All newborn infants in East

Aim-To investigate whether analytical methods based on the colligative physical chemical properties of ions or solutes in sweat are less eVective than the specific measurement of electrolytes in the diagnosis of cystic fibrosis (CF). Methods-A single sweat sample was collected (Macroduct) from each of 211 infants and children, of whom 57 had CF, for the measurment of sodium, chloride, osmolality, and conductivity. Results-The ranges within which CF and non-CF individual values overlapped (equivocal ranges), were wider for sodium and osmolality measurement than for chloride or conductivity. Neither of the latter two measurements provided a discriminatory advantage over the other. The utilisation of broadly based age related ranges for non-CF control subjects served to improve the discriminatory power of all four measurements to an extent that, in this cohort, both chloride and conductivity provided complete discrimination. Conclusion-Sweat conductivity is as effective as chloride measurement in the laboratory diagnosis of CF. (Arch Dis Child 2000;82:420-424)

the wide inter-individual variability in AAA expansion rate is likely to reflect complex genetic and environmental interactions, but the lack of any relationship with ACE genotype suggests that differences in vascular ACE activity in aortic tissue are not major determinants of the variability in rate of AAA dilatation.

This review summarises the trajectory of neonatal screening strategies for the detection of cystic fibrosis (CF) using the measurement of Immunoreactive Trypsin (IRT) in dried blood spots (DBS) from 1979 until the beginning of the 21st century when newborn screening (NBS) programmes started to spread throughout many countries, using IRT measurement combined with a CF genotype analysis of DBS.

The diagnosis of screen-positive babies proved difficult in a minority of cases with the classification of some patients changing with evolving phenotype. Our results illustrate the importance of collecting outcome data over a long time period for accurate assessment of the screening programme. This study provides evidence that newborn screening for CF is a valid undertaking that detects 95% of unsuspected CF cases presenting before 3 years of age.