Point-of-Care Test for Detection of Urogenital Chlamydia in Women Shows Low Sensitivity. A Performance Evaluation Study in Two Clinics in Suriname

Abstract

BackgroundIn general, point-of-care (POC) tests for Chlamydia trachomatis (Ct) show disappointing test performance, especially disappointing sensitivity results. However, one study sponsored by the manufacturer (Diagnostics for the Real World) reported over 80% sensitivity with their Chlamydia Rapid Test (CRT). We evaluated the performance of this CRT in a non–manufacturer-sponsored trial.MethodsBetween July 2009 and February 2010, we included samples from 912 women in both high- and low-risk clinics for sexually transmitted infections (STIs) in Paramaribo, Suriname. Sensitivity, specificity, positive- and negative predictive values (PPV and NPV) for CRT compared to NAAT (Aptima, Gen-Probe) were determined. Quantitative Ct load and human cell load were determined in all CRT and/or NAAT positive samples.ResultsCRT compared to NAAT showed a sensitivity and specificity of 41.2% (95% CI, 31.9%–50.9%) and 96.4% (95% CI, 95.0%–97.5%), respectively. PPV and NPV were 59.2% (95% CI, 47.5%–70.1%) and 92.9% (95% CI, 91.0%–94.5%), respectively. Quantitative Ct bacterial load was 73 times higher in NAAT-positive/CRT-positive samples compared to NAAT-positive/CRT-negative samples (p<0.001). Human cell load did not differ between true-positive and false-negative CRT results (p = 0.835). Sensitivity of CRT in samples with low Ct load was 12.5% (95% CI, 5.2%–24.2%) and in samples with high Ct load 73.5% (95% CI, 59.9%–84.4%).ConclusionsThe sensitivity of CRT for detecting urogenital Ct in this non–manufacturer-sponsored study did not meet the expectations as described previously. The CRT missed samples with a low Ct load. Improved POC are needed as meaningful diagnostic to reduce the disease burden of Ct.

Point-of-care management of urogenitalChlamydia trachomatisvia Gram-stained smear analysis in male high-risk patients. Diagnostic accuracy and cost-effectiveness before and after changing the screening indication at the STI Clinic in Amsterdam

“…Although not excluded, most MG infections are symptomatic; the organism is found in only 5–6% of asymptomatic men 16 17. Likewise, urogenital infections caused by herpes simplex virus and adenovirus are to cause symptoms more frequently than on average in bacterial related NGU 5. These non-detected pathogens can further explain the low specificity found in the study.…”

“…Recently, several companies have developed lipopolysaccharide based POC tests that provide rapid results for the detection of CT. However, low sensitivity (25–65%) precludes more widespread use in clinical settings 4 5…”

Spontaneous pharyngealChlamydia trachomatisRNA clearance. A cross-sectional study followed by a cohort study of untreated STI clinic patients in Amsterdam, The Netherlands

“…In the same samples, the number of human leucocyte antigen (HLA) copies was determined using a quantified serial dilution. The chlamydia/human cell ratio (chlamydial DNA concentration) was calculated as described previously16 and expressed as IFU/100 million HLA copies. As the majority of PhCT samples tested negative in the less sensitive real-time PCR, analysis on a linear scale had very limited power.…”

Diagnosis and Management of UncomplicatedChlamydia trachomatisInfections in Adolescents and Adults: Summary of Evidence Reviewed for the 2015 Centers for Disease Control and Prevention Sexually Transmitted Diseases Treatment Guidelines

“…Van Dommelen et al evaluated the performance of 3 CT POC tests on vaginal swabs compared with CT PCR and found that with CT PCR as the reference standard, the sensitivities of the Handilab-C test, Biorapid CHLA-MYDIA Ag test, and QuickVue Chlamydia test were 12%, 17%, and 27%, respectively, whereas the specificities were 92%, 93.5%, and 99.7%, respectively [60]. Van der Helm et al evaluated the performance of the Chlamydia Rapid Test on vaginal swabs compared with CT TMA and found that with TMA as the reference standard, the Chlamydia Rapid Test had a sensitivity of 41.2% and specificity of 96.4%; they further stratified sensitivity by CT load and found that the sensitivity of the Chlamydia Rapid Test was 12.5% with a low CT load and 73.5% with a high CT load [61]. Nadala et al evaluated the performance of the Chlamydia Rapid Test on urine in men compared with CT PCR and found that with PCR as the reference standard, the Chlamydia Rapid Test had a sensitivity of 82.6% and specificity of 98.3% [62]; however, women were not studied, and some authors were affiliated with the Chlamydia Rapid Test manufacturer.…”