In the Commonwealth of Virginia, 299,420 newborns were screened for biotinidase deficiency and galactosemia during the years 1989-1991 using enzymatic assays for galactose-l-phosphate uridyl transferase activity and biotinidase activity on dried blood filter paper cards. Retrospectively, false-positive initial samples for galactosemia or biotinidase deficiency were identified, and monthly frequencies of false-positive results were determined. The false-positive rates for galactosemia and biotinidase deficiency screening decreased over the 3-year period and were significantly higher in galactosemia screening for each year examined P < 0.001). For galactosemia screening, monthly false-positive rates were highest during May through September, seasonal differences in false-positive rates were significant for each year evaluated (P < 0.001). and seasonal false-positive rates for the 3 years combined were highest during the summer and lowest during the winter. For biotinidase deficiency, differences in seasonal false-positive rates were significant in 1989 (P<0.001) and 1991 (P<0.01), and the highest seasonal false-positive rate for the 3 years combined occurred in the spring. Average monthly temperature and year of measurement were significant factors in galactosemia screening only (P< 0.0001) and accounted for much of the variance in false-positive rates (r2 = 0.43). Approximately half of the infants with false-positive results for biotinidase deficiency were premature, significantly more than the incidence of prematurity in Virginia (7-8%) during the 3 years (P<0.001). Prematurity in false-positive galactosemia screens was not significantly different from expected rates.
- Biotinidase deficiency
- Enzyme test
- Newborn screening
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health