Abstract
AIMS--To determine the sensitivity of commercially available diagnostic assays for Chlamydia trachomatis using a simple method. METHODS--Nine commercial assays and an "in-house" polymerase chain reaction (PCR) were evaluated using serial dilutions of a laboratory grown H serovar--four of them using a laboratory grown E serovar. Seven of the assays were further tested using dilutions of several cervical samples known to contain chlamydiae. RESULTS--The most sensitive assays were the MicroTrak direct fluorescent antibody (DFA) test (Syva) and the PCR which detected C trachomatis at a 10(-8) dilution of the H serovar, while the two least sensitive, Clearview (Unipath) and TestPack (Abbott), were positive only at 10(-4) and 10(-3) dilutions, respectively. A range of enzyme immunoassays (EIAs) and a nucleic acid hybridisation test were of intermediate sensitivity. The results with serovar E were consistent with these. When clinical samples were examined, the DFA test detected C trachomatis in dilutions at least 10-fold greater than any other assay. CONCLUSIONS--The range of sensitivity of diagnostic assays determined by the laboratory dilution procedure is very wide. Sensitivity assessed in this way, however, reflects the ability of the assays to detect C trachomatis in large scale clinical trials. The dilution procedure, which is simple to undertake, could therefore be applied by any laboratory before a new diagnostic method is considered for routine use.
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Selected References
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- Palmer H. M., Gilroy C. B., Thomas B. J., Hay P. E., Gilchrist C., Taylor-Robinson D. Detection of Chlamydia trachomatis by the polymerase chain reaction in swabs and urine from men with non-gonococcal urethritis. J Clin Pathol. 1991 Apr;44(4):321–325. doi: 10.1136/jcp.44.4.321. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taylor-Robinson D., Thomas B. J., Osborn M. F. Evaluation of enzyme immunoassay (Chlamydiazyme) for detecting Chlamydia trachomatis in genital tract specimens. J Clin Pathol. 1987 Feb;40(2):194–199. doi: 10.1136/jcp.40.2.194. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thomas B. J., Evans R. T., Hawkins D. A., Taylor-Robinson D. Sensitivity of detecting Chlamydia trachomatis elementary bodies in smears by use of a fluorescein labelled monoclonal antibody: comparison with conventional chlamydial isolation. J Clin Pathol. 1984 Jul;37(7):812–816. doi: 10.1136/jcp.37.7.812. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thomas B. J., Evans R. T., Hutchinson G. R., Taylor-Robinson D. Early detection of chlamydial inclusions combining the use of cycloheximide-treated McCoy cells and immunofluorescence staining. J Clin Microbiol. 1977 Sep;6(3):285–292. doi: 10.1128/jcm.6.3.285-292.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thomas B. J., Osborn M. F., Gilchrist C., Taylor-Robinson D. Improved sensitivity of an enzyme immunoassay IDEIA for detecting Chlamydia trachomatis. J Clin Pathol. 1989 Jul;42(7):759–762. doi: 10.1136/jcp.42.7.759. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thomas B. J., Osborn M. F., Munday P. E., Evans R. T., Taylor-Robinson D. A 2-year quantitative assessment of Chlamydia trachomatis in a sexually transmitted diseases clinic population by the MicroTrak direct smear immunofluorescence test. Int J STD AIDS. 1990 Jul;1(4):264–267. doi: 10.1177/095646249000100407. [DOI] [PubMed] [Google Scholar]