Thore M, Faxelius G, Hedin G, Johnsson H, Ringertz S, Schröder S, Schwan A, Thid S, Ohrner Y
Department of Clinical Microbiology, County Hospital, Västerås, Sweden.
Acta Paediatr Scand. 1991 Feb;80(2):167-72. doi: 10.1111/j.1651-2227.1991.tb11829.x.
An open prospective multicenter study was conducted in order to evaluate the Wellcogen Strep B latex agglutination test in the diagnosis of group B streptococcal (GBS) infections in neonates. Twenty-three (5.9%) of 391 urine specimens and 5 (1.2%) of 404 sera assayed were positive. The results of the urine tests corresponded to a sensitivity of 0.78 for bacteremic, 0.50 for non-bacteremic and 0.53 for all GBS associated (bacteremic, non-bacteremic and suspected) infections. After 20-25-fold concentration of urine specimens the sensitivity increased to 1.0 for bacteremic, 0.67 for non-bacteremic and 0.78 for all GBS associated infections. The specificity of the test was high (0.93 for concentrated urines), and the predictive value of a positive test (Pvpos) was 0.68. A positive latex test was highly predictive of positive surface cultures for GBS (Pv pos = 0.83 after concentration).
