What should be checked for the newborn's foot blood and when is the best time to collect the foot blood?

A few days after the baby is born, you will need to draw one or two drops of blood from the baby's heel. This is actually to check whether the baby has some diseases, such as phenylketonuria, hypothyroidism, etc. So what diseases can be checked by the newborn's heel blood?

What to check for in the newborn's foot blood

Currently, heel blood tests in my country mainly check for phenylketonuria, hypothyroidism, congenital adrenal hyperplasia and glucose-6-phosphate dehydrogenase deficiency.

Congenital hypothyroidism (hypothyroidism) can cause mental retardation, short stature, etc. if not discovered in time, and it is irreversible. However, if it is discovered in time and given thyroid hormone replacement therapy, more than 95% of cases can be treated and maintain a normal life.

Phenylketonuria Phenylketonuria (PKU) is an autosomal recessive genetic disease. It is named because of the disorder of phenylalanine metabolism in babies, and a large amount of metabolites such as phenylpyruvic acid are excreted in the urine. Phenylalanine is one of the essential amino acids for the human body. After being ingested by food, part of it is used by the body for protein synthesis, and the rest is converted into other substances. Phenylalanine in the baby's body cannot be metabolized normally, but accumulates in the body, causing damage to the central nervous system and a series of pathological changes. Disease signs The baby will gradually have abnormalities in the nervous system such as hair turning from black to yellow, skin turning white, and iris turning lighter, increased muscle tension, abnormal gait, slight tremor in the hands, and repetitive limb movements. It is particularly worth noting that the baby's urine has a very unpleasant smell of mouse urine. In addition, the baby is also prone to eczema, vomiting, diarrhea, etc. In treatment, a low-phenylalanine diet is used to ensure the supply of various nutrients needed for the baby's normal growth and development, and to avoid excessive intake of phenylalanine. Once diagnosed, treatment should be given immediately. The earlier the treatment, the better the prognosis.

Congenital adrenal hyperplasia is an autosomal recessive genetic disease. Female infants present with genital hermaphroditism, while male infants present with pseudo-precocious puberty. The incidence rate in my country is 1:5000-15,000.

Glucose-6-phosphate dehydrogenase deficiency is a common X-linked incomplete dominant genetic and metabolic disease with a higher incidence in male infants. The clinical manifestations are acute hemolytic anemia and hyperbilirubinemia.

When is the best time to draw blood from the sole of your foot?

Blood can be drawn from the baby's foot 72 hours after birth. According to the requirements, blood can be drawn from the baby's foot after the baby is born has been fed 8 times, regardless of whether it is breast milk or formula milk. This is not a hard requirement.

It should be noted that the baby is full when the baby eats more than 8 times, so that the screening result is more accurate. The foot blood is collected half an hour after feeding. Before blood collection, you can warm and massage the baby's feet to promote blood circulation. Blood is easily shed during blood collection to prevent the baby from feeling uncomfortable due to squeezing.

Is it necessary to draw blood from the heel?

A heel prick is the least harmful to the baby.

First, babies have abundant capillaries in their feet. Second, babies also feel pain when drawing blood from their heels, but the pain in the feet is not obvious compared to other parts of the body, and it can minimize the pain of babies. Finally, we don’t draw blood from babies’ fingers because newborns’ hands are usually clenched, and forcibly stretching them out is not conducive to operation.