Genital Herpes Testing in Singapore: As genital herpes is caused by the herpes simplex virus, please refer to herpes simplex testing
LABORATORY INVESTIGATIONS
Viral isolation in cell culture
This is considered the ‘Gold standard’. The test is both sensitive and specific, but sensitivity declines as lesions heal; viral typing is possible.
Type-specific serological tests (TSSTs)
Based on recombinant type-specific glycoproteins gG1 (HSV-1) and gG2 (HSV-2). Good sensitivity and specificity and are useful in certain clinical situations e.g. confirming a diagnosis of genital herpes, counselling of sexual partners of infected persons, detection of unrecognised infection and for seroepidemiological studies. TSSTs are also useful in high risk populations such as MSM, individuals with multiple sex partners and HIV positive individuals. Screening for HSV-1 and HSV-2 in the general population is not indicated. Examples of these tests are HerpeSelect 1 and 2 ELISA (Focus Technologies, USA) and Immunoblot test kits.
As nearly all HSV-2 infections are sexually acquired, the presence of type-specific HSV-2 antibody implies anogenital infection. Most persons with HSV-1 antibodies have oral HSV infection acquired during childhood, which might be asymptomatic. The presence of HSV-1 antibody does not distinguish anogenital from orolabial infection.
HSV antigen detection
By Direct Immunoflouresence techniques. Results may be available in 1 to 2 days. HSV type is reported if the test is positive.
PCR detection of viral nucleic acid
Highest sensitivity viral typing possible; but expensive and not widely available. Test of choice for detecting HSV in spinal fluid.
Serology
Many commercial tests for HSV antibodies are not type specific and are of NO value in the management of genital herpes.