Neonatal heel prick
Encyclopedia
The neonatal heel prick is a common procedure for taking a blood sample from the heel of newborn infant
s. A pinprick puncture is made in the heel of the infant's foot, and blood from the foot is soaked into pre-printed collection cards known as Guthrie cards.
The blood samples can be used for a variety of genetic tests
, including:
Other potential tests include:
It is recommended that the screening test be performed when the infant is between 48 and 72 hours of age. False positives and negatives can sometimes occur when the screening tests are performed before 48 hours.
With genetic tests becoming more common, a wide variety of tests may use the blood drawn by this method. Many neonatal units (SCBUs) now use this method to carry out the daily blood tests (blood count, electrolytes) required to check the progress of ill neonates.
In the UK, the NHS
test for:
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...
s. A pinprick puncture is made in the heel of the infant's foot, and blood from the foot is soaked into pre-printed collection cards known as Guthrie cards.
The blood samples can be used for a variety of genetic tests
Genetic testing
Genetic testing is among the newest and most sophisticated of techniques used to test for genetic disorders which involves direct examination of the DNA molecule itself. Other genetic tests include biochemical tests for such gene products as enzymes and other proteins and for microscopic...
, including:
- Thyroid stimulating hormone (TSH) to detect hypothyroidismHypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
and hence prevent cretinismCretinismCretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones usually due to maternal hypothyroidism.-Etymology and use of cretin:...
. - TrypsinTrypsinTrypsin is a serine protease found in the digestive system of many vertebrates, where it hydrolyses proteins. Trypsin is produced in the pancreas as the inactive proenzyme trypsinogen. Trypsin cleaves peptide chains mainly at the carboxyl side of the amino acids lysine or arginine, except when...
to detect cystic fibrosisCystic fibrosisCystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
. - Detection of phenylketonuriaPhenylketonuriaPhenylketonuria is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase , rendering it nonfunctional. This enzyme is necessary to metabolize the amino acid phenylalanine to the amino acid tyrosine...
, an enzyme deficiency that can impair brain development.
Other potential tests include:
- A test for galactosemiaGalactosemiaGalactosemia is a rare genetic metabolic disorder that affects an individual's ability to metabolize the sugar galactose properly. Although the sugar lactose can metabolize to galactose, galactosemia is not related to and should not be confused with lactose intolerance...
It is recommended that the screening test be performed when the infant is between 48 and 72 hours of age. False positives and negatives can sometimes occur when the screening tests are performed before 48 hours.
With genetic tests becoming more common, a wide variety of tests may use the blood drawn by this method. Many neonatal units (SCBUs) now use this method to carry out the daily blood tests (blood count, electrolytes) required to check the progress of ill neonates.
In the UK, the NHS
National Health Service
The National Health Service is the shared name of three of the four publicly funded healthcare systems in the United Kingdom. They provide a comprehensive range of health services, the vast majority of which are free at the point of use to residents of the United Kingdom...
test for:
- HypothyroidismHypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
- Cystic fibrosisCystic fibrosisCystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
- PhenylketonuriaPhenylketonuriaPhenylketonuria is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase , rendering it nonfunctional. This enzyme is necessary to metabolize the amino acid phenylalanine to the amino acid tyrosine...
(PKU) - Medium-chain acyl-coenzyme A dehydrogenase deficiencyMedium-chain acyl-coenzyme A dehydrogenase deficiencyMedium-chain acyl-coenzyme A dehydrogenase deficiency is a fatty acid oxidation disorder associated with inborn errors of metabolism. It is due to defects in the enzyme complex known as medium-chain acyl dehydrogenase and reduced activity of this complex...
(MCADD) - Sickle-cell diseaseSickle-cell diseaseSickle-cell disease , or sickle-cell anaemia or drepanocytosis, is an autosomal recessive genetic blood disorder with overdominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various...