Wed, 08 Jan 2003

Screening crucial to identify disorders

Donya Betancourt, Pediatrician,

Have you heard about newborn screening? The fact is that today blood screening is a normal part of a newborn child's life cycle.

There are important metabolic and endocrinologic disorders that can occur beginning at birth, and if left untreated these disorders can result in seizures, stunted growth or even death. For this reason, the blood screening of newborns plays an important and helpful role in identifying metabolic and endocrinologic disorders before symptoms ever appear.

Before such tests were available, some babies developed serious health problems, including mental retardation, that were irreversible. Today if these disorders are detected and treated early enough, they can be controlled or may even be successfully treated. Babies who would have developed life-threatening health problems or mental retardation now are able to grow up as healthy children.

The fact is that individually these disorders are quite rare. Depending on the disorder, they might affect one in every 500 newborns or one in every 150,000 newborns. But collectively these disorders are common enough that it is worth the effort to check every baby. With mass screening protocols, treatable disorders are being detected in at least one in every 5,000 newborns.

There are two newborn metabolic screenings which most countries can administer: phenylketonuria (PKU) and hypothyroidism. There are more screenings such as galactosemia or homocystinuria but these are not widely in use at the moment.

The routine is, a day or two after a baby is born a sample of blood is taken from the heel of his or her foot. This is called a heel stick.

The blood is collected, nine or 10 drops on a piece of filter paper, and then sent to the laboratory for analysis. Until recently, as additional disorders have been identified each new test required more blood and increased the cost of testing. Now new laboratory techniques using tandem mass spectrometry have been developed so that one small blood sample can be used to identify 20 to 30 different conditions.

There has been a real improvement in metabolic screening for newborns. But we still don't have this technology in Asia, consequently if the blood test comes back positive for a certain condition the baby will undergo additional testing, which is usually more blood tests and sometimes urine tests.

Follow-up testing is more complex, and the baby might be referred to a specialist in diagnosing and treating the specific condition. If a condition is diagnosed in a baby, the parents will receive counseling and instruction in diet modification and other aspects of treatment.

A practical note for parents is that it is common to have the first routine medical appointment with your baby's primary doctor within a week or so after going taking your baby home from the nursery. This is the perfect time to review the results of newborn metabolic screening. It's a good idea to ask about the newborn screening results if your physician doesn't bring them up, because if any retesting is required it's best to proceed right away.

As I mentioned, blood screening tests require a very small amount of blood and the benefits of early diagnosis and treatment is worth any discomfort the child may experience. So when your child's doctor ask to take a blood test, remind yourself that prevention is always better than treatment.