Scoring more hits with HSV

Using PCR routinely would increase detection of HSV, according to Scoular et al, testing a LightCycler real time PCR protocol in a diagnostic laboratory serving a large genitourinary medicine clinic in Glasgow, Scotland.

Scoular et al compared performance with routinely used viral culture for identifying HSV. They took two swabs from suspect lesions of patients attending the clinic, one into viral transport medium for standard culture and typing, the other into lysis buffer. PCR was carried out on both samples with the LightCycler, using DNA primers for glycoprotein B gene of HSV-1 and HSV-2. Amplified HSV DNA was identified electronically by its melting point at 92.5°C (±0.5°C). PCR with a hybrid Omnigene was repeated to give sufficient DNA to identify HSV-1 and 2 by analysis of restriction fragments.

In all, 109 of 236 patients with paired samples were HSV positive by PCR or culture: 88 were PCR positive, culture positive; 21 PCR positive, culture negative; none were PCR negative, culture positive. PCR results were identical for swabs taken into transport medium or lysis buffer. The method was superior to culture in detecting more positives in vesicular (+13%), ulcerative (+27%), and crusting (+20%) lesions. All positive results yielded HSV-1 or 2.

LightCycler technology is considered suitable for diagnostic laboratory use: with it, overall detection rate went up by 24%, and its speed over conventional PCR gives a head start to advising patients and improving diagnostic perfromance.