Celiac Disease Panel

The Celiac Disease Panel is a combined blood and stool testing package designed to support the initial laboratory assessment of suspected celiac disease and related intestinal inflammation. It includes total immunoglobulin A (total IgA), anti-tissue transglutaminase IgA (anti-tTG IgA), anti-tissue transglutaminase IgG (anti-tTG IgG), and fecal calprotectin.

Celiac disease is an immune-mediated condition in which gluten triggers damage to the lining of the small intestine in genetically susceptible people. Symptoms and laboratory findings vary considerably. Some people experience persistent digestive problems, while others are assessed because of anemia, nutrient deficiencies, autoimmune conditions, family history, or unexplained general symptoms. The panel can provide useful diagnostic direction, but it does not establish or exclude celiac disease on its own.

What the Celiac Disease Panel measures

• Anti-tTG IgA: The primary antibody test commonly used when celiac disease is suspected. Increased levels can support the need for further diagnostic evaluation.
• Total IgA: Helps determine whether the body produces enough IgA for the anti-tTG IgA result to be interpreted reliably. IgA deficiency can contribute to a falsely reassuring IgA-based result.
• Anti-tTG IgG: Provides additional information and can be particularly relevant when total IgA is low or deficient. The result must still be interpreted within the complete clinical picture.
• Fecal calprotectin: Measures a marker of inflammation in the intestine. It is not specific to celiac disease and cannot confirm the diagnosis, but it may help identify whether additional assessment for intestinal inflammation is appropriate.

When the panel may be considered

Testing may be considered when digestive symptoms are persistent, recurrent, or difficult to explain. Relevant concerns can include bloating after meals, abdominal pain and cramps after eating, prolonged or recurring diarrhea, unexplained constipation, or ongoing fatigue and low energy.

A clinician may also consider celiac testing for unexplained iron deficiency or anemia, reduced nutrient levels, unintentional weight loss, impaired growth in children, recurrent mouth ulcers, reduced bone density, abnormal liver tests, or a persistent itchy blistering rash. Testing may also be relevant for first-degree relatives of a person with celiac disease and for people with certain associated autoimmune or genetic conditions.

These findings are not specific to celiac disease. Similar symptoms can occur with food intolerances, irritable bowel syndrome, inflammatory bowel disease, infections, medication effects, thyroid disorders, and other digestive or systemic conditions. Laboratory results therefore need to be assessed together with symptoms, medical history, diet, and previous findings.

Do not remove gluten before testing

A person should not independently begin a gluten-free diet before celiac disease testing and diagnostic evaluation are complete. Reducing or eliminating gluten can lower antibody levels and make the blood results falsely negative or less conclusive, even when celiac disease is present.

Unless a doctor has given different instructions, the usual gluten-containing diet should generally be continued before blood testing. A person who has already reduced or eliminated gluten should tell the doctor before testing. Further planning may be needed, and gluten should not be reintroduced in large amounts without appropriate medical guidance if it previously caused significant symptoms.

How the Celiac Disease Panel is performed

Step 1: Review of symptoms and gluten intake

Before testing, it is useful to record current digestive and general symptoms, their duration, family history of celiac disease, previous laboratory findings, and whether gluten intake has recently changed. This information can substantially affect interpretation.

Step 2: Venous blood sampling

A venous blood sample is collected for total IgA, anti-tTG IgA, and anti-tTG IgG. Blood collection usually takes only a few minutes. Temporary discomfort, mild bruising, or lightheadedness can occur after venipuncture.

Step 3: Stool sample collection

A portion of stool is placed in a dedicated stool collection container for fecal calprotectin testing. The sample should not be contaminated with urine, toilet water, or cleaning products. Collection, storage, and transport instructions should be followed carefully because incorrect handling can affect sample quality.

Step 4: Laboratory analysis

The antibody tests and total IgA are measured from the blood sample, while calprotectin is measured from the stool sample. The report presents each result separately with the applicable laboratory reference range.

Step 5: Medical interpretation and next steps

The findings should be interpreted together rather than as isolated values. Antibody levels, total IgA, gluten intake, age, symptoms, family history, and previous testing can all influence the diagnostic pathway.

Key facts about the panel

• Samples: Venous blood and stool
• Included tests: Total IgA, anti-tTG IgA, anti-tTG IgG, and fecal calprotectin
• Main purpose: Initial laboratory assessment when celiac disease or intestinal inflammation is being considered
• Important preparation: Do not independently eliminate gluten before completing the diagnostic evaluation
• Limitation: The panel cannot independently provide a definitive celiac disease diagnosis

What the results may mean

Elevated anti-tTG antibodies can increase suspicion of celiac disease, particularly when the person is consuming gluten and the findings match the clinical picture. Total IgA helps determine how much confidence can be placed in the IgA-based antibody result. Anti-tTG IgG may contribute additional information when IgA production is reduced.

A normal antibody result does not always exclude celiac disease. Results can be less reliable when gluten has already been removed, when gluten intake is low, in cases of IgA deficiency, or in some early or less typical presentations. Further testing may still be appropriate when clinical suspicion remains significant.

Fecal calprotectin reflects intestinal inflammation but does not identify its cause. An increased result can occur with inflammatory bowel disease, gastrointestinal infection, medication effects, and other inflammatory conditions. It should not be interpreted as proof of celiac disease.

A positive or inconclusive result may require assessment by a gastroenterologist. Depending on age, antibody levels, symptoms, and applicable diagnostic criteria, further evaluation may include repeat serology, additional antibody testing, genetic testing, upper gastrointestinal endoscopy, and biopsies from the small intestine. A gluten-free diet should generally begin only after the diagnosis and further plan have been discussed with a qualified clinician.

Preparing an inquiry through ZagrebMed

Before sending an inquiry, prepare a short description of the symptoms, when they started, whether they are related to meals, any changes in bowel habits, weight, or energy, and whether gluten has already been reduced. Include previous blood tests, stool results, gastroenterology reports, endoscopy findings, information about autoimmune conditions, and relevant family history when available.

ZagrebMed can help organize the laboratory panel and clarify whether a gastroenterology consultation or another diagnostic step may be appropriate. Send an inquiry with the available medical information to receive guidance on the practical next step in Zagreb.