Background: Diarrhea in solid organ transplant (SOT) recipients has been associated with allograft failure and mortality. Post-transplant diarrhea occurs frequently but the etiology is usually not identified. The purpose of the study was to assess the value of diagnostic tests for diarrhea by comparing cost and diagnostic yield on a population scale.
Methods: Single center retrospective chart review was conducted on SOT recipients admitted with community-acquired diarrhea from 1 March 2012 to 30 September 2013. A population-based binary classification analysis was performed to calculate the false omission rate (FOR). The FOR was calculated for the highest yield diagnostic test and repeated for each additional test in descending order. The total cost of each test was calculated. The decrease in FOR per cost was calculated for each additional test.
Results: Table 1 summarizes the results of the 422 admissions. The diagnostic tests with the highest yield were stool C. difficile toxin B PCR (60), serum quantitative CMV viral load PCR (31), and stool norovirus PCR (28). There was a minimal decline in the FOR with stool culture, blood culture, Giardia and Cryptosporidium EIA, and stool ova and parasite microscopy. The decrease in FOR per cost was larger for CMV compared to norovirus (Figure 1).
Conclusion: C. difficile and CMV tests should be sent during the routine evaluation of SOT recipients admitted for community-acquired diarrhea. Norovirus testing increases diagnostic yield but at a high cost. Additional diagnostic tests for diarrheal illness increase cost but do not improve the diagnostic yield.
Table 1. Cost and cumulative false omission rate of diagnostic tests for diarrhea in a SOT population
S. Penugonda, None
N. J. Rhodes, None
M. Angarone, None
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