Which of the following can be used in the diagnosis of cystic fibrosis?1. An elevated potassium level in the sweat2. An elevated chloride level in the sweat3. Genetic testing of the parents4. An elevated blood level of immunoreactive trypsin

The diagnosis of cystic fibrosis can be done using the following methods:

1. An elevated potassium level in the sweat: This is not typically used in the diagnosis of cystic fibrosis. The sweat test for cystic fibrosis actually measures the amount of chloride, not potassium, in the sweat.

2. An elevated chloride level in the sweat: Yes, this is one of the primary tests used to diagnose cystic fibrosis. People with cystic fibrosis have two to five times the normal amount of chloride in their sweat.

3. Genetic testing of the parents: Yes, this can be used in the diagnosis of cystic fibrosis. If both parents are carriers of the faulty gene that causes cystic fibrosis, there is a 25% chance their child will have the disease.

4. An elevated blood level of immunoreactive trypsin: Yes, this can be used in the diagnosis of cystic fibrosis. Newborns with cystic fibrosis often have a higher than normal level of a chemical called immunoreactive trypsinogen in their blood.

So, the correct answers are 2, 3, and 4.