Neonatal biochemical screening for disease.

Background: The practice of screening the neonatal population for certain diseases by biochemical testing of a dried blood spot is an established public health initiative in many countries. The diseases for which screening is done vary from region to region, based on ethnic, financial and political considerations. Criteria have been established to identify diseases suitable for neonatal screening.

Diseases Screened: In Western countries, screening for phenylketonuria (PKU) and congenital hypothyroidism (CH) has been introduced throughout. Subsequently, cost-benefit analysis has confirmed the existence of a financial benefit. Other diseases screened for in some regions include galactosemia, aminoacidemias and organic acidemias, cystic fibrosis, congenital adrenal hyperplasia, biotinidase deficiency, hemoglobinopathies, glucose-6-phosphate dehydrogenase deficiency, and Duchenne muscular dystrophy, although in no case has a clear financial benefit been established.

Conclusions: Since the introduction of neonatal screening over 40 years ago, new methods have resulted in an increase in the number of diseases amenable to screening, better automation and greater specificity. Methods currently used include growth of an inhibited bacterial auxotroph (the original phenylalanine (phe) method of Dr. Robert Guthrie), spectrophotometry, fluorometry, immunoassay, and tandem mass spectrometry with electrospray ionization.