Nailfold capillaroscopy is a simple method for determining microvascular damage in systemic sclerosis (SSc). The pulse oximeter is a noninvasive tool that is used to estimate a patient's arterial blood oxygen saturation. The aim of this study was to investigate the effect of capillaroscopic patterns on pulse oximetry measurements in SSc patients. The nailfolds from 2nd to 5th fingers in both hands were examined in all subjects by using capillaroscopy. Patients were categorized according to their capillaroscopy findings in 3 groups as having early, active or late patterns. Oxygen saturation (SpO(2)) measurements were performed from 2nd to 5th fingers in both hands with a finger probe. We studied 53 SSc patients (F/M: 48/5). According to capillaroscopy findings 18 patients were classified as having early pattern (34.0%), 19 active pattern (35.8%), and 15 late pattern (28.3%). Only 1 (1.9%) patient had normal capillaroscopy findings. SpO(2) could not be measured in 47 (11.0%) fingers and in 20 (37.7%) SSc patients. There were 20 (37.7%) patients with >= 4% a difference between the minimum and maximum SpO(2) measurements among fingers. There were no difference between the groups of SSc patients defined by capillaroscopy findings in terms of mean maximal SpO(2) or mean minimal SpO(2) measured from fingers (p NS, for all). Assessment of SpO(2) values in patients with SSc is challenging. We did not detect any effect of capillaroscopic patterns on mean SpO(2) values. On the other hand.LI% difference between minimum and maximum SpO(2) values measured from fingers of a patient may be considered as an indirect sign of microvascular damage. Assessment of the highest measured SpO(2) values among the fingers of a patient may be more suitable in practice. (C) 2014 Elsevier Inc. All rights reserved.