LABORATORY EVALUATION IN THE DIAGNOSIS OF LYME-DISEASE

Purpose: To provide a quantitative and qualitative evaluation of the p redictive value of the laboratory diagnosis of Lyme disease and to use the resultant data to formulate guidelines for clinical diagnosis. Da ta Sources: A MEDLINE search of English-language articles or articles with English-language abstracts published from 1982 to 1996. Data Extr action: Sensitivity, specificity, and likelihood ratios were calculate d, and a random-effects model was used to combine the proportions from the eligible studies. Prespecified criteria were used to determine wh ich studies were eligible for analysis. Data Synthesis: Laboratory tes ting in general is not clinically useful if the pretest probability of Lyme disease is less than 0.20 or greater than 0.80. When the pretest probability is 0.20 to 0.80, sequential testing with enzyme-linked im munosorbent assay and Western blot is the most accurate method for rul ing in or ruling out the possibility of Lyme disease. Conclusions: Lab oratory testing is recommended only in patients whose pretest probabil ity of Lyme disease is 0.20 to 0.80. If the pretest probability is les s than 0.20, testing will result in more false-positive results than t rue-positive results; a negative test result in this situation effecti vely rules out the disease.