The neonatal heel prick is a blood collection procedure done on

newborn In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to Juvenile (orga ...

s. It consists of making a pinprick puncture in one

heel The heel is the prominence at the posterior end of the foot. It is based on the projection of one bone, the calcaneus or heel bone, behind the articulation of the bones of the lower leg. Structure To distribute the compressive forces exerted ...

of the newborn to collect their

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

. This

technique Technique or techniques may refer to: Music * The Techniques, a Jamaican rocksteady vocal group of the 1960s * Technique (band), a British female synth pop band in the 1990s * ''Technique'' (album), by New Order, 1989 * ''Techniques'' (album), by ...

is used frequently as the main way to collect blood from neonates. Other techniques include

venous Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal c ...

arterial An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

needle sticks, cord blood sampling, or umbilical line collection. This technique is often utilized for the Guthrie test, where it is used to soak the blood into pre-printed collection cards known as Guthrie cards. The classical Guthrie test is named after Robert Guthrie, an American

bacteriologist A bacteriologist is a microbiologist, or similarly trained professional, in bacteriology— a subdivision of microbiology that studies bacteria, typically Pathogenic bacteria, pathogenic ones. Bacteriologists are interested in studying and learnin ...

and

physician A physician, medical practitioner (British English), medical doctor, or simply doctor is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through the Medical education, study, Med ...

who devised it in 1962. The test has been widely used throughout

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and

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

as one of the core newborn screening tests since the late 1960s. The test was initially a bacterial inhibition assay, but is gradually being replaced in many areas by newer techniques such as

tandem mass spectrometry Tandem mass spectrometry, also known as MS/MS or MS2, is a technique in instrumental analysis where two or more stages of analysis using one or more mass analyzer are performed with an additional reaction step in between these analyses to increa ...

that can detect a wider variety of congenital diseases.

Detected diseases

The blood samples can be used for a variety of metabolic tests to detect

genetic condition A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders are ...

s, including: *

Immunoreactive trypsinogen Measurement of immunoreactive trypsinogen (IRT) in blood of newborn babies is an assay in rapidly increasing use as a screening test for cystic fibrosis Cystic fibrosis (CF) is a genetic disorder inherited in an autosomal recessive manner that ...

to detect

cystic fibrosis Cystic fibrosis (CF) is a genetic disorder inherited in an autosomal recessive manner that impairs the normal clearance of Sputum, mucus from the lungs, which facilitates the colonization and infection of the lungs by bacteria, notably ''Staphy ...

. *

Maple syrup urine disease Maple syrup urine disease (MSUD) is a rare, inherited metabolic disorder that affects the body's ability to metabolize amino acids due to a deficiency in the activity of the branched-chain alpha-ketoacid dehydrogenase (BCKAD) complex. It parti ...

(MSUD or Branched Chain Ketonuria) a rare disorder where an error in

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

inhibits the breakdown of

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

leucine, isoleucine and valine. It can impair brain development. *

Medium-chain acyl-coenzyme A dehydrogenase deficiency Medium-chain acyl-CoA dehydrogenase deficiency (MCAD deficiency or MCADD) is a disorder of fatty acid oxidation that impairs the body's ability to break down medium-chain fatty acids into acetyl-CoA. The disorder is characterized by hypoglycemia ...

(MCADD) *

Phenylketonuria Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also r ...

, a disorder where an error in

can impair brain development (PKU) *

Sickle-cell disease Sickle cell disease (SCD), also simply called sickle cell, is a group of inherited haemoglobin-related blood disorders. The most common type is known as sickle cell anemia. Sickle cell anemia results in an abnormality in the oxygen-carrying ...

Thyroid stimulating hormone The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans, it is a butterfly-shaped gland located in the neck below the Adam's apple. It consists of two connected lobes. The lower two thirds of the lobes are connected by ...

(TSH) or Thyroxin (T4) to detect

congenital hypothyroidism Congenital hypothyroidism (CH) is thyroid hormone deficiency present at birth. If untreated for several months after birth, severe congenital hypothyroidism can lead to growth failure and permanent intellectual disability. Infants born with co ...

and hence prevent cretinism. *

Isovaleric acidemia Isovaleric acidemia is a rare autosomal recessive metabolic disorder which disrupts or prevents normal metabolism of the branched-chain amino acid leucine. It is a classical type of organic acidemia. Symptoms and signs A characteristic featur ...

(IVA) * Homocystinuria (pyridoxine unresponsive) (HCU) * 17-hydroxy-progesterone (17-OHP) to detect

adrenogenital syndrome Congenital adrenal hyperplasia (CAH) is a group of Genetic disorder#Autosomal recessive, autosomal recessive disorders characterized by impaired cortisol synthesis. It results from the deficiency of one of the five enzymes required for the Biosy ...

, also known as

congenital adrenal hyperplasia Congenital adrenal hyperplasia (CAH) is a group of Genetic disorder#Autosomal recessive, autosomal recessive disorders characterized by impaired cortisol synthesis. It results from the deficiency of one of the five enzymes required for the Biosy ...

Galactosemia Galactosemia (British galactosaemia, from Greek γαλακτόζη + αίμα, meaning galactose + blood, accumulation of galactose in blood) is a rare genetics, genetic Metabolism, metabolic Disease, disorder that affects an individual's ability t ...

Mechanism

The test uses the growth of a strain of bacteria on a specially-prepared agar plate as a sign for the presence of high levels of phenylalanine, phenylpyruvate, and/or phenyllactate. The compound B-2-thienylalanine will inhibit the growth of the bacterium ''Bacillus subtilis'' (ATCC 6051) on minimal culture media. If phenylalanine, phenylpyruvate, and/or phenyllactate is added to the medium, then growth is restored. Such compounds will be present in excess in the blood or urine of patients with PKU. If a suitably-prepared sample of blood or urine is applied to the seeded agar plate, the growth of the bacteria in the test will be a positive indicator for PKU in the patient. To prepare the sample for application, a small amount of blood (from a heel puncture, for example) or urine (from a diaper, for example) is applied to a piece of filter paper. Then a small disc is punched from the center of the spot of blood or urine, and the disc applied to the surface of a seeded, minimal-medium agar plate that contains added beta-2-thienylalanine. If the sample contains phenylalanine, phenylpyruvate, and/or phenyllactate then these compounds will diffuse into the agar medium. If their concentrations are high enough (as with the excess levels seen with PKU), bacteria will grow under the disc, but not elsewhere. Generally an overnight incubation is enough to determine whether phenylalanine, phenylpyruvate, and/or phenyllactate are present in unusual concentrations in blood or urine.

Timing

The blood spot sample should be taken between 48 and 72 hours of age for all babies regardless of medical condition, milk feeding and prematurity. For the purpose of screening, date of birth is day 0 (some IT systems record date of birth as day 1).

False positive A false positive is an error in binary classification in which a test result incorrectly indicates the presence of a condition (such as a disease when the disease is not present), while a false negative is the opposite error, where the test resu ...

s and

false negative A false positive is an error in binary classification in which a test result incorrectly indicates the presence of a condition (such as a disease when the disease is not present), while a false negative is the opposite error, where the test resu ...

s can sometimes occur when the screening tests are performed before 48 hours. When the

immunoassay An immunoassay (IA) is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes). The molecule detected by the immunoassay ...

method is utilized as a screening method for quantifying 17α-hydroxyprogesterone (17OHP) in dried blood spots, it exhibits a significant rate of false positive results. As per the clinical practice guideline issued by the Endocrine Society in 2018, employing LC-MS/MS to measure 17OHP and other adrenal steroid hormones (such as 21-deoxycortisol and androstenedione) is recommended as a supplementary screening approach to enhance the accuracy of positive predictions. 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.

Data retention controversy

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, a

controversy Controversy (, ) is a state of prolonged public dispute or debate, usually concerning a matter of conflicting opinion or point of view. The word was coined from the Latin '' controversia'', as a composite of ''controversus'' – "turned in an op ...

emerged in

2012 2012 was designated as: *International Year of Cooperatives *International Year of Sustainable Energy for All Events January *January 4 – The Cicada 3301 internet hunt begins. * January 12 – Peaceful protests begin in the R ...

whereby a number of

hospital A hospital is a healthcare institution providing patient treatment with specialized Medical Science, health science and auxiliary healthcare staff and medical equipment. The best-known type of hospital is the general hospital, which typically ...

s retained heel prick test cards and thereby a DNA database with over a million samples from

1984 Events January * January 1 – The Bornean Sultanate of Brunei gains full independence from the United Kingdom, having become a British protectorate in 1888. * January 7 – Brunei becomes the sixth member of the Association of Southeas ...

, without

consent Consent occurs when one person voluntarily agrees to the proposal or desires of another. It is a term of common speech, with specific definitions used in such fields as the law, medicine, research, and sexual consent. Consent as understood i ...

or notification of parents. This resulted in a ten-year rolling destruction cycle being introduced. Similar practices exist in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

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, and several

states State most commonly refers to: * State (polity), a centralized political organization that regulates law and society within a territory **Sovereign state, a sovereign polity in international law, commonly referred to as a country **Nation state, a ...

of the

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Heel stick wound

Heel stick

wound A wound is any disruption of or damage to living tissue, such as skin, mucous membranes, or organs. Wounds can either be the sudden result of direct trauma (mechanical, thermal, chemical), or can develop slowly over time due to underlying diseas ...

s are a

cutaneous condition A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this sys ...

characterized by a break in the skin caused by neonatal heel prick. The heel stick is an important medical screening for the child and causes low levels of pain.

References

External links

Heel prick test
at the General Practice Notebook {{Tests relating to nutrition Midwifery Neonatology