title: Point-of-care test for detection of urogenital chlamydia in women shows low sensitivity. A performance evaluation study in two clinics in Suriname.
abstract: BACKGROUND
  In 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.
  
  
  METHODS
  Between 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.
  
  
  RESULTS
  CRT 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%).
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: STI Outpatient Clinic, Cluster Infectious Diseases, Public Health Service Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jannie J
authors.initials: JJ
authors.lastname: van der Helm
authors.forename: Leslie O A
authors.initials: LO
authors.lastname: Sabajo
authors.forename: Antoon W
authors.initials: AW
authors.lastname: Grunberg
authors.forename: Servaas A
authors.initials: SA
authors.lastname: Morré
authors.forename: Arjen G C L
authors.initials: AG
authors.lastname: Speksnijder
authors.forename: Henry J C
authors.initials: HJ
authors.lastname: de Vries
mesh_terms: D000328:Adult; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000235:genetics*; D005260:Female; D006801:Humans; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D019095:Point-of-Care Systems / Q000592:standards*; D011237:Predictive Value of Tests; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D012749:Sexually Transmitted Diseases / Q000175:diagnosis / Q000382:microbiology; D013532:Suriname; D014626:Vaginal Smears; D055815:Young Adult
chemical_list: D011934:Reagent Strips