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R.T. Silver and S. Krichevsky
(Table 2). Figure 1A shows ROC curves for HCT in men and women with ETJAK2V617F and PV; Figure 1B shows this for HGB concentration and Figure 1C shows this for RBC counts. The computer-calculated area under the curve (AUC) measures how well ETJAK2V617F and PV patients are distinguished using HCT, HGB, or RBC. AUC ranges from 0 to 1, inclusive, with 1 representing a perfectly specific and sensitive test. For men, the AUC for HCT is 0.819 (specificity=100.0%, sensitivity=64.4%) indicating that by using this sole criterion, 100.0% of male ETJAK2V617F patients, but only 64.4% of male PV patients, would be correctly diagnosed. For men, the AUC for HGB is 0.753
(specificity=100.0%, sensitivity=62.8%) indicating that 100.0% of male ETJAK2V617F patients, but only 62.8% of male PV patients, would be correctly diagnosed. For men, the AUC for RBC is 0.761 (specificity=100.0%, sensitivi- ty=52.5%) indicating that 100.0% of male ETJAK2V617F and 52.5% of male PV patients would be correctly diagnosed. For women, the AUC for HCT is 0.957 (specifici- ty=100.0%, sensitivity=71.1%), for HGB 0.875 (specifici- ty=88.9%, sensitivity=75.0%), and for RBC 0.924 (speci- ficity=81.5%, sensitivity=87.1%). The implications of these varying specificities and sensitivities are as previous- ly noted above for men.
A
B
C
Figure 1. Receiver operating characteristic (ROC) analy- sis curves of red cell values in men with polycythemia vera (PV) versus men with essential thrombocythemia (ETJAK2V617F) (triangle markers) and women with PV versus women with ETJAK2V617F (diamond markers). (A) For hema- tocrit (HCT), (B) for hemoglobin (HGB), and (C) for red blood cells (RBC).
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haematologica | 2019; 104(11)