Objective: To evaluate the efficacy and efficiency of newborn screening for classic congenital adrenal hyperplasia (CAH) in New Zealand.
Design: All infants younger than 6 weeks of age identified by newborn screening between December 1984 and December 1993 were included.
Results: 23 cases of classic CAH (20 salt-losers) were identified. The incidence of classic CAH was 1 in 23,344. Screening identified 3 of 9 virilized female infants whose disease had not been detected clinically. Screening alone identified all 11 male infants. Notification of cases occurred at 11 +/- 3 days of age. There was a delay in treatment of the group identified by screening alone (n = 14) until 13 days of age (range, 4 to 35 days); at that time 11 infants had hyponatremia and 10 had hyperkalemia. Symptoms of vomiting, poor feeding, and shock were common after 10 days of age (2/10, < 10 days, and 8/8, 11 to 16 days of age).
Conclusions: Newborn CAH screening is the only method of identifying male infants with classic CAH without a family history of CAH before symptoms develop, as well as a significant portion of overlooked virilized female infants. So that clinical or significant biochemical deterioration can be avoided, pediatrician notification of screening results and treatment should be started before 10 days of age.