The sweat chloride test is primarily used to diagnose which condition?

The sweat chloride test is primarily used to diagnose which condition?

• A. Cystic fibrosis
• B. Asthma
• C. Chronic bronchitis
• D. Bronchiolitis

Answer: (A)

The sweat chloride test is primarily utilized to diagnose cystic fibrosis, a genetic disorder that affects the exocrine glands, leading to the production of thick, sticky mucus. This test measures the concentration of chloride in the sweat—a hallmark sign of cystic fibrosis. In individuals with this condition, the chloride levels in sweat are significantly elevated due to defective ion transport caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The high concentration of chloride in sweat is a direct consequence of the impaired functioning of this gene, which normally regulates the movement of salt and fluids in and out of cells. When the CFTR protein is dysfunctional, chloride and sodium ions are not properly absorbed, resulting in increased amounts in sweat. Therefore, this test is an essential diagnostic tool for identifying cystic fibrosis in newborns and symptomatic individuals. The other conditions listed—asthma, chronic bronchitis, and bronchiolitis—do not typically involve elevated sweat chloride levels and are diagnosed through different clinical assessments and tests, emphasizing the specificity of the sweat chloride test for cystic fibrosis.

The sweat chloride test is primarily utilized to diagnose cystic fibrosis, a genetic disorder that affects the exocrine glands, leading to the production of thick, sticky mucus. This test measures the concentration of chloride in the sweat—a hallmark sign of cystic fibrosis. In individuals with this condition, the chloride levels in sweat are significantly elevated due to defective ion transport caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

The high concentration of chloride in sweat is a direct consequence of the impaired functioning of this gene, which normally regulates the movement of salt and fluids in and out of cells. When the CFTR protein is dysfunctional, chloride and sodium ions are not properly absorbed, resulting in increased amounts in sweat. Therefore, this test is an essential diagnostic tool for identifying cystic fibrosis in newborns and symptomatic individuals.

The other conditions listed—asthma, chronic bronchitis, and bronchiolitis—do not typically involve elevated sweat chloride levels and are diagnosed through different clinical assessments and tests, emphasizing the specificity of the sweat chloride test for cystic fibrosis.