Title: Various Laboratory Techniques for diagnosing Syphilis- A Comparative Study

Authors: Natesan Thilakavathi

 DOI: https://dx.doi.org/10.18535/jmscr/v7i3.96

Abstract

Aim: To compare the effectiveness of POCT and VDRL in the screening of syphilis among high risk group (HRG).

Methods and Material: The blood samples were collected from the HRGs' attending the STD OP of IOV from January 2010 to December 2010. The serum specimens from these blood samples were subjected to new point of care test (POCT – Rapid Specific Treponemal) test, Venereal Disease Research Laboratory (VDRL) / Rapid plasma Reagin (RPR) and Treponema pallidum haemagglutination (TPHA).

Statistical analysis used: SPSS version 10.0 and EPI 6 package, Chi-square test. To assess the statistical significance at 5% level, a two-sided test was considered.

Results: A total of 1131 High risk group (HRG) patients attended. Out of this, 599 (59%) were Men who have Sex with Men (MSM), 402 (35.5%) were Female sex worker (FSW), and 130 (15.5%) were Transgender (TG). The positivity rate of Syphilis was 68 among 599 (11.3%) in MSM, 33 among 400 (8.2%) in FSW and 17 among 130 (13%) in TG by POC test. The overall prevalence of syphilis by POCT test was 10.4% in HRG. The positivity rate of syphilis by VDRL test was 3.3(%) The concordance reactivity of the reactive serum sample tested by POC test was 89% with TPHA and was 33% with VDRL. If VDRL alone were used to screen Syphilis, 2/3 of the positive patients would be missed in this group.

Conclusions: The POCT test-screening method is highly sensitive, rapid, cost-effective, and easy to perform. Thus this treponemal test can be used to screen Syphilis to identify the true burden of disease in the community.

References

  1. Schwarb L. The Use of Rapid Syphilis Test WHO/TDR/2006.www.who.int/std diagnostics.
  2. Khan E, Memon BI, Ayaz A, et al. Trends of syphilis in Pakistan, 2008. Indian J Med Microbiol. 2010;28:263–264.
  3. Diaz T, Almeida MG, Georg I, Maia SC, De Souza RV, Markowitz LE. Evaluation of the determine rapid Syphilis TP assay using sera. Clin Diagn Lab Immunol. 2004;11(1):98–         
  4. Mayaud P, Mabey D. Approaches to the control of sexually transmitted infections in developing countries: old problems and modern challenges. Sexually Transm Infect.     2004;80:174–182.
  5. Muic V, Ljubicic M, Vodopija I. Bayes' theorem-based assessment of VDRL syphilis screening miss rates. Sex Transm Dis. 1999;26(1):12–16.
  6. Syphilis Testing a Review – Dr. Robert Notenboom Syphilis Review, 2004.
  7. Centers for Disease Control and Prevention (CDC). Discordant results from reverse sequence syphilis screening five laboratories, United States, 2006–2010. MMWR Morb         Mortal Wkly Rep. 2011 Feb 11;60(5):133–137.
  8. Sabibo M. Rapid point-of-care diagnostic test for syphilis in high risk populations, Manaus, Brazil. Emerg Infect Dis. 2009;15(4):647–649.
  9. Thappa DM. Sexually transmitted infection in India: current status. Indian J Dermatol. 2007;52(2):78–82.
  10. Benzaken AS, Sabido M, Galban EG, et al. Field evaluation of the performance and testing costs of a rapid point-of-care test for syphilis in a red-light district of Manaus, Brazil. Sex Transm Infect. 2008;84:297–302. http://dx.doi.org/10.1136/ sti.2007.029462.

Corresponding Author

Natesan Thilakavathi

Associate Professor, Department of Microbiology, Govt. Stanley Medical College, Chennai, India