<<Disclaimer: Verify this information before applying it to your situation.>>

I feel compelled to clarify the role of the intestinal biopsy in diagnosing
celiac disease, which is, in fact, the gold standard for diagnosis.
Hopefully one day soon we will have less invasive methods that yield even
better results. However, it is important for those with symptoms who are
seeking a diagnosis to know how important a biopsy is.

While celiac disease can be patchy, it is not in all cases. It has been
scientifically established that if a physician takes multiple samples
throughout the small intestine that a "sampling error" bias (choosing the
wrong sites to biopsy)can be avoided in a majority of cases. It is
perfectly acceptable for a patient to ask his or her physician how many
samples they plan to take during the procedure, and to request 6-8 if need
be.

Another question to ask the physician who will be performing the biopsy is:
how many have you done? Any procedure presents the small risk of potential
problems, and that is why antibody testing is performed, to determine who
would most benefit from the procedure, despite the small risk. The
physician scoping you or your child should have performed a high number of
biopsies prior to yours. This reduces the risk of potential problems during
the procedure.

It certainly is possible to have a pathologist who has not diagnosed celiac
disease and is not aware of the many subtleties that are present in a
biopsy sample with celiac. However, many pathologists consult one another
or experts in the field when analyzing a disease entity that is new to
them. In many cases (unfortunately) when a diagnosis has been years in the
making, changes in the intestinal wall are quite severe. In other cases,
the damage may be slight. In all cases, pathologists are not only looking
for damaged villi, but the presence of intraepithelial lymphocytes, a type
of cell that is the hallmark of celiac disease. This allows the pathologist
to differentiate the diagnosis of celiac disease from another disease that
affects the villi. It is possible to have one's pathology slides sent to a
more experienced laboratory for analysis, if there is a question about the
diagnosis.

It is important to remember that there are THREE steps to a celiac disease
diagnosis. The blood tests, the biopsy and a trial of the gluten free diet.
If the results of the biopsy are uncertain, a second opinion with a
physician at a major teaching hospital could be in order. In this
situation, the extent of symptoms often leads to a recommendation for a
trial of the gluten-free diet before determining that the patient doesn't
have it.

The problem with only having the blood tests but not the biopsy has to do
with the positive predictive value and the negative predictive value of the
antibody tests. The TTG and the anti-endomysial antibody tests are designed
to predict who DOES NOT have celiac disease with a very high rate of
reliability. This means that these tests have a high negative predictive
value. That is, when someone tests negative, we can be very comfortable
that the test result is accurate.

The same is not true for the positive predictive value of the tests, even
the ones that are highly sensitive and highly specific for celiac disease.
This leads to more false positive tests, allowing us only to conclude that
the positive individual needs a biopsy, not that he/she has celiac disease.
If those patients did not receive the endoscopy procedure to confirm the
diagnosis, they may be put on a gluten-free diet unnecessarily, and more
importantly, continue to suffer with symptoms and problems that are
incorrectly attributed to celiac disease and remain undiagnosed.

All of this being said, it is very pertinent to note that a significant
number of people in this country have not received a traditional diagnosis
of celiac disease due to the pervasive lack of knowledge within the health
care system about this condition. With few alternatives, and in the face of
great suffering, these individuals have taken their health in their hands
and learned about celiac disease on their own. And knowing the treatment
was dietary, these individuals embarked upon the diet and experienced a
rapid return to health. Am I saying that these individuals do not have
celiac disease? NO.

What I am saying that the best available science tells us that the gold
standard for diagnosis is the endoscopic biopsy, forgoing this aspect of
the diagnostic process has significant implications, and that the blood
tests currently available are not a substitute for the biopsy procedure.

There is certainly a choice for a patient to have or not have a biopsy,
based on individual circumstances. And it is only through evaluating
information about the procedures benefits and risks that an informed,
involved patient can determine what his best for him or her.

Michelle Melin-Rogovin
Program Director
University of Chicago Celiac Disease Program

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