Sensitive immune dot blot test for diagnosis of Chlamydia trachomatis infection

Abstract

The sensitivity and specificity of an immune dot blot test (IDBT), which relies on a '251-labeled genus-specific monoclonal antibody to detect the Chlamydia lipopolysaccharide (LPS) antigen, were improved by pretreatment of specimens with proteinase K. This enzyme destroys protein A and therefore eliminates false-positive reactions caused by the presence of Staphylococcus aureus. Proteinase K treatment also improved the ability of the assay to detect the Chlamydia LPS antigen. When the improved IDBT was compared with culture for detection of C. trachomatis in 1,394 urogenital specimens obtained from a genitourinary medicine clinic, the overall sensitivity was 96%, and LPS antigen was detected in 76 of 83 (92%) specimens that yielded less than 10 inclusions in culture. The specificity and positive and negative predictive values of the test were 97, 81.5, and 99%, respectively. Of 123 conjunctival swabs, 7 were positive by both tests and 4 swabs were positive only by IDBT. This improved IDBT provides a simple, reliable alternative to culture for the detection of C. trachomatis in urogenital and conjunctival specimens.

Prospective study of adenovirus antigen detection in eye swabs by radioimmune dot-blot

“…A sample was considered reactive if the circle it produced was greater in intensity than the circle which corresponded to 25 tissue culture infectious dose -50 of adenovirus type 25 or 100 inclusion-forming units of Chlamydia trachomatis. 8 Incomplete circles or circles of lower intensity than these controls were interpreted as weakly positive reactions. If both reactions were positive, the more intense was classified as strongly positive.…”

Computer network for a diagnostic virology laboratory

“…In 1991, 52 405 specimens were received, I1 255 for virus detection, 14 595 for chlamydia detection, and 26 555 for virus serology. Tests in routine use include virus isolation in cell culture, respiratory virus antigen detection by immunofluorescence (Morris and Semple, 1990b), cytomegalovirus immediate early antigen detection (Morris et al, 1987) the polymerase chain reaction for the diagnosis of herpes simplex virus encephalitis adenovirus immune dot-blot (Killough et al, 1990) chlamydial isolation in cell culture and immune dot-blot (Mearns et al, 1988) electron microscopy including serotyping of faecal adenoviruses (Wood et al, 1989) rotavirus enzyme-linked immunosorbent assay, hepatitis A, B, C and D virus and human immunodeticiency virus (HIV) serological tests (Morris et al, 1990a), rubella and toxoplasma screening and serological diagnosis, complement fixation tests, screening for recent B 19 parvovirus infection (Rayment et al, 1990), and cytomegalovirus antibody tests on organ donors (Morris et al, 1990~).…”