Guidelines for diagnosing coeliac disease are rapidly evolving, as sensitive and specific laboratory assays are now available as part of the coeliac disease diagnostic algorithm. Though biopsy is still recommended as a gold standard by many gastroenterologists1, biopsies may still be inconclusive.2 Therefore, in many cases it may be possible to diagnose coeliac easily and quickly via a few essential blood tests. These include immunoglobulins produced against tissue transglutaminase (tTG) and deamidated gliadin peptide (DGP). If these markers are found elevated in genetically predisposed people who are consuming a gluten-containing diet and present with symptoms of coeliac disease, a diagnosis of coeliac disease is strongly supported.3 After further genetic testing to identify the histocompatibility leukocyte antigens (HLA) haplotypes associated with coeliac disease, namely HLA-DQ2/ DQ8, a diagnosis may be made with confidence.
Doctor’s Data, a clinical laboratory providing specialty tests since 1972, has now successfully validated procedures for using fingerstick blood for the key markers that identify coeliac disease and gluten sensitivity, as well as aiding in monitoring the effectiveness of therapies. Now, with a few drops of blood from a fingerstick, Doctor’s Data is able to detect and quantify immunologic markers formed against gliadin and DGP using the QUANTA Lite and QUANTA Flash assays from Inova Diagnostics. Following extensive method validation protocols, the Doctor’s Data team has confirmed that analyzing eluted blood spots are equivalent in sensitivity and specificity to testing serum for these immunologic markers of coeliac disease and gluten sensitivity.4
Massachusetts General Hospital has teamed with Doctor’s Data to investigate the utility of dried blood spot testing for screening newborns and infants of parents who have tested positive or have been genetically determined to be at an increased risk for these conditions. In initial screening comparisons, Doctors Data results have demonstrated 100% functional concordance with MGH traditional serology.
It should be noted, however, that sometimes IgA serology, whether blood test or pinprick is negative, if total IgA is low. A negative serology should be followed by testing total IgA and total IgG. If they are low, further testing or biopsy may be required, or HLA DQ2/D8 genetic testing with subtypes may be warranted; if HLA DQ2/DQ8 testing is negative, coeliac disease is excluded.5
- Ludvigsson JF, Bai JC, Biagi F, Card TR, Ciacci C, Ciclitira PJ, Green PH, Hadjivassiliou M, Holdoway A, van Heel DA, Kaukinen K, Leffler DA, Leonard JN, Lundin KE, McGough N, Davidson M, Murray JA, Swift GL, Walker MM, Zingone F, Sanders DS. Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology. British Society of Gastroenterology. Gut. 2014 Aug;63(8):1210-28. PMID: 24917550 View Abstract
- The University of Chicago Coeliac Disease Center. Are biopsies of the small intestine conclusive? http://www.curecoeliacdisease.org/archives/faq/is-a-biopsy-of-the-small-intestine-conclusive. Accessed 21 Oct 2015.
- Rubio-Tapia A, Hill ID, Kelly CP, et al. ACG clinical guidelines: diagnosis and management of coeliac disease. Am J Gastroenterol. 2013;108(5):656-76. PMID: 3706994 View Abstract
- Trynka G, Hunt KA, Bockett NA, et al. Dense genotyping identifies and localizes multiple common and rare variant association signals in coeliac disease. Nat Genet. 2011 Nov 6;43(12):1193-20. PMID 3242065 View Abstract