TABLE 1.
Performance of modified Kinyoun acid-fast staining processed with filter water, tap water, and deionized water
| Processing water and culture status | No. of smears
|
%
|
||||
|---|---|---|---|---|---|---|
| Positive | Negative | Sensitivity | Specificity | PPVa | NPVb | |
| Filterc | 44.3 | 98.6 | 83.3 | 91.5 | ||
| Positive | 35 | 44 | ||||
| Negative | 7 | 476 | ||||
| Tap | 51.9 | 87.6 | 40.6 | 91.8 | ||
| Positive | 41 | 38 | ||||
| Negative | 60 | 423 | ||||
| Deionized | 53.2 | 89.9 | 46.2 | 92.1 | ||
| Positive | 42 | 37 | ||||
| Negative | 49 | 434 | ||||
a
Proportion of specimens with positive culture results which are correctly detected by smear.
b
Proportion of specimens with negative culture results which are correctly detected by smear.
c
P values for sensitivity, specificity, PPV, and NPV in comparison with tap water are 0.17, <0.001, <0.001, and 0.45, respectively, and in comparison with deionized water are 0.13, <0.001, <0.001, and 0.36, respectively.