Objective: To determine the biochemical screening rate of newborns in South Australia and the factors associated with babies not being screened.
Design: Matching of data in the SA Newborn Screening Centre database (acquired from Guthrie cards) with the SA perinatal data collection (compiled from supplementary birth records) to determine how many newborns missed screening. Risk factors for missed screening were identified from sociodemographic and clinical variables recorded in the perinatal data collection and analysed by multivariable unconditional logistic regression analysis.
Patients and setting: All live births (n = 18,426) in South Australia in 1999, in the 63 hospitals assisting deliveries or in the home.
Main outcome measures: Rates of biochemical screening and missed screening in all newborns and among various subgroups; adjusted odds ratios (after multivariable logistic regression analysis) for risk factors for missed screening.
Results: The newborn screening rate in South Australia in 1999 was 97.8%. Babies born at home, born to an Aboriginal mother, or born to a mother who normally resided in another state were at higher risk of missed screening. Other factors associated with missed screening were having fewer than seven antenatal visits, prematurity (gestational age at birth < 32 weeks), congenital abnormality in the baby, use of paediatric intensive care, early discharge from hospital before 3 days (but especially after less than 1 day), and death of the baby during the neonatal period.
Conclusion: In South Australia, while 2.2% of all newborns missed screening in 1999, in certain high-risk groups the proportions of unscreened babies were significantly higher. With a 2% missed screening rate, one might expect one newborn with a screening-detectable disorder to elude detection every other year in South Australia.