New technologies extend the scope of newborn blood-spot screening, but old problems remain unresolved.

UNLABELLED: The potential of newborn blood-spot screening is expanding rapidly with the development of new analytical techniques and treatment methods. At the same time, some existing programmes, particularly that for congenital hypothyroidism, are coming under scrutiny because of suspicion that they are being shaped by analytical performance rather than evidence of clinical need. Screening policy varies greatly from country to country. CONCLUSION: Ethical and political considerations may sometimes override formal scientific decision models.