Aims: This study aims primarily to assess the extent of the collateral circulation of the hand in a combined population of healthy individuals and patients who underwent transradial catheterisation, using both the Nexfin system and laser Doppler perfusion imaging. Methods and results: In total, 85 adults were included in the study (18 healthy volunteers; 67 patients who underwent transradial catheterisation). The perfusion of the thumb was assessed prior to and during complete radial artery compression using laser Doppler perfusion imaging (LDPI) and the Nexfin system. The palmar collateral flow index (PCFI) was compared between both devices and PCFINEXFIN was related to hand angiography and the upper limb function, using the QuickDASH questionnaire. Mean PCFILDPI was 0.77±0.15 and mean PCFINEXFIN was 0.88±0.08. Both were significantly related (Pearson correlation=0.49, 95% CI: 0.31-0.64, p<0.001, agreement-0.11±0.13). PCFINEXFIN correlated with the maximal diameter of the superficial palmar arch (R=0.49, p=0.04) and total minimal arch diameter (R=0.51, p<0.02). High PCFINEXFIN, measured at baseline, was correlated with a lower QuickDASH score for pain, activity and total at one month post transradial catheterisation (p=0.02, p<0.01, p<0.01), but not with discomfort or disability. Conclusions: The Nexfin monitoring system is comparable with laser Doppler perfusion imaging in the quantification of the collateral perfusion in the hand. In patients, the Nexfin-derived collateral flow index measured at baseline is associated with clinical outcome at 30 days post transradial catheterisation.