Letters to the Editor

Abstract

18 December 2007 Dear Editor, COMMUNITY-WIDE SCREENING FOR CYSTIC FIBROSIS CARRIERS COULD REPLACE NEWBORN SCREENING FOR THE DIAGNOSIS OF CYSTIC FIBROSIS In their annotation about carrier testing for cystic fibrosis (CF),1 Professor Massie et al. suggest in their title that this could replace newborn screening. Nowhere in their article do they actually canvass this idea, however, and that may be just as well. As CF is a relatively frequent and life-shortening disease the authors are surely right that couples should be offered carrier testing (individual or couple testing or some other model) so as to have a choice about reproductive options. However, at present, this option is nowhere in the world offered as an organised programme. When researching the question for a commentary recently,2 I found that the East Lothian (Edinburgh, Scotland) programme referred to3 has all but stopped, because of very low uptake, and in Denmark, where CF newborn screening was never introduced because the prenatal carrier testing option was considered superior, this has never been implemented.4 Therefore, prenatal carrier testing cannot at present be assumed as likely to be a success as a community programme. Newborn screening and prenatal carrier testing have different aims and different end-points, but the overall aim is to reduce the burden of CF. A successful carrier testing programme with 90–95% coverage would indeed probably render newborn screening unnecessary. However, the costs are quite different. The incremental cost of CF newborn screening in NSW is $2.00 per baby screened. The cost of carrier testing would be high, and may currently be over $100 per couple, or more. A woman and her partner might need to be tested only once, rather than for every pregnancy, as Massie et al. suggest,1 which would cut the cost, but people re-partner, move around and even forget their testing status, so this saving might not be a safe policy. With any model, there will be a residual risk of CF for offspring. With the current pilot programme in Victoria, this is very low for tested couples, but adding in those not accepting testing, those not able to pay, those who for a variety of reasons slip through the net (12% of first antenatal visits are at over 20 weeks' gestation), it does not seem likely that carrier testing will replace newborn screening in the near future, and it would be a pity if jurisdictions thought that it might. The annotation canvasses an important issue. The title seems wrong for 2007, and does not reflect the content.