Sweat test and diagnostic algorithm

Question

Hello dear team,
there are patients who had a negative sweat test and diagnostic algorithm, however the function of the pancreas is not given anymore and the course of the illness is like in CF patients. Pneumonias, infections, etc. Both of my children are in the meantime 27 and 28 years old, however acutally these investigations had been done to one of them and showed, that the chloride channel was functioning. However all other symptoms favour CF. I am a bit irritated with the diagnosis of CF after such a long time. We have been told, that it could not be CF.
Many thanks for your help.

Answer

Hello,
the sweat test is the so-called gold-standard for the diagnosis of CF. In rare cases, there are CF patients who have a negative sweat test. In case of ongoing suspicion of CF in spite of a normal sweat test, the patient should visit a certified CF Center and there, further diagnostics (human genetic investigation, nasal potential difference measurement, intestinal current measurement) should be discussed.
A diagnostic algorithm can also be found in the S2-consensus-guideline "diagnosis of CF". Here is the link [article in German]:
www.awmf.org/uploads/tx_szleitlinien/026-023lS_2k_Diagnose_der_Mukoviszidose_2013-07.pdf

I hope to have helped you with the remarks and stay with my best regards,
Yours
Dr. med. Christina Smaczny

03.04.2017