摘要： Critical congenital heart defects can lead to serious morbidity and mortality if not found at the appropriate time. Although prenatal ultrasound and postnatal neonatal physical examination can detect the majority of severe congenital heart disease, more than 20% of newborns are still not diagnosed before discharge from the birth hospital. The diagnosis of critical congenital heart defects using pulse oximetry can reduce these diagnostic problems, and it is necessary to consider introducing it as a neonatal screening test in Korea. However, as the prevalence rate of disease and the medical system vary from country to country, it is necessary to study whether this screening test is effective or cost effective in our country. Newborns with a positive result that did not pass a critical congenital heart defects screening using pulse oximetry would require thorough follow-up testing to identify not only severe congenital heart disease but also other potential causes of hypoxia. However, even if the neonate has passed the critical congenital heart defects screening test using pulse oximetry, this screening test has a low sensitivity and a high false positive rate, so it cannot be a perfect screening test for critical congenital heart defects. Therefore, when this screening test is performed at each hospital, it is important to educate and follow the caregivers of signs and symptoms of other congenital heart diseases other than hypoxemia.