negative sweat test..

[anonymous]

Hi,
I was wondering if its possible to get a low sweat test score (like 9--really low), but still have CF? I know that if you're borderline, you should continue on with the blood test? Any need to do so with a score this low? The only reason I ask is that my 3 year old DS can't seem to get over this diarrhea, vomiting, "cold" thing that he's got...its been three weeks! He's always gotten colds and stuff, but they never seemed real major so I didn't worry. But he's also WAY low on the weight chart-not even making it into the bottom 5 percentile...am I just worried cause DD was diagnosed, or is there a real cause for concern?

 

[anonymous]

at about 3 months my daughter was given a sweat test and it came back negative, so they ruled CF out. After being in and out of hte hositipal constaintly for "failure to thrive" as well as RSV and phnuemia (sp??) and other stuff, they finally did a genetic study. She came back positive for CF. When the test came back they admitted her again and she had phnuemionial (sp???) really bad. The nurses told us later they didn't think she would make it through that night. She's now 2 1/2 yrs old and doing good.

Anyway, I'm not a fan of sweat tests. I shouldn't be so down on them, my daughter was really to small to have the test done on her, and the CF doctor later said the lab was having problems at that time, but still, I'm not a fan of sweat tests.

I would suggest getting a genetic study if you think there are some CF issues there.

 

[anonymous]

I'm in a similiar boat. We actually did the genetic panel through genzyme and it was completely negative. Two out of three doctors think thats good enough. The third does not but is "just" an ENT and so won't order the extended panel. Do you know your dd's mutations? If so, it should be relatively easy to have him tested - just test for her mutations. If not, then I'd suggest the extended panel because my gut feeling is just that if his sweat test was a valid test, then his mutations would more than likely be rare to cause such a low result... If you know dd's mutations, just approach it with the dr from the standpoint that you want to know for future reference, your ds's carrier status and they may be more willing to test.

 

[julie]

Am I reading correctly that your daughter was diagnosed????????????


If that is correct, I would DEFINATELY get a blood test!!!!!!!

Yes, people can have a nonexistant sweat test level (or VERY low) and still have 2 CF mutations found. It isn't common, but it does happen.

 

[Alyssa]

I'm with Julie -- did you mean that your daughter is diagnosed with CF? If so, yes by all means make them do the full genetic testing on your son.

We never would have found the genes in my son or daughter if not for the blood tests. The sweat tests were too close to normal.

 

[rainy]

Hi,
I was wondering if its possible to get a low sweat test score (like 9--really low), but still have CF? I know that if you're borderline, you should continue on with the blood test? Any need to do so with a score this low? The only reason I ask is that my 3 year old DS can't seem to get over this diarrhea, vomiting, "cold" thing that he's got...its been three weeks! He's always gotten colds and stuff, but they never seemed real major so I didn't worry. But he's also WAY low on the weight chart-not even making it into the bottom 5 percentile...am I just worried cause DD was diagnosed, or is there a real cause for concern?

 

[Ratatosk]

I would push for more answers to rule out CF. And if not CF, then what is causing his health issue. The only conclusive determination would be for a blood test. There are over 2000 mutations for cystic fibrosis. While my son has the most common mutation, his sweat test was normal.