (FDA)-cleared STTT for detecting IgG antibodies in stage 1 LD sera from the CDC's test panel (P = 0.002). The diagnostic performance of the IgG and IgM IB tests demonstrated significantly greater overall sensitivity than the comparable FDA-cleared STTTs for detecting IgG and/or IgM antibodies in the 290 BALDB sera (P = 0.00004). The IgG IB test was also more sensitive than the IgG STTT for detecting IgG antibodies in the 290 BALDB sera (P < 0.000001). The IgG and IgM IB tests were additionally more sensitive than IgG and IgM STTTs for detecting IgG and/or IgM antibodies in BALDB sera from 189 patients with erythema migrans (P = 0.03). The IB tests described here form the basis for one-step IgG and IgM IB tests, termed iDart IgG and IgM IB tests, cleared by the FDA for LD diagnosis.IMPORTANCEThe immunoblot (IB) tests described here are one-step tests that separately detect IgG and IgM antibodies for the serological diagnosis of Lyme disease in the United States. The IB tests are more sensitive than a common standard two-tier test for detecting antibodies in early-stage Lyme disease. This can assist in the diagnosis of Lyme disease when antibodies have not yet reached their maximum concentration in patient sera.