Background: Candidemia is a common hospital-acquired infection that is associated with high mortality. Diagnosis via blood cultures (BC) is limited by poor sensitivity (50%) and slow turnaround time (2-5 days). T2Candida (T2C) is a newly available rapid test using magnetic resonance that can detect 5 species of Candida from whole blood in < 6 hrs with a sensitivity of 91.1%.
Methods: We performed a retrospective analysis of all cases of candidemia detected by BC and/or T2C during 2016 at UAB Medical Center. The test was targeted to ICU patients (pts) who had higher risk criteria for candidemia. We collected APACHE II scores at the time of BC or T2C test collection as a surrogate for severity of illness. Other outcomes included 30-day mortality and time to initiation of therapy (TTT).
Results: We identified 139 pts with candidemia, defined as a positive BC (BC+) and/or positive T2C (T2C+). Performance of a single test led to diagnosis in 103 patients (74%). On initial diagnosis if both a BC and T2C were performed within a 24 hour interval, pts were grouped based on the results of both tests. 36 pts (26%) had both tests performed: 8/36 (22%) were concordant (BC+/T2C+) and 28/36 (78%) discordant. 23/28 pts (82%) with discordance were BC-/T2C+ and the remaining 5 were BC+/T2C-. The difference in APACHE II scores and 30-day mortality rate of BC+ pts (13.6, 0.36) and T2C+ pts (16.4, 0.46) were not significant (p-values 0.06 and 0.29 respectively); the difference in TTT between BC+ pts (1.6 d) and T2C+ pts (0.1 d) was statistically significant (p-value < 0.00001).
Conclusion: T2C demonstrated excellent sensitivity (88.6%) in a real world setting focused in the ICU. We observed a significant reduction in TTT associated with the T2C assay, but did not observe an improvement in survival with earlier therapy for candidemia defined as a T2C+. Pts with T2C+ had higher APACHE II scores suggesting biased testing towards sicker pts. We cannot explain the large number of discordant results (BC-/T2C+, BC+/T2C-), but hypothesize that T2C+ may be a more sensitive marker for invasive candidiasis/candidemia. These data strongly endorse the need for a large, prospective, multicenter study exploring the use of T2C vs. standard of care in the diagnosis and management of this disorder.
O. D. Turner,
T. P. McCarty, None
M. Manning, None
C. J. Hoesley, None
P. G. Pappas, T2Candida Panel: Grant Investigator and Scientific Advisor , Grant recipient , Research grant and Research support
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