ABSTRACT
Celiac disease [CD] is an auto-immune disorder. The prevalence of CD has been estimated mainly based on serological tests. The aim of this study was to evaluate the seroprevalence of celiac disease in the adult general population of Mashhad, northeast of Iran and pitfall of serology in epidemiological studies considering the importance of serology titer
Materials and Methods: 1558 subjects aged 35 to 65 years and 1025 individuals aged between 15 to 35 years were selected randomly from multistage cluster sampling papulation for this cross sectional study. Anti-tissue transglutaminase [tTG]-IgA assay was performed by ELISA[Enzyme-Linked Immunosorbent Assay]. The manufacture's cut-off point of anti tTG was 20 IU/mL and the prevalence of positive serology was estimated based on being just above the upper limit of normal [20 IU/mL], twice or three times above the normal value at 40 and 60 IU/mL, respectively
Results: In both age group 35-65 year-old and 15 to 35 years adults, the prevalence of positive serology was 1.2% for anti-tTG level more than 60 IU/mL, which was three times of the kit references [95% CI: 0.7- 1.9] and [95% CI: 0.7-2.1], and based on our previous study in Mashhad if we consider the cut-off point as 76 IU/mL anti-tTG for mucosal atrophy, the prevalence of CD would be 0.69
Conclusion: Epidemiological data of CD is mainly based on serology and as these tests are to some extent non-specific at lower levels, the accuracy of the previous reported prevalence of CD in some studies are questionable and level of anti-tTG is important
ABSTRACT
Background: Duodenal biopsy is required for diagnosis of celiac disease in adults, although some studies have suggested adequate accuracy of serology alone
Objective: We aimed to assess the correlation between anti-tissue transglu-taminase [tTG] titer and pathological findings and to define the specific level of tTG for predicting celiac disease in adults without the need for biopsy sampling
Methods: This descriptive study was done on 299 participants
The tTG titer and pathological findings of duodenal biopsy samples were used for this study Analysis of Receiver operating characteristic [ROC] curve was used to find a cut-off point of anti-tTG antibody for mucosal atrophy
Results: Mean tTG titers was significantly higher in patients graded as Marsh III>/= 3 [p=0.023]. ROC curve analysis showed 89.1% sensitivity for cut-off point>/=76.5 lU/mL of anti-tTG. For Marsh>/= II, specificity was 28% and positive predictive value was 91%
Conclusion: There is a linear correlation between increasing tTG level and Marsh I to III. Specificity of tTG titer more than 200 was 100% for Marsh >2.