Diagnostics

Question

My two-year-old son has had prolonged problems with failure to thrive and digestion problems (gastroesophageal reflux, flatulence, malodorous oily mushy stool once a day or every other day). He is often tired and weak. I have also noticed that there is very thick mucus in his nose (I clean his nose every day, so there isn´t too much of the mucus, but it seems rather thick to me). The results of all tests done on my son (blood, urine, antibodies against transglutaminase, uric acid, stool for bacteria and viruses etc.) are normal. Now my son has undergone a sweat test in our regional hospital. The result was negative (16). I was told that the low test result rules out the possibility of my son having CF. Does it really mean that I don't have to worry about him having CF, or would you recommend further tests or having the sweat test repeated at a specialized laboratory?

Answer

Hello,

We understand that you are worried about your son´s health. Needless to say, the problems that you describe aren´t entirely typical for CF, since your son apparently doesn´t suffer from airway infections. However, detailed testing is definitely advisable. In order to rule out CF as the cause of your son´s not thriving and digestion problems, we suggest a stool test for elastase-1. The test is simple and it´s enough if you send a small sample of your son´s stool in a properly closed container to a specialized laboratory by post.

If the sweat test result is as low as you state, CF diagnosis in your son can be indeed almost certainly ruled out. It is however important that the sweat test is carried out by a laboratory which has relevant experience with it (as it does it frequently) and which uses the so-called pilocarpine ionotophoresis for measurment of the chloride concentration in the sweat. If you are still worried that your son might have CF, you can easily have the sweat test repeated at a specialised laboratory.
Dr. J. Brázová

22.11.2011