Newborn screening is an easy way to screen newborns for genetic metabolic diseases. A few drops of heel blood can be taken from a baby to screen for a variety of genetic metabolic diseases, making it a very economical, efficient and valuable test. Generally, heel blood is taken 3 days after birth for screening. The free screenings included vary slightly from province to province, such as congenital hypothyroidism (CH), phenylketonuria (PKU), congenital adrenocortical hyperplasia (CAH), glucose-6-phosphate dehydrogenase deficiency (G6PD), and in some provinces, primary carnitine deficiency, methylmalonic acidemia, propionic acidemia, histrionic protein deficiency, and more. Some hospitals will also have self-pay screening programs, such as tandem mass spectrometry testing, which can detect nearly 30 disorders, for amino acid, fatty acid and organic acid metabolism disorders, depending on the needs of the parents. In addition, each baby will be screened for hearing, and some hospitals will perform ultrasound screening for congenital hip dysplasia and congenital oblique neck. Newborn disease screening can effectively detect certain genetic metabolic diseases at an early stage, achieve early diagnosis, early treatment, prevent irreversible damage to the body tissues and organs, and prevent the occurrence of mental retardation, serious diseases or death in affected children, avoiding greater trouble for many families.