PMC:7558333 / 10771-12074
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3.3. Concordance of Diagnostic Tools
Table 4 gathers the results of the techniques used for Aspergillus detection. DNA detection by PCR showed the highest sensitivity, with a number of positive respiratory samples near twice higher, compared to the culture. Only one sample grew in culture, whereas PCR was negative, but the species obtained in culture was A. tubingensis (Nigri complex species), which is theoretically not amplified when using the 28S-targeted PCR specific for A. fumigatus. Interestingly, the correlation between cultural and molecular quantification showed a significant difference between the two techniques, with a mean Cq threshold of 32.6 ± 0.7 when cultures were negative, highlighting the higher sensitivity of PCR (Figure 1).
Overall, the concordance coefficient between PCR and culture on respiratory samples was 90.52% with a Cohen’s Kappa coefficient of 0.588. Regarding blood samples, three patients had a positive detection of a systemic biomarker: 3/3 had a positive PCR and 2/3 had a positive GM (Table 5). All three patients had a simultaneous detection of Aspergillus in respiratory samples by culture (n = 2) and/or PCR (n = 3). Overall, the concordance coefficient between PCR and culture on respiratory samples was 93.75% with a Cohen’s Kappa coefficient of 0.632.