It is good that your daughter has been gaining weight, however, she is not at the weight she should be for her age. That is probably why your MD wants the sweat test done to rule out CF. Children with CF gain weight very slowly. A sweat test is done on the surface of your child's skin and they measure the chemicals from her sweat. It takes about 30-60 minutes. I suggest you get a second opinion from another MD about the sweat test. Best of luck.
She has not lost any weight, in fact she keeps gaining. But she is in the less than 5% for her weight and in the 48% for her height. She exhibits none of the sytems of CF. Her stool is normal and her lungs have always been clear and were today. I just hate to do a test that may not be needed. She was breast fed for the first 5 months of her life.
Has she been steadily losing weight? What percentile is her height and weight? I know it is a hardship to do the sweat test, however, if your MD recommended it, it should be done. Malabsorption may do show at an early stage of the disease. The sweat test is the only way to test CF at this age.