378. Utility of CMV Quantitative PCR in Tissue Biopsy for the Diagnosis of CMV Gastrointestinal Disease among Solid Organ Transplant Recipients

Abstract

Abstract Background Cytomegalovirus (CMV) infection is an important cause of morbidity after solid organ transplantation (SOT). Rapid and accurate diagnosis of gastrointestinal (GI) CMV disease is central to the early initiation of appropriate therapy. Currently, the diagnosis mainly relies on histopathology on formalin-fixed GI tissue biopsy. CMV diagnosis by quantitative polymerase chain reaction (qPCR) on tissue biopsy is not routinely performed for the diagnosis of tissue invasive disease, but potentially holds many practical advantages over the gold standard including a rapid turnaround time and providing a quantitative objective result. Methods We compared the performance of CMV qPCR on fresh GI biopsy with tissue biopsy histopathology for the diagnosis of GI CMV disease. Results A total of 62 SOT patients with GI symptoms underwent endoscopic assessment with GI biopsy analyses for both histopathology and tissue CMV qPCR. Twelve patients (19.4%) had proven CMV disease on histopathology. Among them, all had a positive qPCR on biopsy (median value of log 7.7 and 5.4 x107 copies/mL), and all had a positive serum CMV PCR (median value of log 4.5 and 3.4 x104 copies/mL). Of the 49 remaining patients with negative histopathology, 26 (53%) had CMV qPCR positive tissue biopsy specimens with a median log 4.3 and 2.0 x104 copies/mL. Of these 26 patients with histopathology negative/CMV qPCR positive tissue biopsies, 10 had positive serum CMV qPCR. Twenty-four patients were negative for all three tests: histopathology, CMV qPCR on tissue biopsy, and CMV viremia. ROC analysis for optimal threshold value for CMV qPCR on tissue biopsy for diagnosis of confirmed CMV GI disease is 104 824 copies/mL (sensitivity 100%, specificity 82%, area under ROC 0.91). Conclusion Our study shows that tissue biopsy CMV qPCR is highly sensitive (sensitivity of 100%) for the diagnosis of CMV GI disease. As such, tissue CMV qPCR may be a useful adjunctive diagnostic tool for the rapid diagnosis of CMV GI disease. Disclosures All Authors: No reported disclosures.