Clinical Utility of the T2Candida Panel: A Real-World Analysis of More Than 2000 Cases.

Abstract

Objectives: Invasive candidiasis, including candidaemia, is associated with high morbidity and mortality. Diagnosis is traditionally based on blood culture, which lacks sensitivity. Therefore, additional tools such as PCR-based diagnostic methods are increasingly used. The T2MR technology is based on polymerase chain reaction and detection of the PCR product involving magnetic resonance technology. In this study, we compare the T2Candida in a clinical routine setting to conventional blood culture in order to explore its usefulness, strengths and weaknesses in its daily application.

Methods: This retrospective analysis was performed at the Vienna University Hospital with clinical routine samples submitted between April 2021 and May 2024. Sensitivity, specificity, positive predictive value, negative predictive value and accordance were calculated with blood culture as reference method. Patients with a positive T2Candida result but a negative result in blood culture were assessed according to a clinical case definition. Based on direct detection in blood by alternative methods (e.g. blood culture, alternative PCR), 1-3-beta-D-Glucan, patient risk factors and detection of the same species in other sample materials, each result was categorised as "proven", "probable", "possible", "improbable" or "not assessable".

Results: 2105 samples from 1447 unique patients were submitted for analysis during the study period. 94 samples were positive (4.5%) in the T2Candida, with 4 samples positive for more than one target. 26 out of these 94 (27.7%) were also positive in blood culture. 339 (16.1%) samples were invalid. The most frequent species detected was Candida albicans/tropicalis with 57 detections. Overall sensitivity of the T2Candida panel in our setting was 0.62 (95% CI 0.41-0.80) and specificity was 0.96 (95% CI 0.95-0.97). Cases detected by the T2Candida panel were assessed as proven (n = 28), probable (n = 11), possible (n = 29), improbable (n = 15) and not assessable (n = 15). Median time-to-result was 3.9 h for the T2Candida compared to a median time-to-positivity of blood culture ranging from 22.7 to 42.0 h depending on the species.

Conclusions: The introduction of the T2Candida panel led to a substantial rise in patients diagnosed with invasive candidiasis. Combination of both the T2Candida panel and conventional blood culture led to the detection of more positive samples than each test alone.