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.
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. 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.
REPORT & AFTER-TESTING
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.