It depends upon how old she is. Babies/newborns have difficulty providing an adequate sample, so sometimes there are a lot of false negatives. A 33 would be considered normal for most people -- 0-40 normal, 40-60 borderline and 60 plus is a postivie. Unfortunately, sweat tests aren't always accurate. DS had a normal 32; however, genetic testing showed CF. IMO, they should push for genetic blood testings to get an accurate result.