What is a sweat chloride test?
Pot chloride test is used to diagnose a child that can have cystic fibrosis. People with cystic fibrosis have a gene mutation that causes secretion of excess mucus and other body fluids, leading to a number of symptoms that include increased susceptibility to lung infections. This genetic disease considerably shortens the life of affected individuals with average age of survival slightly less than 37 years. Pot chloride test is a simple test that has been the main diagnostic test for cystic fibrosis for more than four decades. In most cases, the test is performed in children. When normal sweat glands are active, salt and water are transmitted from these glands. Most of the salt is then reabsorbed into the sweat glands and leaves only a small amount of salt in the form of sodium ions and chloridue ions. In people with cystic fibrosis, there is a mechanism that reabsorb salt, defective. As a result, the amount of sodium and chloride on the skin is much higher than usual.
During the test, the tested child will have a chemical caused by sweat applied to its skin, usually on a leg or forearm. Once applied, an electrode is placed on the surface and a small electric current is applied for sweating stimulation. This electric current is minimal and causes only a slight feeling of armor or a feeling of heat on the skin. After the electric current is applied, the baby's skin is shaken by filter paper to collect sweat. The whole test takes 30 to 60 minutes.
The results of the sweat chloride test are evaluated based on the amount of chloride in the sweat. Normal sweat chloride levels are between 10 and 35 milliequivalents per liter. In order to diagnose cystic fibrosis, the child must have the level of sweat chloride more than 60 milliequivalents per liter in two tests performed by two different days.
Children with a sweat chloride test between 35 and 60 milliequivalents per liter may have a milder variant of cystic fibrosis or may not have a diseaseat all. In these cases, the test is repeated, usually at least once to ensure that false or false negative results have not been obtained.
Another reason is the important testing is that certain health conditions can distort the results of sweat chloride tests. For example, children with cystic fibrosis that are malnourished may have normal sweat chloride levels when testing. In addition, a child who does not have cystic fibrosis can test this disease positively if it has a different condition, such as a pancreatic infection or thyroid disease or pituitary.