Anyone diagnosed with CF with a very negative sweat test?

[sanfloraine]

My son is 4, PI and his new CF team is unsure as "does if have CF or not"? Kind a mystery diagnostic: he has been PI for 3 years, his last fecal elastase was 92 and he also completely flunked a 72 hours fecal test, he was already on Zenpep and they put him on the AquaDeck vitamins as well. Sounds like CF from a pancreas point of view... but he has had 3 sweat tests over the years at 2 different places (approved CF labs): all were super negative (10-15). He had a fairly complete genetic test of 1500 mutations that showed nothing a few years ago (but not the Ambry one, this one did not have the indel mutations) and he is in super shape and does not look like a kid with CF. Some mild lung problems: mild asthma at times, 2 sinusites and 20 ear infections.

They're having us repeat the sweat test, the genetic test (from Ambry this time) and a new throat culture.

If his sweat test were negative but borderline, they would say he has CF... but it's not! They told us they do not know of anyone who has CF and a very negative sweat test so I am wondering if anyone here was diagnosed with CF with a very negative sweat test?

 

[Melissa75]

Here is a thread from the past with information relevant to your question. (A change in message board software since the thread was started caused every post in it to be repeated a few times, but while it isn't actually six pages worth of responses, there's some good info in there for you.)

http://forum.cysticfibrosis.com/threads/24205-Sweat-Chloride-Test-Poll

 

[Printer]

I had two sweat tests, a month apart, each was on the high side or normal.

Bill

 

[Beccamom]

I am diagnosed with CF with a borderline sweat test and 2 CF causing mutations. However, my daughter has no diagnosis but her FEV1 increased from 50%to holding in the 90s after CF treatment mucus clearance vest hypersal neb and antibiotics based on sputum culture. We both culture typical CF bacteria, but not the same bacteria.

I think doctors are too arrow minded about diseases and do not consider how one affects another. My daughter is genetically a CF carrier of my stop codon mutation so she only has 50% CFTR function and she has Ehlers Danlos syndrome a connective tissue disorder that causes all connective tissue to be too flexible. I believe her lung diseases, Gastroparethesis, malabsorption of vitamin D, failure to thrive, chronic sinusitis requiring surgery, nasal polyps, etc are caused by how having EDS and having 50% CFtR function interact with eachother.

My second child has my minor CFTR mutation and so much more CFTR function. Her lungs are perfectly healthy. She is flexible also but not necessarily enough for an EDS diagnosis. I think she is a carrier for both EDS and CF but has neither.

I hope this helps others.

My son is 4, PI and his new CF team is unsure as "does if have CF or not"? Kind a mystery diagnostic: he has been PI for 3 years, his last fecal elastase was 92 and he also completely flunked a 72 hours fecal test, he was already on Zenpep and they put him on the AquaDeck vitamins as well. Sounds like CF from a pancreas point of view... but he has had 3 sweat tests over the years at 2 different places (approved CF labs): all were super negative (10-15). He had a fairly complete genetic test of 1500 mutations that showed nothing a few years ago (but not the Ambry one, this one did not have the indel mutations) and he is in super shape and does not look like a kid with CF. Some mild lung problems: mild asthma at times, 2 sinusites and 20 ear infections.

They're having us repeat the sweat test, the genetic test (from Ambry this time) and a new throat culture.

If his sweat test were negative but borderline, they would say he has CF... but it's not! They told us they do not know of anyone who has CF and a very negative sweat test so I am wondering if anyone here was diagnosed with CF with a very negative sweat test?

 

[Justinsmama]

Hi,

My son has a mutation (F1052V) that gives a negative sweat test. He was originally tested because of PI. At 7 he developed lung issues (4 pneumonias). Genetics just confirmed this year, after being diagnosed two and a half years ago on clinical. Second mutation was re-classified this year. Good luck!!

 

[sanfloraine]

Thank you all for your answers! We have not yet restarted the tests, waiting for the nurse to schedule them. I am really curious about his new genetic test results.

I don't know if I am a carrier for CF but I know I battled breathing problems for many years, I am doing quite good right now but had to change career because of these problems.

Justinsmama: I remember your son, you had discussed his problems when I joined the forum 2.5 years ago. And I could not help thinking there were similarities with my son, my son's fecal elastase is going down but a bit more slowly. No pneumonia here - for now. We were told a while back that if he starts developing pneumonia that he will be diagnosed with CF for sure. I did not know that some mutations could give a negative sweat test!

 

[Gibson75]

My 2 year old has had 3 sweat tests, all below 15. His newborn screen was positive for one mutation DF508 which I was aware that I was a carrier. After he passed the sweat test he went onto become quite sick. He is PI with his GI specialised ruling every other disorder out saying it has to be CF. He is seen at the CF clinic every 3 months but they are sceptical about diagnosing due to his low sweats. We paid for genetic tests which showed another mutation (1716G>A) which was documented in the report as being associated with PI and Cf symptoms but is listed on CF database as being non disease causing. He continues to have a daily cough, has cultured Heamaphilus influenza and staph A. He also wrinkles excessively in the water. I know it is extremely frustrating but keep onto the doctors. I would hate to imagine how my fella would be now if I didn't keep pushing. They said they would sweat test him again when he is 5. Goodluck keep us posted.

My son is 4, PI and his new CF team is unsure as "does if have CF or not"? Kind a mystery diagnostic: he has been PI for 3 years, his last fecal elastase was 92 and he also completely flunked a 72 hours fecal test, he was already on Zenpep and they put him on the AquaDeck vitamins as well. Sounds like CF from a pancreas point of view... but he has had 3 sweat tests over the years at 2 different places (approved CF labs): all were super negative (10-15). He had a fairly complete genetic test of 1500 mutations that showed nothing a few years ago (but not the Ambry one, this one did not have the indel mutations) and he is in super shape and does not look like a kid with CF. Some mild lung problems: mild asthma at times, 2 sinusites and 20 ear infections.

They're having us repeat the sweat test, the genetic test (from Ambry this time) and a new throat culture.

If his sweat test were negative but borderline, they would say he has CF... but it's not! They told us they do not know of anyone who has CF and a very negative sweat test so I am wondering if anyone here was diagnosed with CF with a very negative sweat test?

 

[sanfloraine]

My 2 year old has had 3 sweat tests, all below 15. His newborn screen was positive for one mutation DF508 which I was aware that I was a carrier. After he passed the sweat test he went onto become quite sick. He is PI with his GI specialised ruling every other disorder out saying it has to be CF. He is seen at the CF clinic every 3 months but they are sceptical about diagnosing due to his low sweats. We paid for genetic tests which showed another mutation (1716G>A) which was documented in the report as being associated with PI and Cf symptoms but is listed on CF database as being non disease causing. He continues to have a daily cough, has cultured Heamaphilus influenza and staph A. He also wrinkles excessively in the water. I know it is extremely frustrating but keep onto the doctors. I would hate to imagine how my fella would be now if I didn't keep pushing. They said they would sweat test him again when he is 5. Goodluck keep us posted.

Thank you for your answer, this confirms my fears that my son probably has CF. I know that in some countries (Belgium?) sweat tests are not taken into account anymore because they are not always reliable. Right now we are waiting to hear back about the lung doctor to re-order all the tests and from the GI specialist as well, he did a bunch of tests to rule out CF... that was 3 weeks ago and no answer back from him. We'll keep pushing for more answers.