Fig. 4

ROC curves of LDF-Plantar-Qb for PAD (adjusted for C-reactive protein, creatinine, total cholesterol). Sensitivity, 0.88; specificity, 0.78; cut-off, 20.0 mL/min using Youden’s index method (Additional file 2: Table S4). PAD(−). without peripheral arterial disease; PAD(+) with peripheral arterial disease; SPP, skin perfusion pressure; LDF, Laser Doppler flowmetry; LDF-Dorsal-Qb, LDF blood flow rate in the dorsal area of the foot; LDF-Plantar-Qb, LDF blood flow rate in the plantar area of the foot; LDF-Qb, LDF blood flow rate; SPP-Dorsal Area, skin perfusion pressure in the dorsal area of the foot; ROC, receiver-operating characteristic