Diagnosing Celiac Disease and Gluten Sensitivity

Celiac disease, also known as gluten sensitivethese changes areoffered the option of a
enteropathy is very common but frequentlygluten-free diet they usually responded favorably.
missed. It is an autoimmune disease of intestinalIn contrast, those who continue to eat gluten
damage due to gluten in people who areoften later developed classic Celiac disease.
genetically predisposed. Classic Celiac disease isWhat these studies suggest is that a "normal
diagnosed by abnormal blood tests and ansmall intestine biopsy" may exclude
abnormalappearing intestine on biopsy andCeliac disease as defined by strict criteria but it is
symptoms that resolve with a gluten free diet.not a gold standard for detecting gluten sensitivity.
Several blood tests exist for Celiac disease. TheyThis fact is appreciated by many individuals who
have varying degrees of accuracy. Some arehave respond to a gluten-free diet they
more sensitive, meaning they will be positive instartbased on their symptoms, family history,
milder forms of the disease but are not specific,suggestive blood test or stool antibodytest(s).
meaning a positive test may not indicate CeliacAnother source of confusion is in the genetics of
disease. Others are felt to be very specific,Celiac and gluten sensitivity.
meaning that when they are positive, it is almostTesting for specific blood type patterns on white
certain you have the disease.blood cells known as HLA
The most specific tests are tests for CeliacDQ2 and DQ8 is increasingly being employed to
disease endomysial antibodies (EMA) andtissuedetermine if a person carries either of the two
transglutaminase antibody (tTG) tests. These twogenepattern present in 95-98% of Celiacs and
tests are IgA based tests and can be negative ifpredisposing them to the development of Celiac
you are deficient in the immunoglobin IgA, whichdisease. Some use the absence of these two
occurs in 10-20% of people with Celiac. Whenpatternsas a way of excluding the possibility of
either EMA or tTG are positive Celiac disease isCeliac disease and the need for testing
very likely and usually the intestine biopsy isorgluten-free diet. However, there are rare
positive. Recent studies indicate that the tTG mayreports of documented Celiac disease in people
only be positive in 40% of true Celiacs when mildwho are DQ2 and
degrees of intestine damage are present onDQ8 negative. Moreover, recent studies indicate
biopsy. Seronegative Celiac, meaning the bloodother DQpatterns may be associated with gluten
tests are negative but the biopsy is positive, maysensitivity though unlikely topredispose to classic
occur in up to 20% of Celiacs.Celiac disease.
Antibodies for gliadin (AGA), the toxic fraction ofTesting for all the DQ patterns is advocated by
gluten are considered very sensitive but notDr. Fine, based on hisexperience with stool
specific for Celiac disease. Newer assays for AGAantibody test results. He reports that other DQ
antibodies for gluten that has undergone atypes areassociated with elevated levels of gliadin
chemical changecalled deamidation appear to beand tTG in the stool and symptoms that respond
more specific for Celiac disease (Gliadin II,to a gluten-free diet.
Inova) than the older gliadin tests. They also mayAccording to his unpublished data, all the DQ types
be as or more accurate than EMA andexcept DQ4 are associated witha risk of
tTGantibody tests but are not yet widelyintolerance to gluten. Therefore, testing for all the
available.DQ types allows a person todetermine if they
The most distressing problem for people withcarry one of the two high risk gene types for
lesser forms of gluten intolerance who have bloodCeliac disease orany of the other "minor DQ"
tests and/or biopsies that are normal or borderlinegenes Fine has found associated with gluten
yet respond to a gluten free diet is either notsensitivity.
being taken seriously or knowing for sure if theyEnterolab's stool testing for gliadin antibodies and
are sensitive to gluten. For these individualstissuetransglutaminase antibodies, though not
stoolantibody testing for antigliadin and tTG havewidely accepted, have gained favor in the
been helpful. Such stool testing has beenlaypublic's opinion as an option for determining
performed in research labs and published in a fewsensitivity to gluten either despite negative blood
studies but are only recently available through thetests and/or biopsies or in place of the more
commercial lab, Enterolab. Founded by a formerinvasive tests. Most doctors still recommend the
Baylor research gastroenterologist, Dr Ken Fine,accepted blood tests and smallbowel biopsy for
the tests are available to people online without aconfirmation of Celiac. Though the reports in the
doctors order but are not generally covered bylay communityare overwhelmingly positive they
insurance. Dr. Fine, who patented the test, hashave not been subjected to peer review inthe
yet to publish the results of his findings in a peermedical community pending Dr. Fine publishing his
reviewed journal so his tests are not widelydata or other researchers reproducing his results.
accepted. However, his unpublished data and theHowever, doctors open tothe broader problem of
clinical experience of some of us who have usedglutensensitivity are reporting these tests helpful in
his test haveindicated the tests are very sensitivemany patients suspected of glutenintolerance.
for signs of gluten sensitivity. He reports thatEspecially when someone has symptoms
they are 100% sensitive for Celiac disease andconsistent with gluten sensitivity but has negative
highly sensitivefor gluten sensitivity of lesseror inconclusive blood tests and/or biopsies these
degrees. In the presence of symptoms, thattests may be very helpful though some are not
reverse on a gluten-free diet,abnormal stoolcertainhow to interpret the tests. The national
antibody levels can be found in most peopleCeliac organizations are uncertain about how
before blood tests or biopsies becomeabnormal.tocomment on their application without published
Small intestine biopsies during upperresearch though a recent articlein the British
gastrointestinal endoscopyare considered the "goldMedical Journal did show stool tests highly specific
standard" for the diagnosis of Celiac disease.for Celiac. Dr.
However, recent studies have demonstrated thatFine has publicly commented that his unpublished
some people with gluten sensitivity, especiallydata demonstrates those withabnormal stool
relatives of Celiacswith little or no symptoms,tests indicating gluten sensitivityoverwhelmingly
have changes from gluten injury to the intestinerespond favorably to a gluten free diet with
that can not be seen with normal microscopeimprovement ofsymptoms and general quality of
examination. They can only be seen with speciallife.
stains not routinely done or with a researchAnother problem is that there are not universally
electron microscope. The special stains are knownagreed upon definitions for gluten sensitivity or
as immunohistochemistry stains. They stainintolerance. This becomes especially difficult for
specialized whiteblood cells called lymphocytes inthose who do not meet strict criteria for Celiac
the intestinal lining tips or villi. When thesedisease yet may have abnormal tests and/or
lymphocytes are increased it is known assymptoms that respond to a gluten-free diet.
intraepithelial lymphocytosis or increased IELs andThose individuals become confused when they try
it is the earliest signof gluten induced injury orto find information but do not have a formal
irritation. Electron microscopy also reveals verydiagnosis of Celiac disease. Consensus in the
early ultrastructural changes in some individualsmedical community on definitions and more
when blood tests and standard biopsyresearch in this area is greatly needed.
examination are normal. When people who have