Post by kickingfrog on Feb 19, 2013 19:05:13 GMT
Gluten Challenge ( how much, how long?)
In patients being tested for coeliac disease using antibody tests, how long do they need to be on a gluten diet and what do they need to eat to ensure a valid test result?
18/Jun/07
Answer:
The CREST guideline on diagnosing and managing coeliac disease states:
“TGA and EmA can be used not only for diagnosis but also for monitoring of dietary compliance:
seroconversion occurs rapidly with strict gluten exclusion.
Conversely, if serology is to be meaningful in the diagnosis of coeliac disease patients must be taking a gluten containing diet for at least 3 months.”....
More detailed information on the amount plus lenght of time patients need to take gluten in their diet to provide an accurate diagnosis of coeliac disease is provided by the Coeliac Society:
“Two types of antibodies are tested for in the patient's serology; endomysial antibodies (EMA) and tissue transglutaminase antibodies (tTGA) which are produced in response to gluten ingestion.
Therefore it is essential that the patient has not removed gluten from their diet, and if they have it should be re-introduced for at least six weeks prior to blood being taken.
The amount of gluten that should be eaten depends largely on the patient, but as a rough guide an adult should aim to eat 4 slices of bread per day, or the equivalent amount of pasta, pizza base, biscuits etc.
Some research has shown that these blood tests are around 95% sensitive when performed in isolation, but when performed together are nearer to 99% accurate. However, other studies have suggested that the sensitivity is lower, nearer to 80%.
Although most seronegative results suggest coeliac disease is not present, it needs to be considered that patients with coeliac disease are more likely to be IgA deficient than the general population, so a seronegative result does not necessarily mean that the patient does not have coeliac disease and further investigations should be carried out in patients whose symptoms are strongly suggestive of coeliac disease.
A small bowel biopsy is still considered the gold standard for diagnosis of coeliac disease, so a referral to a gastroenterologist needs to be made in patient with positive antibodies and in those with negative antibodies but in whom CD is still suspected. ..” [2]
References
1. CREST. Guidelines for the diagnosis and management of coeliac disease in adults. May 2006.
2 Coeliac UK Diagnosis
************
Science Net
Coeliac volunteers on gluten-free diets were invited to eat four slices of gluten-containing bread daily for three days to activate the immune response against gluten.
Oxford University researchers from the Institute of Molecular Medicine and the Nuffield Department of Gastroenterology published the results of a study into the "toxic fraction" of gluten, which triggers coeliac disease, in the journal Nature Medicine.
******************************************
......................(by email from Professor Jewell)
........ The study was published in Nature Medicine in 2002 and you can find full details in the paper. However, the study very clearly showed that that short challenge was quite sufficient to demonstrate sensitivity to gluten in the coeliac patients. We were measuring the production of gamma interferon from T cells. I do not know your background so I am not sure whether you understand that. Anyway, this is a very sensitive immunological test. On the other hand, it is not the sort of thing that one can set up in any laboratory to test the occasional patient and is probably not practical for everyday clinical usage
Yours sincerely
Derek Jewell
Derek P Jewell
Professor of Gastroenterology & Consultant Physician
************************************************************
Gastroenterology Unit
University of Oxford
Gibson Laboratories (2nd Floor)
Radcliffe Infirmary
Woodstock Road
OXFORD OX2 6HE
United Kingdom
******************************************************
BMJ 2000;320:736 ( 18 March )
News extra
Coeliac disease specific antigen found
Abi Berger BMJ
..........Dr Anderson's team then took 12 patients with coeliac disease whose condition was stable on a gluten free diet and asked them to eat four slices of bread every day for three days.
Blood tests taken before and after the bread challenge showed that only two of the 51 gliadin peptides had stimulated an immune response. These two peptides overlapped each other, and seemed to require treatment with transglutaminase to be active. The specific lymphocytes that had been induced by these peptides appeared in the blood 6-8 days after the gluten challenge.
bmj.bmjjournals.com/cgi/content/full/320/7237/736/b
From St John's
How long do I need to eat gluten before getting the blood work and biopsy?
4 weeks of 4 slices of bread a day, or 4 weeks of 2 servings of pasta a day is thought to be enough stimulation. However, with a challenge there is a risk that the abnormalities will not be apparent.
Stephen Holland, M.D.
*************
Ensure adequate gluten intake prior to testing for CD
Therapeutic trials of Gluten Free Diet (GFD) are NOT indicated if coeliac
disease is suspected.
Children should not be started on a GFD on the basis of an antibody test.
•
At endoscopy, take 4 biopsies from D2 or lower (as patchy changes may be present)
•
Ensure adequate gluten intake prior to testing with advice from dietician if necessary. Typically,
10-15g gluten per day is required for adequate intake in most children (eg. 2-3g gluten are
contained in one medium bread slice, one Weetabix® or Shredded Wheat®, two rusks or
digestives and 4 tablespoons of cooked pasta)
bspghan.org.uk/
**********************
In patients being tested for coeliac disease using antibody tests, how long do they need to be on a gluten diet and what do they need to eat to ensure a valid test result?
18/Jun/07
Answer:
The CREST guideline on diagnosing and managing coeliac disease states:
“TGA and EmA can be used not only for diagnosis but also for monitoring of dietary compliance:
seroconversion occurs rapidly with strict gluten exclusion.
Conversely, if serology is to be meaningful in the diagnosis of coeliac disease patients must be taking a gluten containing diet for at least 3 months.”....
More detailed information on the amount plus lenght of time patients need to take gluten in their diet to provide an accurate diagnosis of coeliac disease is provided by the Coeliac Society:
“Two types of antibodies are tested for in the patient's serology; endomysial antibodies (EMA) and tissue transglutaminase antibodies (tTGA) which are produced in response to gluten ingestion.
Therefore it is essential that the patient has not removed gluten from their diet, and if they have it should be re-introduced for at least six weeks prior to blood being taken.
The amount of gluten that should be eaten depends largely on the patient, but as a rough guide an adult should aim to eat 4 slices of bread per day, or the equivalent amount of pasta, pizza base, biscuits etc.
Some research has shown that these blood tests are around 95% sensitive when performed in isolation, but when performed together are nearer to 99% accurate. However, other studies have suggested that the sensitivity is lower, nearer to 80%.
Although most seronegative results suggest coeliac disease is not present, it needs to be considered that patients with coeliac disease are more likely to be IgA deficient than the general population, so a seronegative result does not necessarily mean that the patient does not have coeliac disease and further investigations should be carried out in patients whose symptoms are strongly suggestive of coeliac disease.
A small bowel biopsy is still considered the gold standard for diagnosis of coeliac disease, so a referral to a gastroenterologist needs to be made in patient with positive antibodies and in those with negative antibodies but in whom CD is still suspected. ..” [2]
References
1. CREST. Guidelines for the diagnosis and management of coeliac disease in adults. May 2006.
2 Coeliac UK Diagnosis
************
Science Net
Coeliac volunteers on gluten-free diets were invited to eat four slices of gluten-containing bread daily for three days to activate the immune response against gluten.
Oxford University researchers from the Institute of Molecular Medicine and the Nuffield Department of Gastroenterology published the results of a study into the "toxic fraction" of gluten, which triggers coeliac disease, in the journal Nature Medicine.
******************************************
......................(by email from Professor Jewell)
........ The study was published in Nature Medicine in 2002 and you can find full details in the paper. However, the study very clearly showed that that short challenge was quite sufficient to demonstrate sensitivity to gluten in the coeliac patients. We were measuring the production of gamma interferon from T cells. I do not know your background so I am not sure whether you understand that. Anyway, this is a very sensitive immunological test. On the other hand, it is not the sort of thing that one can set up in any laboratory to test the occasional patient and is probably not practical for everyday clinical usage
Yours sincerely
Derek Jewell
Derek P Jewell
Professor of Gastroenterology & Consultant Physician
************************************************************
Gastroenterology Unit
University of Oxford
Gibson Laboratories (2nd Floor)
Radcliffe Infirmary
Woodstock Road
OXFORD OX2 6HE
United Kingdom
******************************************************
BMJ 2000;320:736 ( 18 March )
News extra
Coeliac disease specific antigen found
Abi Berger BMJ
..........Dr Anderson's team then took 12 patients with coeliac disease whose condition was stable on a gluten free diet and asked them to eat four slices of bread every day for three days.
Blood tests taken before and after the bread challenge showed that only two of the 51 gliadin peptides had stimulated an immune response. These two peptides overlapped each other, and seemed to require treatment with transglutaminase to be active. The specific lymphocytes that had been induced by these peptides appeared in the blood 6-8 days after the gluten challenge.
bmj.bmjjournals.com/cgi/content/full/320/7237/736/b
From St John's
How long do I need to eat gluten before getting the blood work and biopsy?
4 weeks of 4 slices of bread a day, or 4 weeks of 2 servings of pasta a day is thought to be enough stimulation. However, with a challenge there is a risk that the abnormalities will not be apparent.
Stephen Holland, M.D.
*************
Ensure adequate gluten intake prior to testing for CD
Therapeutic trials of Gluten Free Diet (GFD) are NOT indicated if coeliac
disease is suspected.
Children should not be started on a GFD on the basis of an antibody test.
•
At endoscopy, take 4 biopsies from D2 or lower (as patchy changes may be present)
•
Ensure adequate gluten intake prior to testing with advice from dietician if necessary. Typically,
10-15g gluten per day is required for adequate intake in most children (eg. 2-3g gluten are
contained in one medium bread slice, one Weetabix® or Shredded Wheat®, two rusks or
digestives and 4 tablespoons of cooked pasta)
bspghan.org.uk/
**********************