What is newborn screening?

Newborn screening involves laboratory testing of all newborn infants for certain genetic/metabolic or endocrine disorders of body chemistry. In addition to laboratory capabilities, necessary components of a successful newborn screening program include tracking and referral of at-risk infants until further diagnostic testing is performed and long-term follow-up of children diagnosed with a disorder.

These tests should be considered screening tests only. Screening can indicate the possibility that an infant may be at risk for a disorder included in the testing panel. Additional diagnostic tests are necessary to determine if the infant with an abnormal test actually has a disorder.

What are the limitations?

Not all affected infants may be identified through screening. The accuracy of screening tests depends on various factors, including the way the specimen is collected, infant’s age at testing, birth weight, gestational age, feeding type, transfusion status, medications and the presence of co-existing illness or medical conditions. If the infant with normal screening test results has symptoms of a disorder or medical problems associated with metabolic disorders, further diagnostic tests may be necessary regardless of the baby’s newborn screening results. While newborn screening has proven to be reliable in the early detection of some metabolic, endocrine and hemoglobin disorders, as with any laboratory tests, false positive and false negative results are possible.

What is tandem mass spectrometry newborn screening?

In addition to providing screening for the six legacy newborn screening disorders (biotinidase deficiency, congenital adrenal hyperplasia, congenital hypothyroidism, galactosemia, phenylketonuria and sickle cell disease and other hemoglobinopathies), on July 1, 2002, the Illinois Department of Public Health (IDPH) Division of Laboratories implemented an additional laboratory technology for screening the dried blood filter paper specimens collected from newborn infants. This technology, tandem mass spectrometry or MS/MS, utilizes special instruments to analyze the dried blood spot specimens for specific metabolites that are produced during the metabolism of proteins and fats. MS/MS screening is utilized to detect amino acid, organic acid and fatty acid oxidation disorders. This technology supplements, rather than replaces existing laboratory technologies.

What analytes are measured by tandem mass spectrometry?

MS/MS detects abnormal levels of amino acids and acylcarnitines. Abnormal elevations of these amino acids may indicate the newborn is at risk for disorders of amino acid metabolism. Free carnitine is a chemical that acts as a transporter of fatty acids into and out of the mitochondria, and is necessary for normal energy metabolism. Acylcarnitines are fatty acids or organic acids that are bound to carnitine. These acylcarnitines vary in size, based on the number of carbon atoms and the type of chemical bonds within the molecule. Abnormal levels of these acylcarnitines can act as markers for certain organic acid and fatty acid oxidation metabolic disorders.

When will I get MS/MS results?

Abnormal MS/MS results are reported to the physician of record as soon as possible by the Genetics/Newborn Screening Program follow-up staff. The most serious abnormal results are reported by phone, letter and fax; and recommendations for further testing or referral to a metabolic specialist also are provided, along with a list of recommended metabolic specialists and a fact sheet about the suspected disorder. A written report of all normal and abnormal test results for each specimen received also will be sent to the submitting hospital by the Illinois Department of Public Health Division of Laboratories.

What metabolic disorders can be detected by tandem mass spectrometry?

MS/MS enables the Illinois Department of Public Health Division of Laboratories to detect several broad categories of metabolic disorders, including amino acid disorders and several urea cycle disorders, organic acid disorders and fatty acid oxidation disorders. The following is a summary of the disorders that may be detected by tandem mass spectrometry during the newborn period.

What if I have questions?

Illinois Department of Public Health 535 West Jefferson Street Springfield, Illinois 62761 Phone 217-782-4977 Fax 217-782-3987 TTY 800-547-0466 Questions or Comments