Comparison of nested-polymerase chain reaction and virus culture for the diagnosis of genital herpes simplex virus infection.

INTRODUCTION This study was performed to compare nested-polymerase chain reaction (PCR) with viral culture as a diagnostic tool for genital herpes simplex virus (HSV) infection in a sexually transmitted infection (STI) clinic in Singapore. METHODS 103 consecutive patients presenting with clinical features suggestive of genital herpes were enrolled in the study. Two swabs were obtained from each patient. On one swab, cell culture and typing was performed, and on the second swab, nested-PCR was performed and the infecting viral type was determined by using type-specific primers. RESULTS 63 patients (61.2 percent) had a positive PCR test for HSV. Of these, 13 patients (20.6 percent) had HSV type 1 (HSV-1), 50 patients (79.4 percent) had HSV type 2 (HSV-2). HSV-1 and HSV-2 were detected by viral culture in only six patients and 24 patients, respectively. The sensitivity of cell culture compared to PCR was 46.1 percent for HSV-1 infection and 48 percent for HSV-2 infection. PCR further detected an additional 52.4 percent of HSV cases. The specificity of PCR was 100 percent. CONCLUSION Nested-PCR has been shown in this study to be an effective diagnostic and typing method for HSV infection in a STI clinic in Singapore with its higher sensitivity and specificity to routine viral isolation in cell culture.