What is Celiac Disease?

  • An intestinal disease with wide spectrum of clinical manifestations, ranging from asymptomatic to  severe malabsorption, caused by a complex interplay of intrinsic and extrinsic factors:
    • Intrinsic factor is genetics imprinting the susceptibility of an individual to be gluten-sensitive in intestine
    • Extrinsic factor is the environmental factor, i.e., the presence of gluten
  • In genetically susceptible individuals, their intestines are characterized by damaged mucosa and hence many  secondary problems associated
  • Prolonged untreated celiac disease, even if clinically silent, predisposes for other autoimmune diseases

How Celiac Disease Affects Our Body?

Damages on the mucous layer of the small intestine by own immune system are often observed in celiac disease. The damages are most marked in the duodenum and upper jejunum, but in some cases, the entire small intestine may be involved.

Chronic diarrhea Failure to thrive Abdominal distention

In Accordance to a research paper published by American Gastroenterological Association in 2001, below are the symptoms that usually appear secondary to malabsorption of nutrients due to small intestine destruction. They are atypical because they only appear in Celiac Disease patients occasionally. Even if they do show up, they are usually considered to be medical conditions occurring alone and may often be ignored their possible correlations with Celiac Disease.

Systemically speaking, Celiac Disease has its impact on our body usually secondary to malabsorption due to destructions on the mucous layer of the small intestine.

Atypical Symptoms (Secondary to malabsorption)
Sideropenic anemia Short stature Osteopenia
Recurrent abortions Hepatic steatosis Recurrent abdominal pain

There are also a number of atypical symptoms independent of malabsorption.

Atypical Symptoms (Independent of maladsorption)
Dermatitis herpetiformis Dental enamel hypoplasia Ataxia
Alopecia Primary biliary cirrhosis Isolated hypertransaminasemia
Recurrent aphthous stomatitis  Myasthenia gravis  Recurrent pericarditis
Psoriasis Dental enamel hypoplasia Epilepsy (with or without intracranial calcifications)
Vasculitis Dilatative cardiomyopathy Hypo/Hyperthyroidism

Who will be affected?

Celiac disease symptoms can develop at any age when foods in your diet are containing gluten. Not only children, individuals aged between 30 and 60 years are determined as a group with high occurrence of having celiac disease.

High risk group: First-degree relatives of a person (parents, children, siblings) with celiac disease have around 10% chance of having this condition

Adults: Genetically susceptible adults who are consuming gluten, acute symptoms are sometimes triggered by stress, infections, surgery or pregnancy

Children: Recurrent gastrointestinal infections can be a factor in the expression of this disease

Typical symptoms like chronic diarrhea, failure to thrive and abdominal distention, are commonly seen in Celiac Disease patients. With these recurrent symptoms alone or in combination, one should consider taking the Celiac Screening

Who shall perform a blood test?

American Gastroenterological Association (AGA) recommends using serologic markers to screen patient with either non-specific symptoms or medical conditions that increase risk of celiac disease.

According to the guideline from the American College of Gastroenterology on the Diagnosis and Management of Celiac Disease, it is strongly recommended that:

*IgA anti-tissue tranglutaminase (tTG) antibody is the preferred single test for detection of CD in individuals over the age of 2 years.

*IgA- and IgG-based testing (such as IgG- & IgA-DGP) is strongly recommended when suspecting patients with CD and IgA deficiency.

*For young patients younger than 2 years of age for CD, the IgA-tTG should be combined with IgA- & IgG-DGP.

*In patients in whom low IgA or selective IgA deficiency is identified, IgG-based testing (IgG-DGP and IgG-tTG) should be performed.

What are gluten and gliadin ?

Gluten is a general name for the proteins found in wheat (varieties of wheat include: durum, emmer, spelt, farina, farro, kamut and einkorn), rye, barley and triticale.

Gliadin is one of the main protein component in gluten. The test is used to help find out whether you have celiac disease, an autoimmune disease by looking at the reaction to Gliadin.


Our Celiac Screening aims at measuring immune system response to tissue transglutaminase (tTG) and deamidated gliadin peptide (DGP) , thereby, to find out the influence of gliadin-containing foods in body.

Research studies have shown that the combination of tTG and DGP can detect nearly all biopsy proven celiac patients. These test items are suggested by studies as routine tests for celiac diseases.

The test requires 3-5ml of blood (1ml serum) only, take 2-3 weeks to get the report ready. It is a very convenient and much less invasive reduce the discomfort and lesions compared to upper endoscopy and intestinal biopsy.

Technology Competency

Reliable Technology that We Trust, Duplicate Runs for Ultimate Precision

  • Each sample will be test in duplicate as quality assurance
  • Chemiluminescent immunoassay (CIA) platform provides superior  sensitivity and specificity for celiac detection
  • Research studies have shown that the combination of tTG and DGP via CIA can detect nearly all biopsy proven celiac patients
  • CIA significantly increases the analytical measuring range, allowing the practitioner to monitor gluten-free diet compliance



Antigens Antibodies
Tissue transglutaminase (tTG) IgA-tTG




Deamidated gliadin peptide (DGP)



Before Deciding on a Gluten Free Diet

Gastroenterologist, Hong Kong
“This test covers almost everything I want to see when I suspect a patient may have celiac disease, before asking them going for a gluten free diet.”

IgG positive

Nutritionist, Hong Kong
“When patient is found to be IgG positive to wheat and suffering from celiac-like symptoms, I order this test to screen if the patient is a celiac. This is very helpful as the result tells if the patient needs to avoid gluten just a period of time or in the lifetime.”
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Just Gluten-Intolerant

Mr. JF, Hong Kong
“Going gluten-free is a trend in Hong Kong and USA. I do feel better after cutting gluten in my diet, yet I still want to confirm if I am a celiac, this’s why I ordered this test. The result has shown that I am just gluten-intolerant but not a celiac.”


Why testing for celiac?

1. What are the benefits of the Celiac Screening?

  • Report shows exact values for four markers (IgA-and IgG-tTG, IgA-and IgG-DGP) and a reference value will be provided.
  • A small amount of blood via blood drawing is required
  • Analysis completed in the U.S.
  • Comprehensive supporting information in client information sheets

2. Why shall I choose blood test for Celiac Disease?

Blood test is a very convenient way and much less invasive method, compared to upper endoscopy and intestinal biopsy. Using blood test can reduce the discomfort and lesions caused by these invasive methods. IgA-and IgG-tTG, IgA-and IgA-DGP tests constitute valuable diagnostic tools in the decision for more invasive intestinal biopsy. Also, they have proven their value of for the follow-up of CD and have revealed the high prevalence of undiagnosed CD. Therefore, scientific journals and medical organizations suggest that rather than ordering invasive testing, it is far better to start with serological testing on some reliable markers and follow up as necessary.

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3. Could we know more about the specificity and accuracy of the Celiac Screening?

HKBT Celiac Disease screening tests via blood. IgA and IgG against tTG (anti-tissue transgluaminase antibody), and IgA and IgG against DGP (anti-deamidated gliadin peptide antibody) levels in blood are assessed by Chemiluminescent Immunosorbent Assays (CIA).The results indicate either positive or negative in each analyte. In combination with other clinical observations, they provide you and healthcare professionals some reference data so as to find out more about your condition. A diet change that eliminates gluten-containing foods can result in total recovery of damaged intestine of individuals diagnosed with celiac disease.

Samples will be sent to US Biotek Labs for analysis. Each sample will be test in duplicate as quality assurance. US BioTek Labs has been accredited by COLA. Its Latest technology with the highest sensitivity and it is the only lab giving reproducible results.



1. How do I go about the Celiac Screening?

Contact us to make an appointment and we will arrange blood drawing at the nearby medical lab for you.

Office Hours:
10am-7pm (Mon-Fri);
9am-5pm (Sat)
Closed on Sun & Public Holidays

We will send your sample direct to the US lab for testing. You will receive the results within 10 – 20 days.

2. How much blood is needed for the Celiac Screening?

3-5ml blood.

3. Is Celiac Screening a diagnosis?

Celiac Screening consists of tests on IgA-and IgG-tTG, IgA-and IgA-DGP, which in combination are considered to be a very reliable primary screening tool for Celiac Disease, even though it cannot replace any diagnosis made by medical doctor.

4. Why does the Celiac Screening test ‘IgG-tTG and IgA-tTG’?

In celiac disease, the body produces antibodies that attack tTG. IgA antibody is made in the small intestine where gliadin causes inflammation irritation in sensitive people. By measuring the IgA antibodies in blood, we investigate our body’s response to gliadin which is useful in detecting celiac disease.

5. Why does the Celiac Screening test IgA and IgG against DGP?

Celiac disease can be screened by serological test as serological antibodies support the diagnosis of celiac disease and act as an important role in the screening and follow-up process. tTG antibodies is very sensitive and specific , is thus a primary screening tool for celiac disease. IgA anti-tTG antibodies monitor gluten-free dietary compliance and its treatment effect. Yet, IgA anti-tTG antibodies may give false negative result of celiac disease patient with low total serum IgA levls. Determination of IgA anti-tTG combined with IgG-based testing (IgG-DGP and IgG anti-tTG) is therefore usually recommended.

A meta-analysis revealed the diagnostic accuracy of DGP and tTG for celiac disease in sensitivity is 87.8% (95% CI: 85.6%~89.9%) and 93% (95% CI: 91.2%~94.5%), while in specificity is 94.1% (95% CI: 92.5%~95.5%) and 96.5% (95% CI:95.2%~97.5%), respectively. tTG is therefore the primary screening tool as it shows higher value in predicting celiac diseases than that of DGP. Testing on IgA-/ IgG- and tTG/DGP could be used to obviate the need for determine total serum IgA levels in suspecting patients since the sensitivity and specificity of these four serologic test is 98.6% and 100%, respectively, in which sensitivity performs better than in testing IgA -tTG alone.



1. Is the Celiac Screening suitable for all ages?

Adults and children can take the test. In general, infants after 6 months start weaning and eating solid foods, probably containing gluten. Thus, kids age after 6 months and starting eating solid gluten-containing foods can take the test.

2. Do I need a doctor’s prescription to have the Celiac Screening done?

In general, any individual can order any tests for your health information. A doctor’s prescription is not required.

3. Can I have this test done if I am taking Chinese or Western medicine?

You may please consult your practitioner if you have any questions concerning your Chinese medicine. In general, the major concern is steroidal drugs, e.g. cortisone, because it can suppress the immune system, and thus may reduce the antibodies present, causing a “false negative” report. Thus it is advisable to stop taking the steroidal drug for at least 3 weeks before taking the test. Tropical steroid is not part of the concerns.



1. What information will the Celiac Screening report provide?

Celiac Screening result would be shown as values of different analytes and reference value for each analyte is provided. Elevated serology is recognized in untreated celiac disease patients. Repeat testing may be used to assess response to treatment. Persistently elevated antibody levels may suggest lack of adherence to a gluten-free diet.

2. What do I have to be aware of after I get my test results?

All of the markers are recognized to be of over 90%accuracy and specificity internationally. But these IgA based parameters may be compromised in IgA-deficient individuals, individuals with karyotype abnormalities or with diabetes and children under three years of age. IgG-based result become very useful in such case. If anyone with a negative test result and symptoms suggestive of Celiac Disease, they should visit physicians and consider an upper endoscopy and intestinal biopsy.

3. What if I have been following a gluten-free diet?

For all diagnostic tests for Celiac Disease test to work properly, one must eat gluten daily. If you have avoided gluten for a long period of time, there may be false negative results in all diagnostic methods for Celiac Disease. Some physicians recommend patients be on a gluten containing diet for 2-4 weeks before serologic testing.

4. Can I overgrow Celiac Disease?

There is no scientific evidence that anyone can outgrow celiac disease once he/she is diagnosed with CD because it is a genetic disease. Hence, the genetically predisposed individuals will develop symptoms every time when they eat gluten-containing foods, even though there are asymptomatic CD patients, whereas, all symptoms and damages of their bodies will be fully recovered when they avoid gluten for a certain period of time. Therefore, the CD patients are recommended to avoid gluten once they are diagnosed.