Why are dried blood spots used in newborn metabolic screening?

Dried blood spots are used in newborn metabolic screening as a practical and effective method for the early detection of inborn errors of metabolism. This process typically involves collecting a small droplet of blood from a newborn's heel onto an absorbent paper card.12

The use of dried blood spots is significant for several reasons:

• Early Intervention: Many metabolic disorders, such as phenylketonuria, can cause severe illness or brain damage if left untreated. Early diagnosis through screening allows for the immediate implementation of specialized diets or therapies, which can significantly improve an infant's prognosis.32
• Efficiency and Technology: Metabolites extracted from these cards can be screened using mass spectrometry. Modern techniques like tandem mass spectrometry allow for the simultaneous detection of multiple abnormal metabolites, enabling a single blood sample to be used to test for dozens of different conditions.13
• Practicality: The method is minimally invasive and highly scalable, making it a cost-effective way to screen large populations of newborns for rare but treatable genetic defects.41