Thangaratinam et al1 should be complimented on the well-conducted systematic review on the accuracy of pulse oximetry in screening for congenital heart disease (CHD) in asymptomatic neonates. It needs to be stressed that more than 60% of CHD is actually non-cyanotic, and pulse oximetry would offer little if any assistance in its detection. Clinical detection of cyanosis is highly clinician dependent, and mild cyanosis is likely to be missed by the relatively inexperienced. Routine pulse oximetry would certainly avoid this risk. Indeed low oxygen …