Emily saw a GI dr. and was tested for celiac disease shortly before being dx'ed with CF. Her panel was overwhelmingly negative. However, as mentioned, the labs are not always reliable- though this can go both ways- false negatives (esp when done with young children, whose immune systems are immature) as well as false positives (for example, when everything is normal except for an elevated antigliadin IgG, which can be caused by multple other conditions, including CF.) We were told the TTG results (Tissue transglutaminase antibodies) were the most accurate values of the panel but even they can be falsely positive if another condition is present. So frustrating!
CF and Celiac disease are similar in that they can both be largely asymptomatic for years, and start doing damage without even realizing it, so an accurate dx is important so you can start appropriate treatment.
<div class="FTQUOTE"><begin quote>Can CF cause a false positive on the celiac antibody blood test?</end quote></div>
In a word, yes...
There is some good info in this article detailing all of the tests in the celiac panel; here is an excerpt with information about one of them.
<a target=_blank class=ftalternatingbarlinklarge href="http://americanceliac.org/diagnosis.htm">American Celiac Disease Alliance: Diagnosis</a>
<div class="FTQUOTE"><begin quote><b>Antigliadin antibodies</b>
The antigliadin antibodies IgG and IgA recognize a small piece of the gluten protein called gliadin. These antibodies became available during the late 1970's and were the first step towards recognizing CELIAC DISEASE as an autoimmune disorder. Antigliadin IgG has good sensitivity, while antigliadin IgA has good specificity, and therefore their combined use provided the first reliable screening test for CELIAC DISEASE. Unfortunately, many normal individuals without CELIAC DISEASE will have an elevated antigliadin IgG, causing much confusion among physicians. The antigliadin IgG is useful in screening individuals who are IgA deficient, as the other antibodies used for routine screening are usually of the IgA class. It is thought that 0.2-0.4% of the general population has selective IgA deficiency, while 2 to 3% or more of celiacs are IgA deficient.
If a patient's celiac panel is only positive for antigliadin IgG, this is not highly suggestive for CELIAC DISEASE if the patient has a normal total IgA level, corrected for age. Younger children make less IgA than older children and adults. A markedly elevated antigliadin IgG, such as greater than three to four times the upper limit of normal for that lab, is highly suggestive of a condition where the gut is leakier to gluten. This can happen in food allergies, cystic fibrosis, parasitic infections, Crohn's disease, and other types of autoimmune GI diseases. These antibodies may also be slightly elevated in individuals with no obvious disease.</end quote></div>
I agree with the others that genetic testing for CF is important, and would also like to add that if an upper GI & biopsy is scheduled to further investigate a celiac dx- DON'T start her on a gluten-free diet until after this is completed, since this can affect the accuracy of the results. There is also a test to determine if she carries the celiac gene, as Heather mentioned. I wonder if this could be ordered for your dd.
CF and Celiac disease are similar in that they can both be largely asymptomatic for years, and start doing damage without even realizing it, so an accurate dx is important so you can start appropriate treatment.
<div class="FTQUOTE"><begin quote>Can CF cause a false positive on the celiac antibody blood test?</end quote></div>
In a word, yes...
There is some good info in this article detailing all of the tests in the celiac panel; here is an excerpt with information about one of them.
<a target=_blank class=ftalternatingbarlinklarge href="http://americanceliac.org/diagnosis.htm">American Celiac Disease Alliance: Diagnosis</a>
<div class="FTQUOTE"><begin quote><b>Antigliadin antibodies</b>
The antigliadin antibodies IgG and IgA recognize a small piece of the gluten protein called gliadin. These antibodies became available during the late 1970's and were the first step towards recognizing CELIAC DISEASE as an autoimmune disorder. Antigliadin IgG has good sensitivity, while antigliadin IgA has good specificity, and therefore their combined use provided the first reliable screening test for CELIAC DISEASE. Unfortunately, many normal individuals without CELIAC DISEASE will have an elevated antigliadin IgG, causing much confusion among physicians. The antigliadin IgG is useful in screening individuals who are IgA deficient, as the other antibodies used for routine screening are usually of the IgA class. It is thought that 0.2-0.4% of the general population has selective IgA deficiency, while 2 to 3% or more of celiacs are IgA deficient.
If a patient's celiac panel is only positive for antigliadin IgG, this is not highly suggestive for CELIAC DISEASE if the patient has a normal total IgA level, corrected for age. Younger children make less IgA than older children and adults. A markedly elevated antigliadin IgG, such as greater than three to four times the upper limit of normal for that lab, is highly suggestive of a condition where the gut is leakier to gluten. This can happen in food allergies, cystic fibrosis, parasitic infections, Crohn's disease, and other types of autoimmune GI diseases. These antibodies may also be slightly elevated in individuals with no obvious disease.</end quote></div>
I agree with the others that genetic testing for CF is important, and would also like to add that if an upper GI & biopsy is scheduled to further investigate a celiac dx- DON'T start her on a gluten-free diet until after this is completed, since this can affect the accuracy of the results. There is also a test to determine if she carries the celiac gene, as Heather mentioned. I wonder if this could be ordered for your dd.