Which condition is NOT detected by universal pulse oximetry screening?

Universal pulse oximetry screening is a valuable tool used to identify critical congenital heart defects by measuring the oxygen saturation levels in a newborn's blood. It is particularly effective for conditions that result in significant blood flow abnormalities or cyanosis.

Ventilation-perfusion mismatch, on the other hand, refers to a situation where the air that reaches the alveoli (ventilation) does not match with the blood flow in the pulmonary capillaries (perfusion). This condition can arise in various respiratory diseases but is not typically caused by congenital heart defects and does not directly affect blood oxygen levels in a way that pulse oximetry could evaluate effectively.

Conditions like coarctation of the aorta, transposition of the great arteries, and hypoplastic left heart syndrome are primarily characterized by significant circulatory disturbances that lead to differences in oxygen saturation. Thus, they are detectable through universal pulse oximetry screening, making the choice addressing ventilation-perfusion mismatch the option that is not detected by this screening method. This highlights the specific focus of pulse oximetry on circulatory issues rather than broader respiratory or ventilation-related problems.