ROC analysis of the calculated slope and RBC capillary velocity in classifying ME/CFS. (A) ROC curves of the calculated slope and RBC capillary velocity (at 0 mm Hg) showed AUC values of 0.82 and 0.62, respectively. (B) Capillary velocity of RBCs from M ME/CFS were higher than that from M/S participants with ME/CFS. ∗∗∗P < .001; ∗∗∗∗P < .0001 (Mann-Whitney test). Calculated slope showed no significant difference between the M and M/S groups. ns, P > .05 (Mann-Whitney test; for M, n = 12; for M/S, n = 16). ROC AUC values for calculated slope and RBC capillary velocity (at 0 mm Hg) are 0.52 and 0.66, respectively.