Which laboratory test is routinely included in the evaluation of metabolic disorders in the newborn period?

Which laboratory test is routinely included in the evaluation of metabolic disorders in the newborn period?

• A. Glycosylated hemoglobin
• B. Urine electrolytes
• C. Serum AST, GGT, ALT
• D. Serum amino acids

Answer: (D)

Measuring amino acids in the newborn blood is routinely done because many inherited metabolic disorders involve amino acid metabolism and produce detectable imbalances before symptoms appear. Modern newborn screening uses tandem mass spectrometry on dried blood spots to assess multiple amino acids (and related metabolites) in one test, enabling early identification of aminoacidopathies such as phenylketonuria and maple syrup urine disease, among others. Early detection allows prompt dietary management and treatment to prevent neurodevelopmental issues. Glycosylated hemoglobin reflects long-term glucose control and isn’t used for newborn metabolic screening. Urine electrolytes are not a standard panel for evaluating metabolic disorders in the newborn, and liver enzyme panels (AST, ALT, GGT) indicate liver injury rather than serving as routine screening for inborn metabolic diseases.

Measuring amino acids in the newborn blood is routinely done because many inherited metabolic disorders involve amino acid metabolism and produce detectable imbalances before symptoms appear. Modern newborn screening uses tandem mass spectrometry on dried blood spots to assess multiple amino acids (and related metabolites) in one test, enabling early identification of aminoacidopathies such as phenylketonuria and maple syrup urine disease, among others. Early detection allows prompt dietary management and treatment to prevent neurodevelopmental issues.

Glycosylated hemoglobin reflects long-term glucose control and isn’t used for newborn metabolic screening. Urine electrolytes are not a standard panel for evaluating metabolic disorders in the newborn, and liver enzyme panels (AST, ALT, GGT) indicate liver injury rather than serving as routine screening for inborn metabolic diseases.