6 Key Steps in Celiac Disease Diagnosis

Overview

Celiac disease is an inflammatory disorder of the small bowel occurring in genetically susceptible individuals and it results from intolerance to the gluten component of the diet. Gluten is a protein found in wheat, rye and barley. Oats don't contain gluten but are often contaminated with it during processing. The disease can cause malabsorption and improves on a gluten-free diet. It occurs worldwide, affecting about 1 percent of people.

Many cases go undiagnosed, partly because some people have few or no symptoms. These include ‘silent’ cases. There are also ‘latent’ cases, in which people are genetically susceptible and may develop the disease later.

WHAT IS CELIAC DISEASE?

Celiac disease is an inflammatory disease that occurs in the small intestine. The people suffering from this disease have a genetic tendency to develop this disease and it occurs as a result of eating gluten, which is present in wheat, rye, barley and the many foods made from them. These immunological responses due to gluten play a key role in causing inflammation of Small intestinal mucosa and cause disease. First-degree relatives of people with celiac disease have a higher risk. Nearly everyone with the disease carries the HLA-DQ2 or HLA-DQ8 gene variants, although most people with these variants never develop it.

Major Celiac Disease Diagnosis

Celiac disease diagnosis starts with a physical examination and your medical history. The doctor may ask you about

the onset of disease
if the start was sudden in onset or gradual
he may ask about celiac disease Rash
Intestinal symptoms you face
change in stool frequency
change in stool consistency
if it occurs after eating wheat and it if it stops after eating rice

People with untreated celiac disease often have high levels of certain antibodies in their blood, such as anti-endomysial and anti-tissue transglutaminase antibodies. A simple blood test checks for them.

Keep eating gluten until testing is complete. NIDDK warns that a gluten-free diet can affect test results. Don't start a gluten-free diet until a specialist confirms the diagnosis.

1- Complete Blood Count:

A complete blood count (CBC) is a routine blood test that can show problems caused by celiac disease. A lab worker draws a blood sample from a vein, usually at the inside of the elbow. The needle may sting briefly, and any bruise heals within a few days.

A CBC does not detect celiac antibodies. Those need a separate antibody blood test, which can usually be done from the same blood draw.

A full blood count may also show anemia which may be microcytic anemia or macrocytic anemia. People may have iron or folate deficiency, which can show up as anemia on the blood count. There may be signs of hyposplenism which include target cells**,** spherocytes, and Howell Jolly bodies in samples of blood for disease diagnosis.

2- Small Intestinal Biopsy

Small intestinal biopsy is the gold standard test for celiac disease diagnosis. it is a confirmatory test for the diagnosis and is performed with the help of an endoscopic camera which is a thin flexible tube with a light at one end and camera at other ends. The endoscope is passed through your mouth and stomach into the first part of the small intestine (the duodenum), where small tissue samples are taken. Before the procedure, you usually get a numbing throat spray, a sedative, or both, to keep you comfortable.

Endoscopic appearance should not preclude biopsy as the mucosa may look normal. Damage can be patchy, so doctors usually take several biopsies, typically at least four from the second part of the duodenum plus one or two from the duodenal bulb. You may see the atrophy of intestinal Villi and hypertrophy of the crypts in the mucosa. Sometimes the intestinal wall will appear normal but there is a large number of intraepithelial lymphocytes which are called ‘lymphocytic duodenitis’.

3- Antibodies Detection

Antibody tests are screening tests for people with diarrhea or other suggestive symptoms. In adults, they usually don't replace a small intestinal biopsy. The two main antibodies tested are tissue transglutaminase and anti-endomysial antibodies.

If the antibody screen is positive, keep eating gluten until the duodenal biopsy, which confirms the diagnosis.

ANTIENDOMYSIAL ANTIBODIES (AEA) are detected by immunofluorescence in most untreated cases. This test is highly specific for celiac disease, meaning a positive result rarely occurs without it.
TISSUE TRANSGLUTAMINASE ANTIBODY (tTGA) assay is a screening test for celiac disease diagnosis. It is the test of choice in many countries because it is easy to perform and accurate. The standard version measures IgA antibodies, so it can give a false negative in people with IgA deficiency, which is more common in celiac disease.

For that reason, doctors often check total IgA at the same time. If IgA is low, they use IgG-based tests instead, such as deamidated gliadin peptide (DGP) antibodies.

4- Biochemical Tests

Other blood tests look for the effects of malabsorption, such as low levels of calcium, magnesium, iron, protein, albumin and vitamin D. A serum IgA measurement is also needed to make sure IgA-based antibody tests can be trusted.

5- DEXA Scan

A DEXA scan measures bone density. Celiac disease can weaken bones, so doctors may recommend a scan after diagnosis, especially for older adults and women after menopause. It checks for osteoporosis but doesn't diagnose celiac disease itself.

6- Evidence of Celiac Disease Rash

People with celiac disease may also have the celiac disease rash, called dermatitis herpetiformis, on their elbows, knees, back and buttocks. A skin biopsy of this itchy, blistering rash can help confirm the diagnosis.

HP Thoughts: Some people with celiac disease develop a skin rash. How would you cope? Read our next article to guide you: Celiac Disease Rash.

Conclusion

Celiac disease can be hard to diagnose in people without symptoms, but reliable screening and confirmatory tests are available. Keep eating gluten until testing is finished, because the tests are only accurate while gluten is in your diet.

If you think you may have celiac disease, talk to your doctor before changing your diet.