UMMS Affiliation

Department of Family and Community Medicine

Date

7-1-1990

Document Type

Article

Subjects

Adult; Antigens, Bacterial; Chlamydia Infections; Chlamydia trachomatis; Diagnostic Errors; Evaluation Studies as Topic; Female; Fluorescent Antibody Technique; Humans; Immunoenzyme Techniques; Pregnancy; Pregnancy Complications, Infectious; Seroepidemiologic Studies

Disciplines

Clinical Epidemiology | Community Health and Preventive Medicine | Primary Care

Abstract

We compared a direct fluorescent-antibody stain (DFA) and an enzyme immunoassay (EIA) with a standard cell culture technique for the detection of Chlamydia trachomatis infection in women in an urban family practice setting. We also evaluated a DFA sample in a commercial laboratory to determine the interlaboratory reliability of this test. There were 268 women in the study; the EIA provided a higher sensitivity (83 versus 50%) and a higher positive predictive value (83 versus 69%) than the DFA test and comparably high specificity (99 versus 98%). Concordance between the two laboratories on the DFA test was not high when data were adjusted for chance agreement (kappa coefficient = 0.64). DFA validity was optimal with an elementary body cutoff of greater than 5, while EIA validity was optimal at the recommended cutoff of 0.1 optical density unit. None of 11 women with negative cultures after treatment had false-positive antigen tests. False-negative results with both tests were associated with low culture inclusion counts but were not strongly associated with the presence or absence of symptoms, menses, pregnancy, or recent antibiotic use. False-positive results with EIA were seen only for three women who had a chief complaint of vaginal discharge. Although the positive predictive value of DFA could be increased in high-prevalence subpopulations, EIA was still more valid in two such groups: teenagers and prenatal patients. These results indicate that EIA might be preferable for low- or moderate-prevalence populations in primary care settings and that a falloff in DFA sensitivity could be explained by lower infection burdens in low-prevalence groups.

Rights and Permissions

Citation: J Clin Microbiol. 1990 Jul;28(7):1580-5.

Related Resources

Link to Article in PubMed

Journal Title

Journal of clinical microbiology

PubMed ID

2199520

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