Call for routine cystic fibrosis screeningBMJ 1997; 315 doi: https://doi.org/10.1136/bmj.315.7113.899f (Published 11 October 1997) Cite this as: BMJ 1997;315:899
A specialist group has called for more health authorities in Britain to consider testing newborn babies for cystic fibrosis. The call comes as more evidence of the benefits of early diagnosis has emerged from a large study in the United States.
Over 650 000 newborn babies were screened for cystic fibrosis in a trial carried out by the Wisconsin Cystic Fibrosis Neonatal Screening Study Group, but only half of them were given the sweat test to confirm the disease-the rest were diagnosed by standard methods (symptoms, family history).
The investigators found that cystic fibrosis was diagnosed much earlier with screening-at age 3 months compared with 18 months. Children given the sweat test matched charts showing recommended height and weight for age better than controls at the time of diagnosis and throughout the 10 year follow up because they had not become malnourished in their early life. All patients were given high calorie diets, pancreatic enzyme treatment, and fat soluble vitamin supplements as they needed them (New England Journal of Medicine 1997;37:963-9).
The researchers conclude that neonatal screening for cystic fibrosis can prevent malnutrition in infants, leading to more normal growth in childhood with potential long term benefits on lung function. They add that so far no long term risks of screening have been identified and that it is no more expensive to diagnose cystic fibrosis by screening than by clinical methods.
In an accompanying editorial, specialists from the Netherlands conclude: “Many objections against routine screening that were justified in 1983 have gradually disappeared, as the evidence has accumulated that early diagnosis and treatment are beneficial and that screening probably saves money and carries no harm of its own.”
Neonatal screening for cystic fibrosis is carried out in five areas in Britain-East Anglia, Trent, Northamptonshire, Wales, and Leeds, covering about 16% of all births. The Cystic Fibrosis Trust believes that cystic fibrosis conforms to the World Health Organisation's criteria for screening for genetic disease and that testing should be nationwide.
Dr Rodney Pollitt, director of Trent's neonatal metabolic screening programme, has been screening for cystic fibrosis for eight years. In a report on neonatal screening for metabolic disorders commissioned as part of the NHS's health technology assessment programme, Dr Pollitt and his coauthors conclude that wider screening for cystic fibrosis in infancy should be encouraged.
There are problems with the test, admits Dr Pollitt. About 10% of cases are missed, the test is not very good at pinpointing pancreatic dysfunction, and it picks up cystic fibrosis carriers, which means that these people are sent for genetic counselling without requesting it. But overall the benefits of screening outweigh the drawbacks.
“I started off very sceptically about cystic fibrosis screening, but the more we see parents and children, we know we are doing good. All paediatricians who are involved in the system feel that screening is a great advance. Indications are that it can improve life expectancy by slowing down the disease, and it certainly saves parents a lot of anguish,” said Dr Pollitt.