Table 3. Comparative diagnostic accuracy of intra-individual robust coefficient of variation for peripheral blood neutrophil myeloperoxidase expression between a single-use flow cytometric lyophilised reagent tube (BD Lyotube Stain 468) and its laboratory-developed liquid reagent counterpart (n=100)*.
| BD Lyotube Stain 468 | Laboratory-developed liquid reagent test | |||
|---|---|---|---|---|
| Intra-individual RCV, median (range), % | ||||
| Confirmed suspicion of MDS (n=37) | 34.9 | (25.0–69.4) | 34.5 | (25.9–60.3) |
| Unconfirmed suspicion of MDS (n=63) | 29.0 | (23.8–44.6) | 29.8 | (23.9–48.5) |
| RCV≥30% | ||||
| True positive, n | 33 | (…) | 35 | (…) |
| False positive, n | 23 | (…) | 29 | (…) |
| False negative, n | 4 | (…) | 2 | (…) |
| True negative, n | 40 | (…) | 34 | (…) |
| Sensitivity, % (95% CI) | 89 | (75 to 97) | 95 | (82 to 99) |
| Specificity, % (95% CI) | 63 | (50 to 75) | 54 | (41 to 67) |
| PPV, % (95% CI) | 59 | (45 to 72) | 55 | (42 to 67) |
| NPV, % (95% CI) | 91 | (78 to 97) | 94 | (81 to 99) |
| LR+ (95% CI) | 2.44 | (1.73 to 3.45) | 2.05 | (1.56 to 2.71) |
| LR− (95% CI) | 0.17 | (0.07 to 0.44) | 0.10 | (0.03 to 0.39) |
*
The analytical sample consisted of 37 confirmed and 63 unconfirmed suspicions of myelodysplastic neoplasm, after excluding three patients with uninterpretable bone marrow cytomorphology.
LR+, likelihood ratio of a positive result; LR−, likelihood ratio of a negative result; MDS, myelodysplastic neoplasm; NPV, negative predictive value; PPV, positive predictive value; RCV, robust coefficient of variation.