Abstract
Purpose::
Microbiology results are a useful adjunct to clinical evaluation in guiding treatment of ophthalmic infectious diseases, such as herpes simplex virus (HSV). Frequently, a discrepancy exists between HSV polymerase chain reaction (PCR) and the "gold standard" HSV cell culture results. The purpose of this study is to investigate the clinical diagnosis given to those patients with discrepant HSV PCR and viral cell culture results in order to interpret which result correlates clinically.
Methods::
A retrospective review of laboratory requisitions from July 2004 to November, 2006 yielded fifty positive HSV PCR results. Testing for PCR and A549 cell culture were processed on samples of conjunctiva, cornea or intraocular fluid that had been transported in 2.0 ml of Bartels Chlamydial medium.
Results::
Twenty-one of 50 patients (42%) had negative HSV cell culture and positive PCR results and the remaining 29 patients (58%) had both positive PCR and cell culture results. Sixteen of the positive PCR-negative culture patients and 21 of the positive PCR-positive culture patients had documented clinical evaluations and diagnoses. Of these sixteen patients with positive HSV PCR results and negative HSV cell cultures, fourteen (88%) carried a clinical diagnosis of herpes simplex: 12 diagnoses of HSV keratitis or keratouveitis, 1 diagnosis of HSV conjunctivitis, and 1 diagnosis of Acute Retinal Necrosis. Of the 21 patients with positive PCR and cell culture results, 100% carried a diagnosis of HSV. There were no cases of negative PCR results with positive culture results. All clinically diagnosed cases of HSV were treated and improved on either acyclovir or valacyclovir.
Conclusions::
PCR had greater sensitivity in detecting clinically diagnosed and treated ophthalmic cases of HSV that cell culture missed.
Keywords: herpes simplex virus • clinical laboratory testing