Role of serology in the diagnosis of Lyme disease

Numerous concerns regarding the potential for misdiagnosis of Lyme disease using commercial assays have been voiced by the US Food and Drug Administra tion (FDA). We attempted to clarify the clinical value of serologic testing for Lyme disease using the results of commonly marketed assays for detecti ng antibody to Borrelia burgdorferi, the organism that causes Lyme disease, We reviewed published studies on B burgdorferi test performance published through 1998, package insert labeling from FDA-cleared test kits for B burg dorferi, and Lyme Disease Survey Set LY-A from the College of American Path ologists. We assessed the sensitivity and specificity of commercial serolog ic tests (enzyme-linked immunosorbent assay [ELISA], immunofluorescence ant ibody [IFA], and immunodot) for diagnosis of Lyme disease. To reduce this r isk of misdiagnosis, it is important that clinicians understand the perform ance characteristics and limitations of these tests. These tests, in common use in clinical or commercial laboratories, should be used only to support a clinical diagnosis of Lyme disease, not as the primary basis for making diagnostic or treatment decisions. Serologic testing is not useful early in the course of Lyme disease because of the low sensitivity of tests in earl y disease. Serologic testing may be more useful in later disease, at which time sensitivity and specificity of the test are improved. Positive or equi vocal results on an ELISA, IFA, or immunodot assay requires supplemental te sting with a Western blot assay. A negative result on the Western blot or E LISA indicates that there is no serologic evidence of infection by B burgdo rferi at the time the sample was drawn.