TABLE 5.
Concordance between MALDI-TOF MS and standard identification methods across Biotyper consistency categoriesa
| Match category | Result (% concordance [95% confidence interval]) |
|||
|---|---|---|---|---|
| A | B | C | Overall | |
| Speciesb | 421/427 (98.6% [97.0–99.5]) | 47/54 (87.0% [75.1–94.6]) | 54/56 (96.4% [87.7–99.6]) | 522/537 (97.2% [95.4–98.4]) |
| Genusc | 427/427 (100% [99.1–100]) | 69/69 (100% [94.8–100]) | 55/56 (98.2% [90.4–100]) | 551/552 (99.8% [99.0–100]) |
| No reliable identificationd | 0/0 | 0/0 | 13/16 (81.3% [54.4–96]) | 13/16 (81.3% [54.4–96]) |
| Total | 427 | 69 | 72 | 568 |
The distribution of identifications by match category was significantly different across Biotyper consistency categories (P < 0.0001, Fisher's exact test).
Number of isolates concordant to species level with standard method identification/total number of isolates scoring ≥1.9.
Number of isolates concordant to genus level with standard method identification/total number of isolates scoring ≥1.7. Isolates scoring <1.7 were considered unreliable for identification by MALDI regardless of their concordance with standard method identification.
Number of isolates concordant to genus level with standard method identification/total number of isolates scoring <1.7. Isolates scoring <1.7 were considered unreliable for identification by MALDI regardless of their concordance with standard method identification.