Celiac disease, also known as gluten-sensitive enteropathy, is very common but often overlooked. It is an autoimmune disease of intestinal damage by gluten in genetically predisposed people. Classic celiac disease is diagnosed by abnormal blood tests and a
bowel showing up on biopsy and symptoms that resolve on a gluten-free diet.
There are several blood tests for celiac disease. They have different degrees of accuracy. Some are more sensitive, meaning they will be positive in milder forms of the disease, but are nonspecific, meaning a positive test may not indicate celiac disease. Others are considered very specific, meaning that when they are positive, you almost certainly have the disease.
The most specific tests are celiac disease endomysial antibody (EMA) tests and
tissue transglutaminase (tTG) antibody tests. Both of these tests are IgA-based tests and can be negative if you have IgA immunoglobin deficiency, which occurs in 10-20% of people with celiac disease. When EMA or tTG are positive, celiac disease is highly likely, and intestinal biopsy is usually positive. Recent studies indicate that tTG may only be positive in 40% of true celiacs when there are mild degrees of intestinal damage on biopsy. Seronegative celiac, meaning blood tests are negative but biopsy is positive, can occur in up to 20% of celiacs.
Antibodies against gliadin (AGA), the toxic fraction of gluten, are considered very sensitive but not specific for celiac disease. New AGA antibody assays for gluten that has undergone a chemical change
called deamidation appear to be more specific for celiac disease (Gliadin II,
Inova) than previous gliadin tests. They can also be as or more accurate than EMA and tTG
antibody tests, but they are not yet widely available.
The most distressing problem for people with minor forms of gluten intolerance who have blood tests and/or biopsies that are normal or borderline but respond to a gluten-free diet is that they are not taken seriously or are not known safely if they are sensitive to gluten. For these people stool
Anti-gliadin and tTG antibody tests have been helpful. These stool tests have been performed in research laboratories and have been published in a few studies, but have only recently become available through the commercial laboratory Enterolab. Founded by a former Baylor research gastroenterologist, Dr. Ken Fine, the tests are available to people online without a doctor’s order, but are not usually covered by insurance. Dr. Fine, who patented the test, has yet to publish the results of his findings in a peer-reviewed journal, so his tests are not widely accepted. However, his unpublished data and the clinical experience of some of us who have used his test have
indicated that the tests are very sensitive in detecting signs of gluten sensitivity. Reports that they are 100% sensitive for celiac disease and highly sensitive
for minor gluten sensitivity. In the presence of symptoms, which are reversed by a gluten-free diet,
In most people, abnormal levels of antibodies can be found in the stool before blood tests or biopsies are done.
abnormal.
Small bowel biopsies during upper gastrointestinal endoscopy
they are considered the “gold standard” for the diagnosis of celiac disease.
However, recent studies have shown that some people with gluten sensitivity, especially relatives of celiac
with few or no symptoms, has changes due to gluten injury to the intestine that cannot be seen with normal microscopic examination. They can only be seen with special stains that are not done routinely or with a research electron microscope. Special stains are known as immunohistochemical stains. They are stained in specialized white
blood cells called lymphocytes in the tips or villi of the intestinal lining. When these lymphocytes increase, it is known as intraepithelial lymphocytosis or increased IEL and is the earliest sign
of injuries or irritations induced by gluten. Electron microscopy also reveals very early ultrastructural changes in some individuals when blood tests and standard biopsy examination are normal. When people who have these changes are
offered the option of a gluten-free diet, they generally responded favorably. In contrast, those who continue to eat gluten often later develop classic celiac disease.
What these studies suggest is that a “normal small bowel biopsy” can exclude
Celiac disease is defined by strict criteria, but it is not a gold standard for screening for gluten sensitivity. This fact is appreciated by many people who have responded to a gluten-free diet starting
based on your symptoms, family history, suggestive blood tests, or antibodies in stool
tests).
Another source of confusion is in the genetics of celiac disease and gluten sensitivity.
Tests for specific blood type patterns in white blood cells known as HLA
DQ2 and DQ8 are increasingly being used to determine if a person carries either of the two genes.
pattern present in 95-98% of celiac patients and that predisposes them to the development of celiac disease. Some use the absence of these two patterns
as a way to exclude the possibility of celiac disease and the need for tests or
gluten free diet. However, there are rare reports of documented celiac disease in people who are DQ2 and
DQ8 negative. In addition, recent studies indicate other DQ
patterns may be associated with gluten sensitivity, although it is unlikely that
predisposes to classic celiac disease.
Dr. Fine recommends testing for all DQ patterns, based on their
Experience with stool antibody test results. He reports that other types of DQ are
associated with elevated levels of gliadin and tTG in stool and symptoms responsive to a gluten-free diet.
According to their unpublished data, all DQ types except DQ4 are associated with
a risk of gluten intolerance. Therefore, testing for all types of DQ allows a person
determine if they carry one of two types of high-risk genes for celiac disease, or
any of the other “minor DQ” genes that Fine has found to be associated with gluten sensitivity.
Enterolab stool test for gliadin antibodies and tissue
Transglutaminase antibodies, although not widely accepted, have gained favor with the laity
public opinion as an option for determining gluten sensitivity, either despite negative blood tests and/or biopsies or instead of more invasive testing. Most doctors still recommend the accepted and small blood tests
Intestinal biopsy to confirm celiac. Although reports in the lay community
are overwhelmingly positive that they have not been subjected to peer review in
the medical community waiting for Dr. Fine to publish his data or other researchers to reproduce his results.
However, doctors are open to
the broader gluten problem
sensitivity report that these tests are useful in many patients with suspected gluten
intolerance. Especially when someone has symptoms consistent with gluten sensitivity but has negative or inconclusive blood tests and/or biopsies, these tests can be very helpful, although some are not reliable.
how to interpret the evidence The national celiac organizations are not sure how
comment on your application without published research through a recent article
in the British Medical Journal showed highly specific stool tests for celiacs. dr
Fine has publicly commented that his unpublished data shows that those with
abnormal stool tests indicating gluten sensitivity
overwhelmingly respond favorably to a gluten-free diet with improved
symptoms and overall quality of life.
Another problem is that there are no universally agreed definitions for gluten sensitivity or intolerance. This becomes especially difficult for those who do not meet the strict criteria for celiac disease but who may have abnormal tests and/or symptoms that respond to a gluten-free diet. These people get confused when they try to find information but do not have a formal diagnosis of celiac disease. Much consensus is needed in the medical community on definitions and more research in this area.
The Few Doctors Who Appreciate the Spectrum of Gluten
intolerance or sensitivity are outnumbered by the medical majority who continue
insist on strict criteria for diagnosing celiac disease before recommending a
gluten free diet. Physicians who are unfamiliar with the limitations of the evidence documented by celiac research or who insist on
strict criteria for celiacs being the only indication to recommend a gluten-free product
Unfortunately, the diet can confuse or frustrate people who are sensitive to gluten. Some of these people then seek answers on the Internet or from alternative practitioners. Diagnosis is missed, questioned, dismissed or misinformed by many. As a result, they do not benefit from health.
benefits of a gluten-free diet because they are advised that it is not necessary based on normal blood tests and/or normal biopsies. Meanwhile, celiac disease and gluten sensitivity continue to go undiagnosed or misdiagnosed. For more information, visit http://www.thefooddoc.com.
