Identification of pathogenic Neisseria species with the RapID NH system

The RapID NH system (Innovative Diagnostics Systems, Inc., Decatur, Ga.) is a 4-h test used in the identification of Neisseria and Haemophilus species. The system was evaluated for accuracy and reliability and compared with conventional (cystine proteose peptone agar; Prepared Media Laboratory, Tualatin, Ore.) carbohydrate degradation tests with Neisseria gonorrhoeae and N. meningitidis, as well as a variety of Neisseria, Branhamella, and Moraxella species. The RapID NH system correctly identified all N. gonorrhoeae, N. meningitidis, and N. lactamica isolates, but the level of accuracy varied considerably for the remaining organisms. One strain of N. subflava was misidentified as a pathogenic Neisseria strain. The RapID NH tests were concluded in 4 h, whereas the cystine proteose peptone agar tests required up to 48 h for results to be useful. The RapID NH system is an accurate, reliable, and useful method for the identification of pathogenic Neisseria species. It has been proven that it shortens identification time and specimen turnaround time by at least 24 h.