CF Sweat Test

[anonymous]

Hello Everyone
I have a question... hope it doesn't sound too dumb!!! My sister is going to our CF center to be sweat tested and she would like to know if one eats alot of salt all of the time will that affect the sweat test results? I personally think that she should be DNA tested because her niece does have CF. your responses would be greatly appreciated.

kaitsmom<img src="i/expressions/rose.gif" border="0">

 

[thefrogprincess]

The sweat test really is sort of obsolete now, it can give a false negative which is no good. Genetic testing is much better especially if there is family history. I would recommend the genetic test no matter what the outcome of the sweat test is. Just be sure its done by Ambry, they do the most thorough testing. As far as eating lots of salt affecting the results I have no idea what would happen. It would make sense that it could change the outcome though.

 

[anonymous]

Kaitsmom,
NO, eating a lot of salt will NOT give you a false positive on a sweat chloride test. With the exception of lab error, there are a few rare conditions that will give an adult a positive result on the sweat chloride test that are NOT cf related. One more thing, the sweat test is still considered the "gold standard" for diagnosis but in difficult, borderline cases, or the case of siblings, a genetic test may be used instead or in conjunction with the sweat test for diagnosis. I'm guessing the reason they're doing the sweat test on your sister is they do not know which mutations she could have. They only know the mutation that your dd inherited from you, since the other mutation was inherited from your dh's side of the family. Therefore, they know ONE mutation that your sister could have but not both. I hope that helps and is not confusing. Just my opinion, but if your sister has a high negative (30s) or borderline sweat test, I'd follow it with genetic testing through ambry. Hope that helps.

 

[anonymous]

Thanks Guys
she goes in 2 weeks and i am trying to stress to her the DNA test, i hope that she follows through with all of this

Kaitsmom<img src="i/expressions/rose.gif" border="0">