The aim of this study was to compare values arterial blood gas values obtained by laboratory technical reference with values obtained by the i-STAT® CG8+ analyzer, in order to confirm their validity and thus extrapolate its applicability in academic research in the context of physical activity. Were collected 22 samples of blood from the radial artery of the non-dominant arm of patients admitted to the ITU of the Hospital São João Batista, located in Viçosa, Minas Gerais, in the period from February to March 2013. Were compared between the reference method Ciba Corning Gas System 278 and i-STAT® CG8+ portable analyzer the result of the following variables: pH; PO2 and PCO2 expressed in mmHg; HCO3, and TCO2 BE (base excess) expressed in mmol / L; sO2 and expressed as a percentage of saturation. The student t test, correlation test, and Bland-Altman analysis were used. For all blood parameters monitored in the comparison of mean values between the two methods, no significant difference was found for any of the variables. There was a significant correlation (p<0.0001) and strong, with all correlation coefficients (r) above 0.93, between the two methods for all variables. The Bland-Altman analysis showed that there was agreement between the two methods, with over 90% of the sample between the limits of agreement for all variables. The i-STAT® CG8+ analyzer presented acceptable validity in the resting situation by reference to the Ciba Corning 278 Gas System device, and its use is an excellent strategy for research in the area of sport and health sciences that require fast results in the resting situation and that ensure the effectiveness of decision making.