sweat chloride ??

My daughter has had various symptoms....growth issues, ravenous appetite without gaining weight, a nose that is always running for over a year....sometimes not so much.....sometimes gunky and worse to name a few. She's had an endoscopy to rule out GI issues and other various tests. She had the infant blood screening for CF and that was negative.

Long story short...she had a sweat chloride test done yesterday.........her first number was 58..........so they did the test again on a different arm......that number was 70...........they did a third on her leg....that was 67.

We had it done in a hospital and now our Dr. wants to have it done again down at the specialty area. Everything I am reading says sweat chloride tests can have false negatives..........I am not finding anything about false positives.

What are ANYONE'S thoughts. I have to wait until Friday and I can't help but think she more likely than not has CF????????? Besides the other "rare" diseases.........would there be false positives????????? Also......what's the difference between various sweat chloride testings....ie. My daughter's was not a guaze and patch.......it was a drop of purified water put into 2 devices strapped to her arm with electrode like things.......the results came up on the computer???????????

Never heard of a false positive. Only a false negative, such as in the case of our son. His was a normal 32 done at an accreditted CF facility.

With genetic screening, testing, they usually only test for about 30 of the most common genetic mutations. Ambry Amplified and Qwest test for over 1300 different CF mutations. I would push for genetic testing and ask in the meantime if they could do a throat or sputum culture. See if she's growing any bugs that are common to CFers such as psuedomonas.

I also see that you're located in Minnesota. U of MN is one of the top CF clinic in the nation. There's also an accreditted facility at Minneapolis Childrens, though in our area, the majority go to the U.

Are you absolute certain they did a sweat chloride....sounds more like a sweat conductivity test....my daughter (2 1/2yrs old) had one done a few months ago...thought it was a new way to do sweat chloride but when we got the results (57) her doctor said"normal" because the lab said it was normal...so I investigated and asked the lab what kind of test...the doctor didn't know it was NOT a sweat chloride but a sweat CONDUCTIVITY test...different and not the gold standard and definately not used to diagnose CF....sweat chloride uses the gauze...sweat conductivity uses a machine with "electrode" kind of things that hook to a machine that reads the test immediately. We're going to childrens hospital in Milwaukee to have a sweat chloride test done and genetic testing......hope this was helpful?! I know how crazy it can make you feel ....I'm curious to know how it turns out. god bless.

Yes, I did some more research on the internet and it was in fact the sweat conductivity test--specifically the Nanoduct. From the research I have read the last couple of nights, it actually is as reliable as the the sweat chloride test. HOwever, I was told by my Dr. that a sweat chloride test was to be done.

We are headed to Mpls. Children's on Friday. Do you think that with three positive sweat conductivity tests we should insist on gentic testing? Or wait to see what their sweat chloride says first and then do it?

Any help is appreciated!

You're going to be at the clinic anyway. I'd insist on having them do the genetic blood test, so they can start the process. I believe with the ambry amplified, it can take several weeks. In our case, DS had one of the most common mutations and I'm assuming his testing only included the top 32 'cuz his went to Mayo and we had the results by the end of the week.

DS was diagnosed at Minneapolis Childrens and that's where his CF doctor sends him for CT scans & xrays.

My daughters number on the sweat conductivity was 57....good for your doctor for following up on it...ours wanted to say it was normal...I believe the CF foundation says that if a hospital does a sweat CONDUCTIVITY test then they should use 50-80 as borderline but the manufactuers use 60-80 as borderline....I did call 3 CF accredited centers about this conductivity test and they don't use it...they also state it isn't to be used for diagnosing...only a "screening". We're going to Childrens hospital in Milwaukee and I just spoke to NP there...she state they plan on doing blood test also. I think it's a good thing..be as thorough as possible. Good luck at your appt.

We called our Dr. and talked with his assistant so full testing would be ordered tomorrow.....regardless of what the new sweat chloride results are.

Could you tell me.....after they do the sweat chloride test what is the process? Wait for results at the hospital? Meet with Dr. or genetic counselors? They wouldn't send us home without some sort of plan would they? I am starting to go back in panic mode. I hate the unknown!

How did it go...I started to respond to your post but when I read back I realized you should have done the Dr. visit....I went out of town on friday....what were the results, who did you meet with, ect. I'm in the same position you were...our app. is the end of Feb. and I have a lot of questions.