Question

• Will screening for cystic fibrosis in newborns improve overall health by detecting disease earlier?

Clinical Bottom Lines

1. Introducing immunoreactive trypsinogen (IRT) & DNA screening for CF in newborns can improve the overall health of CF patients.
2. The positive likelihood ratio of CF screening with IRT & DNA analysis is 950.

Summary of Key Evidence

1. A prospective, randomized clinical trial of CF screening was performed on all Wisconsin newborns from 1985 to 1995 with IRT or IRT and DNA testing.¹
2. A sweat chloride test was applied as a gold standard to all patients in the early diagnosis group.¹
3. CF screening can detect CF on average 60 weeks or approximately one year earlier.¹
4. Improved nutrition and pulmonary function have been identified over a 10-year period for patients in whom CF was detected as a newborn.^1,3
5. CF screening is comparable in cost to PKU screening ($10,150/ CF patient identified in 1995) with a higher positive predictive value.¹
   

Additional Comments

• Inpatient stays can be decreased in the first two years of life with early CF detection.³
• Pancreatic function is not generally preserved with early CF detection.^1,3
• Buccal cell DNA mutation analysis can detect 20% of cases of CF in symptomatic infants, although 1% of patients with CF may be missed due to false negative testing.⁴
• Follow-up studies from the Wisconsin study indicate more benefits than presviously thought.⁵

Citation

1. Farrell PM, Kosorok MR, Laxova A, et al. Nutritional benefits of neonatal screening for
   cystic fibrosis. N Engl J Med 1997; 337: 963-9.
2. Gregg RG, Simantel A, Farrell PM, et al. Newborn screening for cystic fibrosis in Wisconsin: Comparison of biochemical and molecular methods. Pediatrics 1997; 99: 819-24.
3. Waters DL, Wilcken B, Irwig L, et al. Clinical outcomes of newborn screening for cystic
   fibrosis. Arch Dis Child Fetal Neonatal Ed 1999; 80: F1-F7.
4. Parad RB. Buccal cell DNA mutation analysis for diagnosis of cystic fibrosis in newborns
   and infants inaccessible to sweat chloride measurement. Pediatrics 1998; 101: 851-5.
5. Frangiskakis S. Currently There is Insufficient Evidence to Support Newborn Screening for Cystic Fibrosis. EBM CAT, 12/2000.
   

CAT Author: Susan Henrikson, MD

CAT Appraisers: Kenneth Pituch, MD

Date appraised: October 29, 2003