Evaluation of standard and modified two-tiered testing algorithms using well-characterized early Lyme disease samples

Current laboratory testing for Lyme disease (LD) relies on serology. We evaluated the performance of standard two-tiered testing (STTT) and modified two-tiered testing (MTTT) algorithms using samples obtained from well-characterized patients with early LD in the U.S. East Coast and Upper Midwest. Participants with signs and symptoms of early LD (cases) and controls were enrolled by Lyme Disease Biobank. We compared the performance of four FDA-cleared STTT or MTTT algorithms using serum samples from 251 participants (107 cases, 69 with a convalescent draw; 144 endemic controls). At the initial blood draw, algorithm sensitivity ranged from 22% to 36%, with specificity ranging from 98% to 100%. MTTT algorithms showed higher sensitivity compared with STTT algorithms (P ≤ 0.05). One STTT algorithm was less sensitive than the other (P = 0.035), and there was no significant difference in sensitivity between MTTT algorithms. There was also discordance between algorithms; only 22 of the 45 samples classified as laboratory confirmed by Lyme Disease Biobank testing were positive using all algorithms evaluated. Likelihood of positive two-tiered serology among cases with a suspected erythema migrans (EM) skin lesion increased with longer lesion duration and/or when presenting with >1 constitutional symptom. Participants with suspected EM without constitutional symptoms were unlikely to test positive by any algorithm evaluated. Testing convalescent samples did not improve LD detection, and seroconversion was rare. While MTTT confirmed more early LD cases than STTT, all two-tiered algorithms evaluated were insensitive in this population. Novel diagnostics that improve laboratory confirmation for early LD are urgently needed.

This study confirms that two-tiered serologic testing algorithms are insensitive in early Lyme disease, particularly within the first 2 weeks after symptom onset or when erythema migrans is not accompanied by constitutional symptoms. It also demonstrates that seroconversion is rare after antibiotic treatment. These results highlight the need for novel diagnostics for early Lyme disease that do not rely on serologic testing.