Diagnostic Testing and Co‑Infection Screening for Recurrent Genital HSV

Specimen Collection for HSV PCR

Open vesicles with a sterile needle, collect vesicular fluid using a cotton‑wool or Dacron swab, and vigorously swab the lesion base to obtain epithelial cells – this technique maximizes viral DNA recovery for nucleic acid amplification testing. 1
Obtain specimens as early as possible in the disease course; vesicular lesions yield significantly higher PCR positivity than ulcerated or crusted lesions. 1
When external lesions are absent, collect cervical and vaginal wall swabs; HSV can be isolated from these sites in the majority of women with genital infection. 1

Screen all patients with genital HSV for Chlamydia trachomatis and Neisseria gonorrhoeae using NAAT on a vaginal swab (preferred specimen for women). 2
Perform syphilis serology with a reverse algorithm (treponemal EIA/chemiluminescence followed by RPR confirmation). 2
Use a fourth‑generation HIV antibody/antigen assay, which detects infection 2–4 weeks after exposure. 2
Include Trichomonas vaginalis NAAT for sexually active women, especially those under 25 years or with multiple partners. 2
HSV and Treponema pallidum can be recovered from the same genital lesion, making laboratory differentiation essential. [1][3]
Approximately one‑quarter to two‑thirds of genital infections remain unidentified despite standard testing, underscoring the need for a comprehensive STI panel. [4][2]
Inflammatory epithelium from HSV lesions increases HIV transmission risk, providing further rationale for routine HIV screening. 2

Retest for Chlamydia and Gonorrhea three months after any positive result, regardless of partner treatment, because reinfection rates range from 25 % to 40 %. 4
Offer annual screening for Chlamydia, Gonorrhea, HIV, and Syphilis to all sexually active women under 25 years; increase testing frequency to every 3–6 months for those with ongoing high‑risk behaviors. 4
For HIV‑positive patients, perform bacterial STI screening (Chlamydia, Gonorrhea, Syphilis, Trichomoniasis) every 3–6 months. 4

Do not rely on clinical diagnosis alone; 80 %–90 % of genital herpes infections are subclinical, making clinical findings neither sensitive nor specific. [1][4]
Avoid viral culture as first‑line testing; nucleic acid amplification testing is substantially more sensitive, especially for recurrent or ulcerated lesions. (Supported by cited evidence on PCR superiority).
Do not use Tzanck smear, which has low sensitivity/specificity and cannot differentiate HSV from varicella‑zoster virus.
Do not omit extragenital testing (rectal, pharyngeal) in high‑risk populations, as these sites frequently harbor asymptomatic infections. 2
Ensure partner notification and treatment; most apparent “treatment failures” are actually reinfections from untreated partners. [4][2]

For a patient presenting with a genital rash, immediately obtain a swab from any visible lesions for nucleic acid amplification testing (NAAT/PCR) with HSV typing, as this provides the highest sensitivity and specificity (>90%) and is the preferred diagnostic method, according to the Clinical Infectious Diseases guidelines 5
The American College of Physicians and the Infectious Diseases Society of America recommend collecting specimens as early as possible in the disease course, as vesicular lesions yield significantly higher positivity rates than ulcerative or healing lesions 5
The specimen collection technique should involve opening vesicles with a sterile needle, collecting vesicular fluid content with a cotton-wool or Dacron swab, then vigorously swabbing the base of the lesion to obtain epithelial cells, as recommended by Eurosurveillance 6
The Centers for Disease Control and Prevention recommend requesting NAAT/PCR with HSV typing (HSV-1 vs HSV-2 differentiation), as this is critical for counseling—12-month recurrence rates differ dramatically: HSV-2 (90%) versus HSV-1 (55%), according to Clinical Infectious Diseases 5

Clinical diagnosis alone is unreliable—laboratory confirmation should always be sought, as genital HSV infection is difficult to differentiate from other causes of genital ulceration, according to Eurosurveillance 6
The World Health Organization recommends considering and testing for other sexually transmitted infections, such as Treponema pallidum (syphilis) and Haemophilus ducreyi (chancroid), as these can present similarly to genital herpes, according to Eurosurveillance 6

Type-specific HSV serology (glycoprotein G-based) should be reserved for specific situations, such as when lesions have healed and NAAT/culture was not obtained, or to distinguish between HSV-1 and HSV-2 in patients with a history of genital herpes but no current lesions, according to Clinical Infectious Diseases 5
The Infectious Diseases Society of America notes that HSV-1 EIA/CLIA assays have only 70.2% sensitivity, resulting in frequent false-negatives, and HSV-2 EIA/CLIA assays lack specificity, particularly with index values 1.1–2.9 (only 39.8% specificity), according to Clinical Infectious Diseases 5

For women with genital lesions, the Centers for Disease Control and Prevention recommend collecting specimens from the cervix and vaginal wall, as HSV can be isolated from these sites in 88% and a significant proportion of women with first-episode genital herpes, respectively, according to Eurosurveillance 6
For men with genital lesions, the European Centre for Disease Prevention and Control suggests considering urethral sampling if urethral discharge is present, as HSV can be isolated from the urethra in 28% of men with first-episode infection, according to Eurosurveillance 6