Plantar blood tests are performed to screen newborns for inherited metabolic disorders such as congenital hypothyroidism and phenylketonuria, as well as to screen newborns for the gene for deafness. Plantar blood test is the collection of newborn’s plantar blood to screen for certain neonatal inherited metabolic diseases. Among the inherited metabolic diseases, the most common ones are congenital hypothyroidism, phenylketonuria, glucose 6 phosphate dehydrogenase deficiency, etc. Rarely, there are amino acid metabolism diseases, such as maple diabetes mellitus, histidine metabolism disease, organic acid metabolism diseases, such as malonucleic acidemia, isovaleric acidemia, etc., fatty acid oxidation defective diseases, such as primary weak base deficiency, etc.. Plantar blood tests can also screen for newborn deafness genes and assess a baby’s risk for diseases that cause hearing impairment. These neonatal inherited metabolic diseases do not have obvious symptoms in the early stage, but positive laboratory indicators found through the plantar blood test can be detected, diagnosed, and intervened in the neonatal period for early treatment in order to avoid serious harm to the baby. Plantar blood collection is usually performed within 72 hours to 7 days of the birth of a newborn. After the birth of a newborn, it is recommended to visit the hospital in a timely manner and make an appointment for plantar blood collection screening under the guidance of a physician.