Letter: Screening for cystic fibrosis.

We read with interest Dr Raine's paper but would like to stress 
that Hellsing and Kollberg used a single radial immunodiffusion method not 
radioimmunoassay. Prosser et al. demonstrated quite clearly that similar results were 
obtained in cystic-fibrosis (C.F.) screening with test-strips and with more elaborate 
methods of albumin detection in meconium. Using both radial immunodiffusion as 
well as test-strips, Kollberg's group noticed a decreased albumin content in 
C.F. meconium stored at room temperature and mailed for several days. 
Diminished albumin concentration might have been brought about by remaining proteolytic 
activity. Prosser et al. found no change in albumin content during 
refrigerator storage. Approximately 10% of C.F. cases have no raised albumin 
content in meconium and this problem has not yet been solved. 
