Letter: Detection of cystic fibrosis and heterozygotes.

During the past year, we have developed a new assay for cystic 
fibrosis by utilising the Ussing chamber technique and measuring the electrical 
properties of rat jejunum in the presence of the sera to 
be tested. The potential difference (P.D.) and resistance (R.) are measured 
with a sensitive electrometer at 5-minute intervals over 60 minutes. We 
were able to detect 90% of the heterozygotes. The possibility of 
detecting the remaining 10% is present, and can, we feel, be 
achieved by using a more concentrated specimen. 