Celiac disease laboratory tests
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: : Iqra Qamar M.D.[2]
Overview
Laboratory Findings
Electrolyte and Biomarker Studies
- Complete blood count (CBC)
- Liver function tests (LFTs)
- B12
- Vitamin D
- Folate
- Ferritin (+/- Ca, alk phos) – at diagnosis and annually
Serologic Markers
Serologic tests may be divided into 2 groups based upon antibodies against respective antigens:
- anti-TTG Ab tests
- anti-gliadin antibody tests
IgA endomysial antibody (IgA EMA):
- Endomysial antibodies bind to the endomysium and can be seen via indirect immunofluorescence producing a staining pattern. The target antigen is a tissue transglutaminase
- IgA EMA have high specificity and even low titres indicate a positive test result
- It has moderate sensitivity but high specificity for untreated celiac disease and is negative in treated patients.
IgA tissue transglutaminase antibody (IgA tTG):
IgG tissue transglutaminase antibody (IgG tTG)
IgA deamidated gliadin peptide (IgA DGP)
IgG deamidated gliadin peptide (IgG DGP)
NOTE:
- Serum IgA EMA and IgA tTG have the highest diagnostic accuracy
- The IgA and IgG antigliadin antibody (AGA) are not recommended for estabilishing diagnosis as they have low accuracy and give more false positive results when compared with IgA tTG and IgA DGP assays
- The anti-deamidated gliadin peptide (DGP) assays also have high diagnostic accuracy
Sensitivity and Specificity of Antibody testing:
Literature review has shown that IgA endomysial and IgA tissue transglutaminase antibodies have a sensitivity more than 95% and a specificity almost 100%. However variations in results are seen among different laboratories.[1][2][3][4][5][6]
| Test | sensitivity | specificity |
|---|---|---|
| IgA enomysial antibody | 85 to 98% | 97 to 100% |
| IgA tissue transglutaminase antibody | 90 to 98% | 95 to 97% |
| IgA deamidated gliadin peptide | 94% | 99% |
| IgG deamidated gliadin peptide | 92% | 100% |
| Test | sensitivity | specificity |
|---|---|---|
| HLA-DQ2 | 94% | 73% |
| HLA-DQ8 | 12% | 81% |
References
- ↑ Mäki M (1995). "The humoral immune system in coeliac disease". Baillieres Clin. Gastroenterol. 9 (2): 231–49. PMID 7549026.
- ↑ Abrams JA, Brar P, Diamond B, Rotterdam H, Green PH (2006). "Utility in clinical practice of immunoglobulin a anti-tissue transglutaminase antibody for the diagnosis of celiac disease". Clin. Gastroenterol. Hepatol. 4 (6): 726–30. doi:10.1016/j.cgh.2006.02.010. PMID 16630760.
- ↑ Swallow K, Wild G, Sargur R, Sanders DS, Aziz I, Hopper AD, Egner W (2013). "Quality not quantity for transglutaminase antibody 2: the performance of an endomysial and tissue transglutaminase test in screening coeliac disease remains stable over time". Clin. Exp. Immunol. 171 (1): 100–6. doi:10.1111/cei.12000. PMC 3530101. PMID 23199329.
- ↑ Sugai E, Vázquez H, Nachman F, Moreno ML, Mazure R, Smecuol E, Niveloni S, Cabanne A, Kogan Z, Gómez JC, Mauriño E, Bai JC (2006). "Accuracy of testing for antibodies to synthetic gliadin-related peptides in celiac disease". Clin. Gastroenterol. Hepatol. 4 (9): 1112–7. doi:10.1016/j.cgh.2006.05.004. PMID 16860613.
- ↑ Prince HE (2006). "Evaluation of the INOVA diagnostics enzyme-linked immunosorbent assay kits for measuring serum immunoglobulin G (IgG) and IgA to deamidated gliadin peptides". Clin. Vaccine Immunol. 13 (1): 150–1. doi:10.1128/CVI.13.1.150-151.2006. PMC 1356631. PMID 16426013.
- ↑ Kelly CP, Feighery CF, Gallagher RB, Gibney MJ, Weir DG (1991). "Mucosal and systemic IgA anti-gliadin antibody in celiac disease. Contrasting patterns of response in serum, saliva, and intestinal secretions". Dig. Dis. Sci. 36 (6): 743–51. PMID 2032515.