Herpes PCR Test in Kathmandu — Lesion PCR for Fresh Sores The Most Reliable Acute Diagnostic — ~2–12 Day Window on the Right Specimen

PCR on the Lesion — the Right Specimen for Acute Herpes

Herpes PCR — detecting viral DNA — is run on a swab from lesion itself: fresh blister or ulcer where virus is concentrated. It is most reliable acute herpes diagnostic — more sensitive than older viral culture — and correct test for question "is this lesion herpes" when a fresh sore is present.

The specimen distinction matters: PCR is on lesion, not blood — a blood test for herpes is serology (antibodies), a different test answering a different question (status vs lesion diagnosis). The two are sometimes confused; a positive serology does not prove a lesion is herpes, and a positive PCR does not give prior-status information.

The window is ~2–12 days of a fresh lesion — viral DNA declines as lesion heals, producing false negatives on older lesions. Attending while lesion is fresh is single most useful thing a suspected patient can do.

The Test — How It Works

A swab is taken across a fresh blister or ulcer — seconds, mildly uncomfortable at most — and laboratory amplifies any HSV DNA present. The typing distinguishes HSV-1 from HSV-2, which informs prognosis (HSV-2 recurs more often) and partner counselling.

A positive on a fresh lesion is definitive — virus is there. A negative on a healing lesion may be false — older lesion carries less virus — honestly stated rather than presented as a clean negative.

The ~2–12 Day Lesion Window

Viral DNA is abundant in a fresh lesion and declines as it heals — PCR works best within ~2–12 days of lesion appearing, with earliest fresh lesions strongest sample. The window is reason for "attend while fresh" — productive window closes as lesion heals.

The consequence: patients who wait for a convenient day arrive after productive window — a false negative on a healing lesion where a definitive answer was available days earlier.

PCR vs Serology

PCR and serology answer different questions: PCR answers "is this lesion herpes" (acute diagnosis); serology answers "have I been exposed to HSV-1 or HSV-2" (status). The commonest error is using serology to diagnose a lesion — a positive serology does not prove lesion because many people are seropositive from prior exposure.

The correct pairing: lesion present → PCR; no lesion but status wanted → serology (~3–12 week antibody window); very recent exposure + no lesion → neither is useful yet.

The Result & What Follows

A positive PCR confirms herpes with typing — result links to management at same service: episodic or suppressive antivirals, partner guidance (~50% transmission reduction with suppression, barrier-limit caveat), and honest counselling that puts common diagnosis in proportion.

A negative on a healing lesion is read honestly — possibly a false negative — with serology or a repeat-on-next-fresh-lesion advised rather than a false all-clear.

Herpes PCR & Costs

Transparent pricing; confirm when booking.

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