These guidelines aim to provide comprehensive information about sexually transmitted herpes simplex virus (HSV) infection and its laboratory diagnosis in eastern European countries. They are primarily intended for professionals testing specimens from patients at a sexual healthcare clinic but may also be helpful for community-based screening programmes. In particular, the guidelines recommend: (i) either viral culture or validated and approved nucleic acid amplification tests (NAATs) as the tests of choice for symptomatic patients, which should be promoted for laboratory confirmation of HSV infection; (ii) if culture or NAATs are not available, antigen detection--a direct immunofluorescence test or enzyme immunoassay from samples from symptomatic patients--could be employed, but HSV type determination is of importance; (iii) only type-specific serology should be used for detecting asymptomatic individuals, testing pregnant women at risk of acquiring HSV infection close to delivery, men who have sex with men and people who are HIV positive; (iv) widespread screening for HSV antibodies should be discouraged; and (v) any non-validated diagnostic tests should be validated against a recommended, approved gold standard.