Published online Sep 30, 2006.
https://doi.org/10.4111/kju.2006.47.9.978
Evaluation of a Rapid Test for Detection of Chlamydia Trachomatis Infection in Female Commercial Sex Workers
Abstract
Purpose
The importance of laboratory screening tests for female commercial sex workers (FCSWs) has been well documented to reduce the prevalence of chlamydial complications. A rapid test has been one of the standard chlamydial tests performed in Korean health centers. Although the process of the rapid test is simple, the sensitivity is inconsistent. Therefore, we evaluated the efficacy of QuickVue chlamydial detection kits, which is one of the rapid tests, by comparing this assay to an in-house polymerase chain reaction (PCR) method.
Materials and Methods
A total of 410 endo-cervical samples were consecutively collected in one health center. A rapid test was performed by using a QuickVue kit. Genomic DNA was extracted from cotton swabs. The cryptic plasmid of C. trachomatis from the genomic DNA was amplified by the PCR method.
Results
The overall sensitivity, specificity, positive predictive value and negative predictive value of the rapid test were 21%, 99%, 89% and 83%, respectively, based on the PCR results. Study of the serial dilutions of reference inclusion forming units (IFU) showed that the rapid test only detected chlamydial infections that had high counts of IFUs.
Conclusions
The rapid test is not good enough to detect chlamydial infection in FCSWs. Instead, a gene amplification test should be used for detecting chlamydial infections in FCSWs.
Fig. 1
Serial dilution study for determining the sensitivity of the rapid test show a positive band in the test line (short arrow) in the one-time diluted test drops. All three samples show positive bands in the control lines (long arrow). The positive controls are from formalin-inactivated Chlamydia and the negative control is from heat-activated group B Streptococcus.
Fig. 2
The polymerase chain reaction test shows a very strong band at serial dilutions of 10, 5, 1 and even 1µl of the 102d diluted template volume. 1µl of 103d dilution means 1µl of the original template is diluted to 1:1,000 and 1µl of the diluted template is added to the polymerase chain reaction mixture for amplification. Marker: 100bp DNA ladder marker (Promega, USA).
Table 1
Comparison the results of the rapid test and the PCR* method
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