The two tier testing system endorsed by the Centers for Disease Control and Prevention (CDC) has a high specificity (99%) and yields few false positives. But the tests have a uniformly miserable sensitivity (56%)—they miss 88 of every 200 patients with Lyme disease (table). By comparison, AIDS tests have a sensitivity of 99.5%—they miss only one of every 200 AIDS cases. In simple terms, the chance of a patient with Lyme disease being diagnosed using the commercial tests approved by the Food and Drug Administration and sanctioned by the CDC is about getting heads or tails when tossing a coin, and the poor test performance assures that many patients with Lyme disease will go undiagnosed.
Sensitivity and specificity of commercial two tier testing for Lyme disease
| Study | Sensitivity | Specificity |
|---|---|---|
| Schmitz et al. Eur J Clin Microbiol Infect Dis 1993;12:419-24 | 66% | 100% |
| Engstrom et al. J Clin Microbiol 1995;33:419-27 | 55% | 96% |
| Ledue et al. J Clin Microbiol 1996;34:2343-50 | 50% | 100% |
| Trevejo et al. J Infect Dis 1999;179:931-8 | 29% | 100% |
| Nowakowski et al. Clin Infect Dis 2001;33:2023-7 | 66% | 99% |
| Bacon et al. J Infect Dis 2003;187:1187-99 | 68% | 99% |
| Mean of all studies | 56% | 99% |
Until we scrap the worthless commercial tests for Lyme disease and find a better way to make the diagnosis of this protean illness, the “Lyme wars” will continue unabated.1
Competing interests: RBS serves on the advisory panel for QMedRx.
References
- 1.Tonks A. Lyme wars. BMJ 2007;335:910-2. (3 November.) [DOI] [PMC free article] [PubMed] [Google Scholar]