Lambert LL, et al. - In this retrospective review, researchers analyzed subjects' records to investigate how accurately transcutaneous carbon dioxide (P_tcCO2) values correlated with CO₂ values obtained by arterial blood gas (ABG) or capillary blood gas. They obtained information regarding P_tcCO2 value at the time of blood gas procurement and the ABG or capillary blood gas PCO₂ value. According to findings, less variation was shown by capillary blood gas comparisons. They also found that relative to ABG comparisons, a slightly lower correlation with P_tcCO2 was demonstrated by capillary blood gas comparisons. The wide limits of agreement and poor repeatability were shown to account for the questionable utility of relying on P_tcCO2 readings for this purpose, after accounting for serial measurements per patient.