Case Study #7   1  2  3  4  5  6  7  8  9  10  11  12  13  Laboratory Evaluation of Suspected Encephalitis CSF PCR STRATEGY urgent diagnosis needed to validate proper therapy isolation of HSV from culture is the reference method for diagnosis DNA PCR on CSF obtained by lumbar puncture is becoming the gold standard DFA performed on brain touch prep in the current case (LP contraindicated due to possible herniation risk comprehensive virus isolation from brain within days confirmed HSV-1 METHODS lyse virions and extract DNA PCR with two sets of primers pol gene of HSV, 179 bp amlpicon glycoprotein B gene of HSV, 148 bp amplicon does not amplify CMV, VZV, HHV 6 cut pol amplicons with HhaI cleaves HSV-1 amplicon at a single site, two fragments cleaves HSV-2 amplicon at two sites, three fragments separate products on agarose gel with EtBr NIAID Collaborative Antiviral Study Group. J Infect Dis 171:857, 1995 Tang Y-W et al. J Clin Microbiol 37:2127, 1999   Biopsy + Biopsy - PCR + 53 3 PCR - 1 44 sensitivity 98% specificity 94% positive predictive value 95% negative predictive value 98% NIAID Collaborative Antiviral Study Group. J Infect Dis 171:857, 1995