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        I would like to add what little I know about antibody testing in
regards to diagnosis and follow up of celiac sprue. As an introduction, I
would like to say that I am a medical technologist and specialist in
blood banking. While I am no expert in laboratory testing, except in the
blood bank, I have a bit more experience and exposure to testing than the
average person. I have also talked some to the pathologist in charge of
the laboratory where I work in regards to these tests.
        The test for anti-gliadin antibodies (IgG and IgA) are poor
predictors of celiac sprue because they have a high rate of false
positives. That is, many of the positive test results should have really
been negative. To quote the write-up in our laboratory manual
"Anit-gliadin antibodies may sometimes persist during inactive celiac
disease or dermatitis herpetiformis when more specific but less sensitive
IgA antibodies are often absent. Gliadin antibodies are poorly specific,
being found in about 20% of otherwide normal children and up to 40% of
normal adults. IgA endomysial antibodies appear to be much more
spparticularly when the patient is in remission on a low gluten diet."
        It is unknown if the false positives are from people with latent
celiac disease, in which case they could be considered true positives.
        The write up for endomysial antibody is as follows: "Unlike
poorly-specified anti-gliadin antibodies, IgA anti-endomysial antibodies
are alleged to be specific as well as more sensitive for the active
gluten sensitive enteropathy of celiac disease and dermatitis
herpetiformis. In the unusual gluten sensitive patient with IgA
deficiency, IgG class antibodies, which are usually low or absent in
fluten sensitive patients with normal IgA levels, are elevated in
apparent compensation for the lack of IgA antibodies. The titers of
anti-endomysial antibodies decrease markedly in inactive cases on a
strick gluten free diet for over 1 year."
        It appears that the gold standard for diagnosing celiac sprue is
the finding of flattened mucosal on a duodenal biopsy and a positive
response to a gluten free diet, except in the few, rare cases of
refractory celiac sprue in which there is not a positive response to the
diet.
        My diagnosis story started with the usual lab tests for diarrhea,
stool cultures and looking for ova and parasites, with nothing unusual
found. At my husbands' insistance, I asked to be treated for giardia, but
there was still no improvement. I was tested for various chemistries,
mostly protein and albumin to see if I has malabsorption. All results
were in normal range. Then a sigmoidoscopy, which was normal. Finally I
had a barium GI series and that was abnormal and gave an indication of
malabsorption. I then had the duodenal biopsy which came back with
flattened mucosal finding. For some reason, my GI specialist really
wanted to clince the diagnosis and had me do a 72 hour stool sample for
fat (a truely enlightening experience if ever I had one) and a d-xylose
to prove malabsorption.
        I was told that the vast majority of cases of malabsorption are
cause by gluten and was told to go on a gluten free diet. Symptoms then
disappeared. I had previously tried a lactose free diet before my
diagnosis and that certainly did cut down my symptoms. Now that I can
have lactose without any symptoms, I believe that my lactose sensitivity
was temporarily induced from all the irritation of my gluten sensitivity.
        Anyway, that's enough rambling from me. While I must admit that
inconvience of this diet is sometimes annoying, as you need to be
constantly planning ahead for food instead of driving to the pizza place
for a pizza, I would much rather be on this diet and be symptom free than
to be off of it and spent my nights in pain and my days on the toilet.
        Ellen Eagan
        South San Francisco