TABLE 6.
Performance of the FilmArray ME panel for positive targets with and without the testing algorithma
| Result category | No. of specimens with result/total no. of specimens tested (%) |
||
|---|---|---|---|
| Without testing algorithm | With testing algorithm (repeat testing for all positive targets) | With revised testing algorithm (selective repeat testing)b | |
| All targets (n = 45) | |||
| TP reported | 41/41 (100) | 38/41 (92.7) | 41/41 (100) |
| FP reported | 4/4 (100) | 1/4 (25) | 1/4 (25) |
| FP avoided | 0/4 (0) | 3/4 (75) | 3/4 (75) |
| PPV | 41/45 (91.1) | 38/39 (97.4) | 41/42 (97.6) |
| FN generated | NA | 3c /41 (7.3) | 0c /41 |
| Viral targets (n = 33) | |||
| TP reported | 33/33 (100) | 31/33 (93.9) | 33/33 (100) |
| FP reported | 0/0 (0) | 0/0 (0) | 0/0 (0) |
| FP avoided | NA | NA | NA |
| PPV | 33/33 (100) | 31/31 (100) | 33/33 (100) |
| FN generated | NA | 2/33 (6.1) | 0/33 |
| Nonviral targets (n = 12) | |||
| TP reported | 8/8 (100) | 7/8 (87.5) | 8/8 (100) |
| FP reported | 4/4 (100) | 1/4 (25) | 1/4 (25) |
| FP avoided | 0/4 (0) | 3/4 (75) | 3/4 (75) |
| PPV | 8/12 (66.7) | 7/8 (87.5) | 8/9 (88.9) |
| FN generated | NA | 1c /8 (12.5) | 0c /8 (0) |
The reference result was based on concurrent conventional test results and clinical adjudication. Only those targets with concurrent conventional test results and that were successfully worked up per the testing algorithm were included in this analysis. TP, true positive; FP, false positive; PPV, positive predictive value; NA, not applicable.
Repeat testing only for bacterial targets with a negative Gram stain result and the C. neoformans/C. gattii target with negative Gram stain, calcofluor white, and CrAg test results. There was no repeat testing for positive viral targets.
One false-negative C. neoformans/C. gattii result was avoidable because it had a positive CrAg test result. Therefore, it was reported as a true positive in the revised testing algorithm.