376. Testing for Cytomegalovirus Viremia in People with HIV/AIDS- An Opportunity for Diagnostic Stewardship

Abstract

Abstract Background Guidelines recommend against testing for cytomegalovirus (CMV) viremia as a screening tool for CMV end-organ disease (EOD) in people with HIV/AIDS (PWHA) due to low positive predictive value. Additionally, a negative result does not exclude EOD. In this study, we aim to assess the clinical utility of plasma CMV quantitative PCR (qPCR) for the diagnosis of CMV EOD and to determine if positive results lead to further testing for EOD or earlier initiation of anti-CMV therapy. Methods We retrospectively identified PWHA who had a plasma CMV qPCR result or who were diagnosed with CMV EOD between 2014-2021. qPCR results that were undetectable or less than the minimum quantifiable value (300 IU/mL) were considered negative and results >300 IU/mL were considered positive. EOD was confirmed via tissue biopsy, ophthalmic exam, or cerebrospinal fluid analysis. We compared CMV qPCR results for participants with proven EOD and those without proven EOD. For participants diagnosed with CMV EOD, we evaluated if a positive qPCR prompted further workup for EOD diagnosis or triggered anti-CMV therapy. Results We identified 138 PWHA with a CMV qPCR result and 17 PWHA with CMV EOD. Participant characteristics are shown in Table 1. Among participants with a qPCR result, 27 (19.6%) were positive; 13 (9.42%) of those with a qPCR results had EOD. 4 participants with EOD did not have qPCR. Participants with a positive qPCR were 4.55 (95% CI 2.63-7.90) times more likely to have EOD than those with a negative result. Table 2 shows qPCR results among participants with and without EOD. Table 3 shows the performance of qPCR for the diagnosis of EOD. 9 (69.2%) of 13 participants with EOD had a positive qPCR. 7 of them were diagnosed with EOD and started on treatment before the qPCR resulted. In 1 case, the qPCR resulted as positive on the same day ophthalmology diagnosed CMV retinitis. In only 1 case did a positive qPCR result and initiation of therapy precede the diagnosis of EOD. Conclusion Contrary to guidelines, clinicians often order plasma CMV qPCR on PWHA. Although PWHA who have CMV EOD are more likely to a have a positive qPCR than those without EOD, our data confirm CMV qPCR should not be used as a screening tool for EOD. Instead, clinical assessment should guide diagnostic investigation. Disclosures All Authors: No reported disclosures.