The phenylketonuria (PKU) sampling service involves collecting a blood sample to test for the presence of elevated levels of phenylalanine in the body. PKU is a genetic metabolic disorder in which the body cannot properly break down phenylalanine, an amino acid found in proteins and foods, leading to elevated levels of this compound in the blood.

Sampling is done by drawing a small amount of blood from the patient, usually from the arm, using a sterile needle and a specialized sample collection tube. This sample is sent to a clinical laboratory for analysis.

PKU testing is primarily done as part of newborn screening, an exam performed shortly after the baby is born to detect certain metabolic disorders, including phenylketonuria. This test seeks to measure the levels of phenylalanine in the newborn's blood.

Early detection of PKU is crucial, as elevated levels of phenylalanine can cause brain damage if left untreated. If PKU is detected, early interventions can be implemented, usually dietary changes to limit phenylalanine intake, which can prevent the development of health problems related to this condition.

In summary, sampling for PKU involves drawing blood to measure phenylalanine levels and is typically performed as part of newborn screening to detect and treat PKU early.