From the Guidelines
Diagnosis of genital herpes should be based on a combination of clinical examination and laboratory testing, with PCR tests being the most accurate method for detecting viral DNA from a swab of an active lesion, as recommended by the 2021 Centers for Disease Control and Prevention (CDC) STI treatment guidelines 1. When suspecting genital herpes, it is essential to see a healthcare provider who will examine the affected area for characteristic lesions, which appear as painful blisters or ulcers.
- The most accurate diagnostic method is a PCR test, which detects viral DNA from a swab of an active lesion.
- Viral culture is another option but is less sensitive than PCR, with a lower sensitivity that decreases as genital ulcers heal 1.
- Blood tests can detect antibodies to HSV-1 and HSV-2, indicating past infection, but may not distinguish between oral and genital infections.
- Type-specific glycoprotein G-based assays (IgG) are preferred as they can differentiate between HSV-1 and HSV-2, with the gold standard for HSV serologic testing being Western blot/immunoblot assays 1. Key considerations for diagnosis include:
- Testing is most accurate when lesions are present, ideally within the first 48 hours of symptoms.
- False negatives can occur if lesions have begun healing.
- If symptoms like painful genital sores, burning, itching, or flu-like symptoms are experienced, seeking medical attention promptly for proper diagnosis and treatment is crucial. Early diagnosis allows for appropriate antiviral therapy, which can reduce symptom severity and duration, and is essential for managing genital herpes infection, as outlined in the 2021 CDC STI treatment guidelines 1.
From the Research
Diagnostic Criteria for Genital Herpes (HSV) Infection
The diagnostic criteria for genital herpes (Herpes Simplex Virus, HSV) infection involve a combination of clinical presentation and laboratory studies 2, 3, 4, 5, 6.
- Clinical diagnosis should be confirmed by laboratory testing, which can include:
- Viral culture
- Polymerase chain reaction (PCR)
- Antigen detection
- Type-specific serology (TSS)
- Type-specific testing to distinguish HSV-1 from HSV-2 is always recommended, as the type of HSV infection affects prognosis and subsequent counseling 3, 4, 6.
- PCR has a 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 4.
- Antigen detection, such as immunofluorescence test or enzyme immunoassay, can be employed, but HSV type determination is of importance 4.
- Type-specific serology based on glycoprotein G should be used for detecting asymptomatic individuals, but widespread screening for HSV antibodies is not recommended 4.
Laboratory Diagnostics
Laboratory diagnostics play a crucial role in the diagnosis of genital herpes, allowing for the clear establishment of the etiology (HSV-1 or HSV-2) and determination of the course of infection and prognosis 2.
- The selection of the appropriate test depends on factors such as diagnostic goals, patient population, specimen type, and implementation of conditions for the specific method 2.
- PCR has been shown to have high sensitivity and specificity in detecting HSV-1 and HSV-2 DNA in clinical samples 2, 3.
- Viral culture can also be used, but it may not detect viral DNA in all cases 2.
Importance of Accurate Diagnosis
Accurate identification of persons with genital herpes is necessary for optimal patient management and prevention of transmission 3.