There are 25 national and regional screening programs for CAH worldwide. Critical factors which have influenced widespread acceptance of CAH screening include timely therapeutic intervention and the high false positive rate. Early neonatal discharge may have a negative impact on CAH screening. We analysed the first 6 years of data generated by CAH screening in Manitoba. Between 1989-1994 105,728 newborns were screened for CAH. One male was identified by screening and one female was identified in utero by amniocentesis. The calculated prevalence of CAH is 1:52,864 (95% confidence limits 1:90,007-1:14,721) compared to the previous 20 years clinical prevalence of 1:14,500 in Manitoba. The false positive rate for immediate referrals was 0.11% and the false positive rate for marginally elevated levels was 1.4% (17-hydroxyprogesterone (17OHP) cutoff levels of 70 and 40 nmol/L respectively). The cost of CAH screening was US $3.18 per reported result(labor and supplies). A 9 month period was used to evaluate the impact of early discharge on CAH screening in 11,424 newborns. The 17OHP levels increased when the age at sampling decreased (p<0.0001). The frequency of false positive and intermediate values was affected by the age at sampling in the same direction, particularly for infants >2.5 kg. Overall 5.27% of the infants required a second sample when they were sampled at <48 hr versus 2.07% at >48 hrs. With the current rate of early discharge (<48 hrs) of 11.45%, the increase in the cost of screening is minimal but future trends must be evaluated. The cost of CAH screening can only be compared to the cost of hospitalization for adrenal crisis, loss of life and life long productivity. Continued evaluation of the programme in Manitoba will be necessary in view of the apparent low prevalence of CAH.Table

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