A Case of Frosted Branch Angiitis in the Age of Polymerase Chain Reaction: Diagnostic and Therapeutic Considerations.

To describe a unique case highlighting the limitations and caveats of multiplex polymerase chain reaction (mPCR) in the diagnosis of posterior infectious uveitis, specifically frosted branch angiitis (FBA), we present a case of FBA in which multiple diagnostic modalities, including mPCR, are inconclusive. A thorough literature review was carried out to discuss the validity of mPCR in the setting of posterior infectious uveitis, the theoretical effect of sample dilution, and to explore a management strategy in these difficult cases. It is known that mPCR has high sensitivity and specificity, with a low false negative rate. However, the rate of false negatives appears to increase in cases of FBA, and when samples are diluted. In such cases we suggest empiric treatment be initiated and targeted towards microorganisms most likely to be implicated based on exam and history.