Newborn mass screening versus selective investigation: benefits and costs.

Cost-benefit analysis of newborn screening has an unimpressive record and yet it is still regarded as an important decision tool. This workshop surveyed ongoing research into the costs and benefits of systematic whole-population screening, as opposed to selective investigation of symptomatic patients, for inherited metabolic disease. Much current interest is focused on newborn screening by tandem mass spectrometry, which can replace current methods for detecting phenylketonuria and cover a much wider range of diseases. Two observational studies are comparing cost-effectiveness of tandem mass spectrometry screening versus symptomatic diagnosis in either concurrent or historical control populations. A number of other studies are assessing screening performance against predetermined criteria but without any formal control group. Medium-chain acyl-CoA dehydrogenase deficiency is the most common of the additional diseases being detected and it seems that octanoylcarnitine in blood is a particularly sensitive indicator: some of the cases detected by screening have genotypes suggesting a relatively low risk of serious metabolic decompensation. Ongoing studies should provide further quantitative and qualitative data but will not in themselves define the optimum balance between screening sensitivity and specificity.