Evaluation of laboratory tests for diagnosis of chlamydial infections in conjunctival specimens.

ABSTRACT

We evaluated the chlamydial direct diagnostic tests and McCoy cell culture methods for detection of Chlamydia trachomatis in 234 conjunctival scrapings from 127 patients. Direct (rapid) diagnostic methods of Giemsa stain cytology, fluorescent antibody test (FAT) and immunoperoxidase (IPO) stain and McCoy cell culture isolation method using IPO staining and FAT for detection of C. trachomatis antigen were carried out. McCoy cell culture isolation using FAT antigen detection method was considered as the gold standard. The specificity of all the direct diagnostic tests were above 90 per cent but sensitivity of Giemsa cytology, FAT and IPO stain were 36, 54 and 53 per cent respectively showing that as direct diagnostic tests Giemsa stain cytology was inefficient and FAT and IPO were useful. Specificity and sensitivity of McCoy cell culture using IPO stain for detection C. trachomatis antigen were above 90 per cent and it is suggested that this test can be used as a routine diagnostic method.