Nasal Potential Difference as Part of CF Dx process

mom2owen · May 14, 2011

This is all such good information. I agree that it is helpful that there is something out there that COULD help those of us in this undiagnosed situation. I am frustrated that so many are not getting adequate treatment only because of lab results not being conclusive. I realize you need criterion for diagnosis but I get so annoyed that the whole picture of a patient, including their actual symptoms can be ignored in place of lab results.
I am actually hesitant to do the NPD because Owen's nose and sinuses are "swollen and erythmatous" and he is using sprays at the moment. I contacted Christine at CHOP and she did say he would need to be off his meds before coming and that if he has active inflammation, it would affect the results. If he is not on his meds, he does have inflammation so we are in a catch-22. I would hate to commit to traveling, going through an uncomfortable test to find out nothing! And, to top it off, Owen gets severe bloody noses and I worry if that would happen with the NPD and make the effort fruitless.
At the same time, since we are not given full treatment and what we do get we have had to fight for, it would be worth a shot to try the NPD when we have as good of health as possible.
Another question I have though is how will other clinics respond to test results from an NPD? Even if it is abnormal and indicative of CF could some clinics write it off saying it is experimental? Our clinic here does them but has never even suggested it.

mom2owen · May 14, 2011

This is all such good information. I agree that it is helpful that there is something out there that COULD help those of us in this undiagnosed situation. I am frustrated that so many are not getting adequate treatment only because of lab results not being conclusive. I realize you need criterion for diagnosis but I get so annoyed that the whole picture of a patient, including their actual symptoms can be ignored in place of lab results.
 I am actually hesitant to do the NPD because Owen's nose and sinuses are "swollen and erythmatous" and he is using sprays at the moment. I contacted Christine at CHOP and she did say he would need to be off his meds before coming and that if he has active inflammation, it would affect the results. If he is not on his meds, he does have inflammation so we are in a catch-22. I would hate to commit to traveling, going through an uncomfortable test to find out nothing! And, to top it off, Owen gets severe bloody noses and I worry if that would happen with the NPD and make the effort fruitless.
 At the same time, since we are not given full treatment and what we do get we have had to fight for, it would be worth a shot to try the NPD when we have as good of health as possible.
 Another question I have though is how will other clinics respond to test results from an NPD? Even if it is abnormal and indicative of CF could some clinics write it off saying it is experimental? Our clinic here does them but has never even suggested it.

hmw · May 14, 2011

Positive NPD results are used as acceptable criteria for CF diagnosis for acceptance into many clinical trials, so I would think that this would validate a dx, esp when combined with Owen being SO symptomatic.

When Shawn had his test, the results were accompanied by a letter to the dr who sent him there by the director of research and cf center (Dr. Rubenstein- who works closely with Christine) and he interpreted the results and indicated very clearly that the results were not consistent with a dx of CF etc. So I would think that if Owen had results consistent with CF, the letter to go with results would indicate this pretty clearly- helping to establish this. I would try to get him a full workup while you are there. Esp if the results are positive this may be very helpful.

hmw · May 14, 2011

Positive NPD results are used as acceptable criteria for CF diagnosis for acceptance into many clinical trials, so I would think that this would validate a dx, esp when combined with Owen being SO symptomatic.

When Shawn had his test, the results were accompanied by a letter to the dr who sent him there by the director of research and cf center (Dr. Rubenstein- who works closely with Christine) and he interpreted the results and indicated very clearly that the results were not consistent with a dx of CF etc. So I would think that if Owen had results consistent with CF, the letter to go with results would indicate this pretty clearly- helping to establish this. I would try to get him a full workup while you are there. Esp if the results are positive this may be very helpful.

hmw · May 14, 2011

Positive NPD results are used as acceptable criteria for CF diagnosis for acceptance into many clinical trials, so I would think that this would validate a dx, esp when combined with Owen being SO symptomatic.
 
 When Shawn had his test, the results were accompanied by a letter to the dr who sent him there by the director of research and cf center (Dr. Rubenstein- who works closely with Christine) and he interpreted the results and indicated very clearly that the results were not consistent with a dx of CF etc. So I would think that if Owen had results consistent with CF, the letter to go with results would indicate this pretty clearly- helping to establish this. I would try to get him a full workup while you are there. Esp if the results are positive this may be very helpful.

amyr · May 14, 2011

I had the NPD done and so did one of my children. Their doctor just wanted to see where our abnormality was. Both of us had almost the same abnormality which the tech doing the test described as "really odd that it would be almost identical". The results were not indicative of "Classic CF" which we already knew.
Jennifershope(?sp) I am so baffled by your situation. I don't understand why they don't just call it Atypical CF?? Culturing PA and MRSA is pretty much indicative of CF of some sort isn't it?? At least that's what I've read. I am so sorry you have to go through this. I hope you are still able to get all of the meds and tx's you need!!

amyr · May 14, 2011

Ihad the NPD done and so did one of my children. Their doctor just wanted to see where our abnormality was. Both of us had almost the same abnormality which the tech doing the test described as "really odd that it would be almost identical". The results were not indicative of "Classic CF" which we already knew.
Jennifershope(?sp) I am so baffled by your situation. I don't understand why they don't just call it Atypical CF??CulturingPA and MRSA is pretty much indicative of CF of some sort isn't it?? At least that's what I've read. I am so sorry you have to go through this. I hope you are still able toget all of the meds and tx's you need!!

amyr · May 14, 2011

Ihad the NPD done and so did one of my children. Their doctor just wanted to see where our abnormality was. Both of us had almost the same abnormality which the tech doing the test described as "really odd that it would be almost identical". The results were not indicative of "Classic CF" which we already knew.
Jennifershope(?sp) I am so baffled by your situation. I don't understand why they don't just call it Atypical CF??CulturingPA and MRSA is pretty much indicative of CF of some sort isn't it?? At least that's what I've read. I am so sorry you have to go through this. I hope you are still able toget all of the meds and tx's you need!!

JennifersHope · May 14, 2011

Karen the reason I was undiagnosed is because I do have symptoms, but my doctors do not feel they are consistent with CF, The second gene Q1330E is a gene that has never been described before, so basically, if they were to keep accurate records they could possible use my information should someone else test show this gene.

When a gene has never been described, it means it is not known if it is a disease causing gene or just a non disease causing gene, Simply right, I have disease? it should be disease causing.

I have an amazing CF doctor Dr Flume who now is my pulmonologist, I have been to UNC for the nasal PD and have also had Dr Nick at National Jewish Hospital review my records... All three are in agreement that my disease is not CF. I do have some specific lung damage but not the same type of lung damage that a CFer gets. I have severe asthma, reactive airway disease, and true vocal chord dysfunction, in addition to that, I am severely allergic to something in the environment, probably more then one thing.

Right now the life I live is good but I am extremely limited and where I can go and what I can do before I end up sick and more often then not lately intubated on life support.

Since I have limited my exposure, I stay out of stores, hospitals as much as possible, get a lot of rest, don't go near latex, rubber, and stay clear of a few other things, I do okay, minus chronic sinus infection.

My family is not comfortable with me just doing this and would like me to further pursue what it is wrong with me, I am currently on a break from tests and just relaxing,

Dr Nick at one point suggested that I may have my own version of CF since this gene has never been described before but he felt that it was highly unlikely.

It is very confusing to us all, imagine thinking you had CF for so many years, and then find out you don't.. It is so weird... I chose not to be in a relationship seriously and to not have children because I didn't want to pass on my genes.... Genes that may be perfectly safe.

I am most relieved that I don't have CF or so they say now, and I am going with that, I just pray in another 10 years they don't find something else out about the Nasal PD test and reverse my undiagnoses again.

IN the mean time I am being followed by the same doctor I would be anyway, he is great and I am comfortable with that.

I am not in any way shape of form a typical story, starting with the Addison's disease I have which causes false positives to being dx then undiagnosed, You can not base very much of anything on my case since no one knows anything, and for now i am supposed to live like the bubble boy and not expose myself to the world!!!

JennifersHope · May 14, 2011

Karen the reason I was undiagnosed is because I do have symptoms, but my doctors do not feel they are consistent with CF, The second gene Q1330E is a gene that has never been described before, so basically, if they were to keep accurate records they could possible use my information should someone else test show this gene.

When a gene has never been described, it means it is not known if it is a disease causing gene or just a non disease causing gene, Simply right, I have disease? it should be disease causing.

I have an amazing CF doctor Dr Flume who now is my pulmonologist, I have been to UNC for the nasal PD and have also had Dr Nick at National Jewish Hospital review my records... All three are in agreement that my disease is not CF. I do have some specific lung damage but not the same type of lung damage that a CFer gets. I have severe asthma, reactive airway disease, and true vocal chord dysfunction, in addition to that, I am severely allergic to something in the environment, probably more then one thing.

Right now the life I live is good but I am extremely limited and where I can go and what I can do before I end up sick and more often then not lately intubated on life support.

Since I have limited my exposure, I stay out of stores, hospitals as much as possible, get a lot of rest, don't go near latex, rubber, and stay clear of a few other things, I do okay, minus chronic sinus infection.

My family is not comfortable with me just doing this and would like me to further pursue what it is wrong with me, I am currently on a break from tests and just relaxing,

Dr Nick at one point suggested that I may have my own version of CF since this gene has never been described before but he felt that it was highly unlikely.

It is very confusing to us all, imagine thinking you had CF for so many years, and then find out you don't.. It is so weird... I chose not to be in a relationship seriously and to not have children because I didn't want to pass on my genes.... Genes that may be perfectly safe.

I am most relieved that I don't have CF or so they say now, and I am going with that, I just pray in another 10 years they don't find something else out about the Nasal PD test and reverse my undiagnoses again.

IN the mean time I am being followed by the same doctor I would be anyway, he is great and I am comfortable with that.

I am not in any way shape of form a typical story, starting with the Addison's disease I have which causes false positives to being dx then undiagnosed, You can not base very much of anything on my case since no one knows anything, and for now i am supposed to live like the bubble boy and not expose myself to the world!!!

JennifersHope · May 14, 2011

Karen the reason I was undiagnosed is because I do have symptoms, but my doctors do not feel they are consistent with CF, The second gene Q1330E is a gene that has never been described before, so basically, if they were to keep accurate records they could possible use my information should someone else test show this gene.
 
 When a gene has never been described, it means it is not known if it is a disease causing gene or just a non disease causing gene, Simply right, I have disease? it should be disease causing.
 
 I have an amazing CF doctor Dr Flume who now is my pulmonologist, I have been to UNC for the nasal PD and have also had Dr Nick at National Jewish Hospital review my records... All three are in agreement that my disease is not CF. I do have some specific lung damage but not the same type of lung damage that a CFer gets. I have severe asthma, reactive airway disease, and true vocal chord dysfunction, in addition to that, I am severely allergic to something in the environment, probably more then one thing.
 
 Right now the life I live is good but I am extremely limited and where I can go and what I can do before I end up sick and more often then not lately intubated on life support.
 
 Since I have limited my exposure, I stay out of stores, hospitals as much as possible, get a lot of rest, don't go near latex, rubber, and stay clear of a few other things, I do okay, minus chronic sinus infection.
 
 My family is not comfortable with me just doing this and would like me to further pursue what it is wrong with me, I am currently on a break from tests and just relaxing,
 
 Dr Nick at one point suggested that I may have my own version of CF since this gene has never been described before but he felt that it was highly unlikely.
 
 It is very confusing to us all, imagine thinking you had CF for so many years, and then find out you don't.. It is so weird... I chose not to be in a relationship seriously and to not have children because I didn't want to pass on my genes.... Genes that may be perfectly safe.
 
 I am most relieved that I don't have CF or so they say now, and I am going with that, I just pray in another 10 years they don't find something else out about the Nasal PD test and reverse my undiagnoses again.
 
 IN the mean time I am being followed by the same doctor I would be anyway, he is great and I am comfortable with that.
 
 I am not in any way shape of form a typical story, starting with the Addison's disease I have which causes false positives to being dx then undiagnosed, You can not base very much of anything on my case since no one knows anything, and for now i am supposed to live like the bubble boy and not expose myself to the world!!!

hmw · May 14, 2011

I personally feel it would be a good idea to have the NPD repeated considering you were not healthy when you had yours. Everything you can read online indicates that inflammation and irritation of the epithelial tissue can affect the results of the test significantly. I know, the dr you saw said differently than the CHOP dr re. how it affects the test- and the clinic you went to was involved in originating the test (though not the particular dr you saw- NPD testing has been around for quite some time even though not extremely widely used) - but it's worth a try. Accuracy in general is important no matter which way the results go! People repeat every other test for CF all the time, it may be worth considering the research trial being done at CHOP. They are working at getting NPD accepted in a more mainstream way as a diagnostic test... cases like yours require testing like this and seems ideal as an example. Anyway, mutations of unknown significance are determined whether or not to be disease causing by whether or not the people have them are symptomatic. I would hate to see future children who have this mutation denied an appropriate dx because needed repeat testing (i.e. sweat testing with your other condition being under control, a repeat NPD under more optimal circumstances) wasn't done and your case was not written up with ALL circumstances and/or caveats included. We see too much of that already. 'That mutation is non-disease-causing' with a kid exhibiting symptoms classic for CF... nothing more frustrating to read about, so I can only imagine what the parents feel like watching their kids endure it without appropriate, life-extending tx.
eta> I only feel this strongly about it because your case is not a typical one and not one that we should base our kids' experiences on... but the way your info goes into the cf registry and mutation database will affect FUTURE children with this mutation, so it's important to be as thorough as possible.

hmw · May 14, 2011

I personally feel it would be a good idea to have the NPD repeated considering you were not healthy when you had yours. Everything you can read online indicates that inflammation and irritation of the epithelial tissue can affect the results of the test significantly. I know, the dr you saw said differently than the CHOP dr re. how it affects the test- and the clinic you went to was involved in originating the test (though not the particular dr you saw- NPD testing has been around for quite some time even though not extremely widely used) - but it's worth a try. Accuracy in general is important no matter which way the results go! People repeat every other test for CF all the time, it may be worth considering the research trial being done at CHOP. They are working at getting NPD accepted in a more mainstream way as a diagnostic test... cases like yours require testing like this and seems ideal as an example. Anyway, mutations of unknown significance are determined whether or not to be disease causing by whether or not the people have them are symptomatic. I would hate to see future children who have this mutation denied an appropriate dx because needed repeat testing (i.e. sweat testing with your other condition being under control, a repeat NPD under more optimal circumstances) wasn't done and your case was not written up with ALL circumstances and/or caveats included. We see too much of that already. 'That mutation is non-disease-causing' with a kid exhibiting symptoms classic for CF... nothing more frustrating to read about, so I can only imagine what the parents feel like watching their kids endure it without appropriate, life-extending tx.
eta> I only feel this strongly about it because your case is not a typical one and not one that we should base our kids' experiences on... but the way your info goes into the cf registry and mutation database will affect FUTURE children with this mutation, so it's important to be as thorough as possible.

hmw · May 14, 2011

I personally feel it would be a good idea to have the NPD repeated considering you were not healthy when you had yours. Everything you can read online indicates that inflammation and irritation of the epithelial tissue can affect the results of the test significantly. I know, the dr you saw said differently than the CHOP dr re. how it affects the test- and the clinic you went to was involved in originating the test (though not the particular dr you saw- NPD testing has been around for quite some time even though not extremely widely used) - but it's worth a try. Accuracy in general is important no matter which way the results go! People repeat every other test for CF all the time, it may be worth considering the research trial being done at CHOP. They are working at getting NPD accepted in a more mainstream way as a diagnostic test... cases like yours require testing like this and seems ideal as an example. Anyway, mutations of unknown significance are determined whether or not to be disease causing by whether or not the people have them are symptomatic. I would hate to see future children who have this mutation denied an appropriate dx because needed repeat testing (i.e. sweat testing with your other condition being under control, a repeat NPD under more optimal circumstances) wasn't done and your case was not written up with ALL circumstances and/or caveats included. We see too much of that already. 'That mutation is non-disease-causing' with a kid exhibiting symptoms classic for CF... nothing more frustrating to read about, so I can only imagine what the parents feel like watching their kids endure it without appropriate, life-extending tx.
eta> I only feel this strongly about it because your case is not a typical one and not one that we should base our kids' experiences on... but the way your info goes into the cf registry and mutation database will affect FUTURE children with this mutation, so it's important to be as thorough as possible.

JennifersHope · May 14, 2011

Harriett, I agree with you. They actually have taken me out of the CFF registry, or so I was told. I was in it for a long time but when it was time to reenter the annual information, I believe that is when the removed me.

I totally understand where you are coming from and I certainly wouldn't want to make it harder for a child to be diagnosed with CF that truly has it. All of the doctors I talked to said the same thing, they have never seen a Nasal PD be negative and someone still have CF

UNC at first was going to draw my parents blood, and test them to help them define this gene further, because they don't know if it is on the same DNA strand if it was, then they would not know for sure if it was disease causing or not, if it wasn't then they said they could safely assume that it is a non disease causing variant. Either way for me it was not the cause of my problems.

I currently have had two negative sputum cultures...other then Pulmozyme and Tobi I am still doing all the other medications I would have for CF... inhalers, sinus rinses, zithromax daily.

I will do anything to help other families not have to go through this process that I am. I have to say though Harriett, when I was first diagnosed it was true denial for me.. I did not believe it or accept it.

Now, when I look at things objectively, stuff still does not add up, No one is saying I am healthy, Lord knows I have been sick my whole life, and have coughed my way through my entire school years, but I do not now nor have I ever really ever coughed anything up. I am Pancreatic Sufficient, I took enzymes for years because I was told I needed them, I have several diagnoses of DIOS with perforated bowels, and am scared from the bottom of my breast bone to my pubic bone from abdominal surgeries. All to find out, most likely it was not dios but the enzymes I was taking that I didn't need.

If I was to have one more culture of MRSA or PA, I would for sure be screaming for someone to do something for me... but how can I argue with three doctors, well two that actually reviewed my case and one that did the Nasal PD just did the test, that are highly experienced and in top of their field in CF???

I will email back to the doctors at UNC to see if they are going to follow through with my parents blood draws, since both my parents are now almost 70. I don't know what else to do. CF doctors are a tight knit group of people, and they will always refer back to each other, and basically not overstep each others toes.

My doctor I currently see is extremely respected in his field by all the other CF doctors and rightfully so. I have already been accused, not by my doctor, at least not to my face LOL but by others on the CF team when I questioned things that " I wanted to have CF so that is why I am questioning things" I was so pissed by that because I am the one who initiated every single test to prove I did not have CF, Including the Nasal PD and the full genetic testing... I didn't leave one stone unturned.

I guess I say all that to say, even though I am a nurse and I will fight a doctor toe to toe for my patients, when it comes to me, I feel like I don't want to be a pain, They have been very good to me, tolerating my millions of questions and stuff like that and really how can I argue with the top doctors in the field when all the evidence besides for a few things points away from CF?

JennifersHope · May 14, 2011

Harriett, I agree with you. They actually have taken me out of the CFF registry, or so I was told. I was in it for a long time but when it was time to reenter the annual information, I believe that is when the removed me.

I totally understand where you are coming from and I certainly wouldn't want to make it harder for a child to be diagnosed with CF that truly has it. All of the doctors I talked to said the same thing, they have never seen a Nasal PD be negative and someone still have CF

UNC at first was going to draw my parents blood, and test them to help them define this gene further, because they don't know if it is on the same DNA strand if it was, then they would not know for sure if it was disease causing or not, if it wasn't then they said they could safely assume that it is a non disease causing variant. Either way for me it was not the cause of my problems.

I currently have had two negative sputum cultures...other then Pulmozyme and Tobi I am still doing all the other medications I would have for CF... inhalers, sinus rinses, zithromax daily.

I will do anything to help other families not have to go through this process that I am. I have to say though Harriett, when I was first diagnosed it was true denial for me.. I did not believe it or accept it.

Now, when I look at things objectively, stuff still does not add up, No one is saying I am healthy, Lord knows I have been sick my whole life, and have coughed my way through my entire school years, but I do not now nor have I ever really ever coughed anything up. I am Pancreatic Sufficient, I took enzymes for years because I was told I needed them, I have several diagnoses of DIOS with perforated bowels, and am scared from the bottom of my breast bone to my pubic bone from abdominal surgeries. All to find out, most likely it was not dios but the enzymes I was taking that I didn't need.

If I was to have one more culture of MRSA or PA, I would for sure be screaming for someone to do something for me... but how can I argue with three doctors, well two that actually reviewed my case and one that did the Nasal PD just did the test, that are highly experienced and in top of their field in CF???

I will email back to the doctors at UNC to see if they are going to follow through with my parents blood draws, since both my parents are now almost 70. I don't know what else to do. CF doctors are a tight knit group of people, and they will always refer back to each other, and basically not overstep each others toes.

My doctor I currently see is extremely respected in his field by all the other CF doctors and rightfully so. I have already been accused, not by my doctor, at least not to my face LOL but by others on the CF team when I questioned things that " I wanted to have CF so that is why I am questioning things" I was so pissed by that because I am the one who initiated every single test to prove I did not have CF, Including the Nasal PD and the full genetic testing... I didn't leave one stone unturned.

I guess I say all that to say, even though I am a nurse and I will fight a doctor toe to toe for my patients, when it comes to me, I feel like I don't want to be a pain, They have been very good to me, tolerating my millions of questions and stuff like that and really how can I argue with the top doctors in the field when all the evidence besides for a few things points away from CF?

JennifersHope · May 14, 2011

Harriett, I agree with you. They actually have taken me out of the CFF registry, or so I was told. I was in it for a long time but when it was time to reenter the annual information, I believe that is when the removed me.
 
 I totally understand where you are coming from and I certainly wouldn't want to make it harder for a child to be diagnosed with CF that truly has it. All of the doctors I talked to said the same thing, they have never seen a Nasal PD be negative and someone still have CF
 
 UNC at first was going to draw my parents blood, and test them to help them define this gene further, because they don't know if it is on the same DNA strand if it was, then they would not know for sure if it was disease causing or not, if it wasn't then they said they could safely assume that it is a non disease causing variant. Either way for me it was not the cause of my problems.
 
 I currently have had two negative sputum cultures...other then Pulmozyme and Tobi I am still doing all the other medications I would have for CF... inhalers, sinus rinses, zithromax daily.
 
 I will do anything to help other families not have to go through this process that I am. I have to say though Harriett, when I was first diagnosed it was true denial for me.. I did not believe it or accept it.
 
 Now, when I look at things objectively, stuff still does not add up, No one is saying I am healthy, Lord knows I have been sick my whole life, and have coughed my way through my entire school years, but I do not now nor have I ever really ever coughed anything up. I am Pancreatic Sufficient, I took enzymes for years because I was told I needed them, I have several diagnoses of DIOS with perforated bowels, and am scared from the bottom of my breast bone to my pubic bone from abdominal surgeries. All to find out, most likely it was not dios but the enzymes I was taking that I didn't need.
 
 If I was to have one more culture of MRSA or PA, I would for sure be screaming for someone to do something for me... but how can I argue with three doctors, well two that actually reviewed my case and one that did the Nasal PD just did the test, that are highly experienced and in top of their field in CF???
 
 I will email back to the doctors at UNC to see if they are going to follow through with my parents blood draws, since both my parents are now almost 70. I don't know what else to do. CF doctors are a tight knit group of people, and they will always refer back to each other, and basically not overstep each others toes.
 
 My doctor I currently see is extremely respected in his field by all the other CF doctors and rightfully so. I have already been accused, not by my doctor, at least not to my face LOL but by others on the CF team when I questioned things that " I wanted to have CF so that is why I am questioning things" I was so pissed by that because I am the one who initiated every single test to prove I did not have CF, Including the Nasal PD and the full genetic testing... I didn't leave one stone unturned.
 
 I guess I say all that to say, even though I am a nurse and I will fight a doctor toe to toe for my patients, when it comes to me, I feel like I don't want to be a pain, They have been very good to me, tolerating my millions of questions and stuff like that and really how can I argue with the top doctors in the field when all the evidence besides for a few things points away from CF?

JennifersHope · May 14, 2011

Harriett, this was the response from Dr Donaldson.. about my sinus infection that I had when I had the nasal PD done.

Nasal inflammation can cause the nose not to respond normally even if the right channels are there. It wouldn't cause a falsely normal response. So, if your test was abnormal, we couldn't be sure it wasn't just from a cold and would have to repeat it. Because it was normal, this isn't a concern.

"false neg" and "false pos" can be confusing terminology - depends on whether you're looking for CF or normal.

So it think when the reports say a false negative it means it can make it look like I had CF when I didn't... because my nares were so swollen that they were not working properly. I think that is the confusion for us who are reading it online.....

I was told because my nose was swollen if the test came back positive they would have to re test me..

Does that help you understand?

JennifersHope · May 14, 2011

Harriett, this was the response from Dr Donaldson.. about my sinus infection that I had when I had the nasal PD done.

Nasal inflammation can cause the nose not to respond normally even if the right channels are there. It wouldn't cause a falsely normal response. So, if your test was abnormal, we couldn't be sure it wasn't just from a cold and would have to repeat it. Because it was normal, this isn't a concern.

"false neg" and "false pos" can be confusing terminology - depends on whether you're looking for CF or normal.

So it think when the reports say a false negative it means it can make it look like I had CF when I didn't... because my nares were so swollen that they were not working properly. I think that is the confusion for us who are reading it online.....

I was told because my nose was swollen if the test came back positive they would have to re test me..

Does that help you understand?

JennifersHope · May 14, 2011

Harriett, this was the response from Dr Donaldson.. about my sinus infection that I had when I had the nasal PD done.
 
 Nasal inflammation can cause the nose not to respond normally even if the right channels are there. It wouldn't cause a falsely normal response. So, if your test was abnormal, we couldn't be sure it wasn't just from a cold and would have to repeat it. Because it was normal, this isn't a concern.
 
 "false neg" and "false pos" can be confusing terminology - depends on whether you're looking for CF or normal.
 
 
 So it think when the reports say a false negative it means it can make it look like I had CF when I didn't... because my nares were so swollen that they were not working properly. I think that is the confusion for us who are reading it online.....
 
 I was told because my nose was swollen if the test came back positive they would have to re test me..
 
 Does that help you understand?

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