Hi, Unless there have been major improvements in the last 19yrs on how they conduct the sweat test, we were told an adequate sweat test could not be done on a newborn because of the ability to get adequate amounts of sweat from a newborn. We were told at Duke that newborns up to almost a year often get a negative or borderline sweat test due to their inability to sweat enough or adequately. Our youngest was borderline from the age of one month and had her last sweat test at about one year which still came up borderline. We were told they were 99% sure she had CF due to her genetic markers lining up with our oldest, who had just been diagnosed a week before Rachel's birth. They treated her as positive for CF.
Over the years no one, not even us, thought to have her sweat test redone until she was 10.
Like everyone else has suggested, ask for genetic testing. At the very least, it will rule it out. Crossing CF of the list of what could be wrong was what lead to our oldest daughter's diagnosis, and he had her tested twice at two different hospitals just to be sure.
I hope you get a definative answer about your grand daughter.
