Why is metabolic screening important, the heel test that detects over 20 treatable diseases from the first days of life
The metabolic test is done in the first 24-30 days of life, ideal in the first 48-72 hours. After one -month age, chemical markers may normalize or mask, and analysis loses precision/photo: shutterstock
A newborn may seem perfectly healthy at discharge, but an unseen metabolic defect can endanger his growth from the first weeks. The new neonatal screening extended with tandem-meass spectrometry (MS/MS) discovers more than 20 errors in accordance with metabolism before the symptoms appear and gives the child the chance to a normal life.
The classic heel test (Guthrie), launched in the 1960s and which is done to all babies in maternity, detects phenylcetonuria (PUK), urine disease with maple smell (MSUD), galactosemia, hypothyroidism. A single drop of blood was harvested from the newborn's heel. The introduction of tandem-meass-Spectrometry (MS/MS) in the early 1990s-through which, on the same blood disk can be “chemically read” in a few minutes dozens of metabolites-has changed how newborns with metabolic diseases live.
Why is the extended metabolic screening important
The importance of this test is that it allows the diagnosis of over 20 congenital metabolism diseases since the neonatal period. In this way, the proper treatment can be started early, avoiding the onset of complications caused by these diseases.
“All congenital metabolism diseases are lethal, in the absence of proper treatment. If the metabolism does not work in normal parameters, an imbalance occurs and in terms of the coherent functioning of the organs and thus, permanent lesions, from mental retardation, appear,” explains the pediatric doctor Cristian Minulescu.
How to harvest and when the answer arrives
The procedure is the same sting in heels that newborns already received. The nurse gently warms the foot, cleanses with alcohol, stings on the side and leaves three to four drops of blood to impregnate the cardboard circles. The difference appears after drying. The sample is inserted into an envelope with a unique bar code and starts, under a custody chain, to the Laboratory Acredited ISO 15189, where it enters the MS/MS analyzer. The technology ionizes the molecules and identifies the signature of each metabolite after mass/electric charging – a “chemical bar code”.
The result comes in a color code: green (negative), yellow (need for retest), red (positive). In parallel, an automatic SMS announces the availability of the result, and the counseling service sounds the parents if a red marker appears, to program immediately to the pediatric metabolist. Thus, the family never remains alone in front of a page with heavy medical terms.
Who and when should they do extended metabolic screening?
Who does the test: Any healthy baby at first sight, immediately after birth. Even if parents do not have medical problems, “hidden” genes can be transmitted that cause rare metabolic disorders-which is why the test is recommended to all newborns without symptoms. Children who already have suggestive signs for a metabolic disease enter a separate diagnostic route, not in the routine screening program.
Optimal interval: The first 24-30 days of life, ideal in the first 48-72 hours. After one month, chemical markers can be normalized or mask, and the analysis loses precision.
After the result: An “alarm signal” at screening is not a final verdict. There are confirmation tests specific to each disease – additional blood tests, enzymatic tests or genetic investigations – before the doctor makes a certain diagnosis.
Why is it worth: Early detection allows the rapid initiation of the special diet, enzymatic supplements or other therapies that can keep the disease under control. With early treatment, most children with metabolism errors have real chances of growing and developing as their peers.
What happens if the test comes out positive
If a red mark appears on the report, it does not represent a definitive verdict, but only a suspicion that the pediatricians with competence in hereditary diseases of metabolism explores methodically. The first step is the recall of the child: the harvest is repeated, and sometimes an additional genetic test is performed to eliminate the risk of contamination or the influence of maternal nutrition – as is the case, for example, when the mother takes high doses of biotin.
If the second sample raises alarm signs, the newborn stays 24-48 hours in a neonatal intensive care section, where doctors monitor ammonia, lactate and glucose and administer dextrose infusions to stop the degradation of proteins in the body. After confirmation, it goes to the targeted treatment: dietary regimes that eliminate toxic amino acid (for example, leucine restriction, in the “urine disease with maple smell”), carnitine supplements and specific vitamins or, in critical situations, hemodialysis.
Studies show that many of the disorders discovered in time allow normal neuropsychic development when therapy begins before the first metabolic crisis. In just a few drops of blood and a few days of waiting, the extended metabolic screening gives the most important parent: the certainty that it did everything for his little one to start in life with the biochemical engines regulated from the beginning.
