From the Guidelines
Herpes testing should be performed using nucleic acid amplification test (NAAT) or polymerase chain reaction (PCR) diagnostic assays, which have high sensitivity and specificity, to detect HSV-1 or HSV-2 from a genital ulcer/lesion/suspected HSV outbreak. These tests are preferred over HSV culture due to their higher sensitivity, with most available tests having >90% sensitivity and specificity 1. When selecting a test, it is essential to choose an assay that differentiates between HSV-1 and HSV-2 infection to provide patients with information regarding the expected natural history of genital herpes.
Some key points to consider when testing for herpes include:
- NAAT/PCR assays should not be obtained in the absence of a genital ulcer to diagnose genital herpes infection, as the intermittent nature of genital HSV shedding may lead to false-negative results 1.
- HSV serologic assays should be performed in situations where NAAT/PCR is not possible or when a patient has no visible ulcers, as they can help diagnose HSV-1 and HSV-2 infection 1.
- Type-specific HSV serologic assays, such as those that target antibodies to HSV glycoprotein G-1 or HSV glycoprotein G-2, can differentiate between HSV-1 and HSV-2, but may have limitations, including lack of sensitivity for HSV-1 and specificity for HSV-2 1.
- The gold standard for HSV serologic testing is Western blot/immunoblot assays, which target antibodies to several HSV antigens, but may not be widely available 1.
In terms of testing strategies, the following are recommended:
- Testing should be performed within 48-72 hours of symptom onset for optimal results 1.
- Regular screening is not recommended for people without symptoms due to potential false positives and the psychological impact of diagnosis.
- Pregnant women with potential exposure should be tested to prevent transmission to the baby during delivery.
- Individuals with symptoms of herpes infection, such as painful blisters or sores in the genital area or mouth, or those who have had sexual contact with someone diagnosed with herpes, should be tested using NAAT/PCR or serologic assays 1.
From the Research
Herpes Testing Methods
- Type-specific testing to distinguish HSV-1 from HSV-2 is always recommended, as the type of herpes simplex virus infection affects prognosis and subsequent counseling 2, 3, 4.
- PCR (polymerase chain reaction) has a consistently and substantially higher rate of HSV detection and could replace viral culture as the gold standard for the diagnosis of genital herpes in people with active mucocutaneous lesions 2, 3, 4.
- Antigen detection, such as immunofluorescence test or enzyme immunoassay, can be employed, but HSV type determination is of importance 2, 3.
- Type-specific serology based on glycoprotein G should be used for detecting asymptomatic individuals, but widespread screening for HSV antibodies is not recommended 2, 4.
Importance of Accurate Diagnosis
- Accurate identification of persons with genital herpes is necessary for optimal patient management and prevention of transmission 3.
- Clinical diagnosis of genital herpes should be confirmed by laboratory testing for the causative agents herpes simplex virus type 1 (HSV-1) and HSV type 2 (HSV-2) 3.
- The clinical presentation of herpes simplex virus infection is influenced by the portal of entry, the immune status of the host, and whether the infection is primary or recurrent 5.
Management and Counseling
- Genital herpes can have a substantial impact during pregnancy and on sexual health in general, and counseling on natural history, transmission, treatment, and management of sexual partners is an integral part of management of genital herpes 6.
- Treatment decreases duration of symptoms and signs and can be provided as episodic or suppressive therapy 6.
- Counseling on the natural history of infection and risk of transmission is valuable for patients with genital herpes 3.