It was with great interest that we read the review dedicated to pulse oximetry that was published in August issue of CHEST.1This review nicely highlights the benefits and limitations of such a recording tool in the screening of patients suspected of having sleep apnea syndrome. We agree with the authors that the utility of such a simple recording in our investigation strategy definitively needs to addressed in this time when the referrals for sleep and breathing investigation are rapidly increasing. We were quite surprised to find out that the literature detailed in this review did not mention and discuss the results that we published in 1993 on the utility of home oximetry in a large sample of outpatients.2This study was the first to evaluate a new interpretation procedure for oximetry tracings that looked at the desaturation/resaturation pattern without considering any threshold for arterial oxygen saturation (Sao2) fall or minimal Sao2 amplitude to be reached. This was justified by the inability of the test to confirm the diagnosis in a subset of sleep apnea patients when the interpretation is based on rigid criteria defining Sao2 decline.3 In these circumstances, the sensitivity of home oximetry in pioneer studies such as the one of Williams et al3 may be lower than the one reported in the review by Netzer et al1(65% instead of 78%). Following the publication of our results2 and the recognition of their importance in clinical practice,4the interpretation algorithm of subsequent studies evaluating the diagnosis value of oximetry was based on Sao2 variability analysis.5 In complement to the interpretation of the results of the literature detailed by Netzer et al,1 it should be mentioned that the poor specificity that we and others6observed with this screening method dramatically depends on the definitions used to define breathing abnormalities and especially hypopneas. In fact, most of the articles cited in this review considered a minimal Sao2 fall as an obligatory event associated with flow reduction to consider the presence of an hypopnea. However, according to the recommendations of up-to-date guidelines,7 such Sao2 changes are no longer required to score such breathing abnormality. At the end of the spectrum, nonapneic, nonhypopneic events (respiratory effort-related arousals) can be observed in the absence of significant nocturnal desaturation. It is clear that if our data were reanalyzed with these new criteria, the specificity would be dramatically enhanced with a minor alteration of the sensitivity of our method. In this context, we believe that the analysis of Sao2 variability alone is more than ever of first importance in the interpretation of oximetry tracings. Prospective studies that will take into account for these new definitions of sleep-related breathing disorders need to be conducted to evaluate the accuracy of overnight oximetry in the diagnosis of the disease.