<<Disclaimer: Verify this information before applying it to your situation.>>
 
Q.  Should I just test endomysial antibodies or also do
gliadin/reticulin?
 
H.  Serological tests are performed at the time of diagnosis of celiac
disease and they are repeated later to estimate the efficacy of the
gluten-free diet.
 
It is recommended to perform a full serological test-panel in patients
with suspected celiac disease.  These tests measure antibodies belonging
to both the IgA and IgG classes of immunoglobulins.  The incidence of
selective IgA deficiency is much higher in celiac patients than in the
general population.  In patients with selective IgA deficiency only the
IgG antigliadin antibody may be present, however, this antibody is less
specific.  It means that the IgG-type antigliadin antibody may be
present in otherwise normal individuals.
 
If somebody had a positive endomysial antibody test at the time of
diagnosis he/she may choose to use only this antibody test to monitor
the effect of the diet.  There are individual differences in the
disappearance of serum antibodies.
 
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Q.  Is it important to use experienced laboratories for reliable test
results?
 
K.  Absolutely yes.  For the test to provide meaningful results, it must
be validated using a large number of clinical documented subjects.  In
addition, the two tests, endomysial and reticulin are immunofluorescent
tests where the readings are subjective.  Experienced laboratory
personnel are needed to read such tests.
 
H.  There are several advantages to use a laboratory experienced with
the celiac serological tests:
 
   -technically, the test are more reliable, and the internal and
external control of tests are better established than in laboratories
where the CD serology panel is only one of the routine tests
 
   -more importantly, laboratories specialized in celiac serological
testing have larger numbers of positive and negative samples to validate
their tests and they are able to set up more accurately the negative,
intermediate and pathologic values
 
   -a laboratory specialized in these tests generally has a clinical
background, and the physicians with experience in CD may help in the
interpretation of the results and they are happy to consult with other
physicians and they can answer the questions of patients.
 
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Q.  How can I convince my doctor to do these tests, and do them at an
experienced lab?
 
K.  Convincing the doctor initially depends upon the patient.  However,
the laboratory to which the test is sent should be available to answer
questions the doctor may have.  Our laboratory always encourages such
questions.
 
H.  Lot of physicians in the USA did not get appropriate training to
recognize the protean manifestations of celiac disease.  However, if the
classical symptoms are present--chronic diarrhea, weight loss,
protuberant abdomen, foul-smelling stools, etc.--it is absolutely
indicated to test the patients serum for antigliadin and antiendomysium
antibodies.
 
Professionals participating in this discussion group are educating
physicians on an almost daily basis.  Generally, it is useful to supply
the physician with a review article or a textbook chapter describing the
values of serological tests and protean manifestations of celiac
disease.  If that does not help, you can ask the help of professionals
participating in the Cel-Pro list.  They have helped several patients by
calling physicians and convincing them about the necessity of
serological testing.
 
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Q.  How often must a negative test be repeated in suspect individuals?
This question has two aspects:  for an individual with existing
symptoms, and for a sibling of a known celiac.
 
K.  If the test is negative and there is a strong suspicion of CD, it
must be repeated after several weeks (3-4 weeks), especially after a
high gluten intake.  We did a study of two cases with DH who were
serologically negative.  However, a gluten challenge 1g/Kg body wt/day
resulted in positive serology; the results became normal on a gluten
free diet.
 
If you are a relative of a CD patient and are on a regular diet and the
serology performed by an experienced laboratory is negative then there
may not be any need for retesting until and unless clinically justified.
 
H.  There is no rule for it.  If a family member with previous negative
tests experiences any gastrointestinal symptoms associated with CD,
he/she should undergo serological testing as soon as possible.  It is
well known that up to 15% of the family members of a patient with celiac
disease may have the asymptomatic (latent or silent) form of celiac
disease, although they have positive serological tests and have the
pathological changes in the upper part of the small intestine.  It is
also evident that there are at least three developmental stages of
mucosal lesions (Marsh MN. Gastroenterology 1992;102:330-354) and celiac
disease may manifest at each period of life.  That is why we recommend a
repeat test every 2-3 years in first degree relatives of celiac
patients.
 
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Q.  Suppose the biopsy or serum tests are inconclusive.  What do you do?
 
K.  The biopsy may be inconclusive.  Serum, if tested for gliadin,
endomysial and reticulin antibodies, should provide unequivocal
information.  Ours and other studies have provided a strong reliability
of the serum tests.
 
H.  The biopsy may be inconclusive in a small percentage of patients
with so-called patchy lesions in the duodenum.  It means that there are
histologically normal looking spots with finger like villi and
pathologic spots showing flattened mucosa in the upper half of the
duodenum.  If CD is suspected, the gastroenterologist should obtain
several biopsies from different spots of the whole duodenum.  Most of
the endoscopists routinely examine only the upper half of the duodenum
(duodenal bulb and the descending part).  The transverse segment of the
duodenum is not viewed routinely.  Few endoscopic centers have an
enteroscope, which is a longer and more flexible endoscope for examining
the entire duodenum and jejunum.  The enteroscopy allows you to obtain
biopsies even from the jejunum.  The histological examination of a
single biopsy specimen may increases the risk of false negative
diagnosis.
 
The experience of the pathologist in the interpretation of small
intestinal histology is important.  In centers specializing in celiac
disease the gastroenterologist routinely reviews the histologic slides
together with the pathologist.
 
There is still a possibility of inconclusive results if multiple
biopsies are obtained and the histological interpretation is
appropriate.  All disease has a developmental process.  It means that it
takes time for the pathological changes to be evident.  There are cases
when the symptoms suggest CD, however, the histology is not conclusive.
This problem occurs in only a few cases.  A repeated biopsy may be
necessary after a period of higher gluten intake.  However, if the
antiendomysium antibody test is positive and the histology is not
conclusive a gluten-free diet is recommended.
 
 The serology test may be inconclusive if:
 
   -the sample handling and shipping is inappropriate; e.g. the serum
was shipped at room temperature for days
 
   -the patient has IgA deficiency, which occurs in one out of 600
people in the general population and much more frequently in patients
with CD.  In these cases the antigliadin IgA and the antiendomysium IgA
tests give negative results.  If the tests are performed in a laboratory
specialized in celiac serological tests, the laboratory recommends a
test for immunoglobulins.  If a patient has IgA deficiency and positive
antigliadin IgG test, he/she should undergo further absorptive tests
and/or an intestinal biopsy.
 
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