ANALYTICAL PERFORMANCE OF AN IMMUNOLOGICAL-BASED PERIODONTAL BACTERIAL TEST FOR SIMULTANEOUS DETECTION AND DIFFERENTIATION OF ACTINOBACILLUS-ACTINOMYCETEMCOMITANS, PORPHYROMONAS-GINGIVALIS, AND PREVOTELLA-INTERMEDIA

THE ANALYTICAL PERFORMANCE OF A MEMBRANE-BASED immunoassay for the sim ultaneous detection and differentiation of Actinobacillus actinomycete mcomitans, Porphyromonas gingivalis, and Prevotella intermedia (includ ing Prevotella nigrescens) was investigated. Positive reactions were o bserved for 71 of 71 reference strains and recent oral isolates of A. actinomycetemcomitans, P. gingivalis, and P. intermedia. No cross-reac tivity was observed with 39 other common oral and environmental specie s. The specificity of the test was unaffected by the presence of poten tial oral interferents including whole blood, white blood cells, mucin , saliva, toothpastes, and oral rinses. A proficiency test by dental p rofessionals using a standardized set of unknown simulated samples yie lded a sensitivity of 97% (116/120) and a 100% specificity (240/240). An additional group including dental professionals and high school stu dents was shown to be 99% proficient (1385/1397) in distinguishing pro per from improper test function when processing control samples with n ormal test devices and devices with simulated error conditions. Compar isons to a culture standard for 104 subgingival plaque samples collect ed from 26 adult periodontitis patients yielded > 98% specificity for each of the test bacteria. In addition, the detection threshold for th e test was determined to be equivalent to 104 cultivable test bacteria when compared to the culture standard. The data indicate that this me mbrane immunoassay is a valid and easy-to-use method for the detection of A. actinomycetemcomitans, P. gingivalis, and P. intermedia in subg ingival plaque, at levels above the detection threshold of the test.