Based on continuous quality improvement by retrospectively looking at levels of analytes detected in infants referred for screened conditions who had the disease and those who did not, the Newborn Screening Program is making the following modifications:
1. Changing the reference range values for free carnitine (C0) and propionylcarnitine (C3) used for the evaluation of carnitine uptake disorder (CUD)
2. Discontinuing the use of methylmalonylcarnitine (C4DC) as a diagnostic marker for the evaluation of propionic acidemia and methylmalonic acidemia (PA/MMA)