This is to detect in children with cystic fibrosis or cystic fibrosis.
To do this, we must highlight a sweat secretion abnormally rich in sodium chloride.
The examination is essentially practical in children.
Formerly, the sweat was collected on a pad placed in the back or the forearm. For sweating, external heating is made use or wrapping and dosait chlorine and sodium sweat.
Now, a collecting electrode is used which automatically makes the assay after stimulation local sweating by electrical or chemical method (pilocarpine). The examination lasts 5 to 7 minutes and is completely painless.
It is negative, and therefore eliminates the CF, so the rate of Na + or Cl- is less than 40 mmol / L of sweat.
– More than 70 mmol / L, it is positive but to signify the disease, it must be retrieved three successive examinations, possibly in two or more laboratories;
– Between 40 and 70 mmol / L, one can not say anything, and the confrontation of clinical and other laboratory results will decide.
100 mmol / L is the upper normal value.
Related to poor supervision, the risk is that of dehydration in a child small or in poor condition, especially if a method of external heating is used.
The test is simple to perform with a toddler, safe and painless, so easy to recommend.