What is being tested with the heel prick screening test, and why?

In the first week after birth, a few drops of blood are taken from your baby's heel. The blood is tested for several serious, rare congenital diseases. These can usually not be cured but can be treated, for example, with medicines or a diet. Treatment can also start quickly if a condition is detected soon after birth. This can prevent severe damage to your child's physical and mental development.