Initial Screening for PKU Performed on Newborns Before Their Discharge

Multiple Choice

Initial screening for PKU performed on newborns before their discharge from the hospital uses a blood sample rather than a urine sample because:

A) Urine samples are more difficult to collect
B) Serum bilirubin levels are routinely measured on all newborns
C) It is easier to measure phenylalanine than phenylpyruvic acid
D) Increased serum phenylalanine can be detected earlier