A recent study by a team of researchers confirmed that most adults do not require a biopsy for a reliable celiac disease diagnosis.

BMJ Journals, gut.bmj.com ¹

Significance of this study

What is already known on this subject?

European Society for the Study of Paediatric Gastroenterology, Hepatology and Nutrition guidelines suggest that a diagnosis of coeliac disease (CD) can be made without taking duodenal biopsies.

The latest criteria suggest that a 10-fold increase in IgA antitissue transglutaminase (tTG) antibody levels in combination with EMA positivity is sufficient to make a diagnosis of CD in the absence of duodenal biopsies.

In adults, this approach has not yet been widely adopted into clinical practice, largely due to a lack of international multicentre data and testing in low CD prevalence cohorts.

What are the new findings?

Across three cohorts of adult patients, we have shown that almost all individuals with IgA tTG titres of ≥10×ULN have small intestinal mucosal changes diagnostic of CD (Marsh 3 lesions) on duodenal biopsy.

We show that IgA tTG titres of 10×ULN have 100% specificity at detecting Marsh 3 lesions in a cohort of 532 adults with a CD prevalence of 3.2%.

Finally, we found that an IgA tTG cut-off of 10×ULN performed well at identifying individuals with Marsh 3 lesions using different assays across multiple international sites. However, determining assay-specific thresholds and/or standardisation of tTG assays used with this pathway may help to optimise the accuracy and impact of this approach.

How might it impact on clinical practice in the foreseeable future?

This study supports a change in guidelines towards a no-biopsy approach for the diagnosis of CD within adult gastroenterology services.

The Study

Objective

We aimed to determine the predictive capacity and diagnostic yield of a 10-fold increase in serum IgA anti-tissue trans-glutaminase (tTG) antibody levels for detecting small intestinal injury diagnostic of coeliac disease (CD) in adult patients.

Design

The study comprised three adult cohorts.

Cohort 1: 740 patients assessed in the specialist CD clinic at a UK centre;
cohort 2: 532 patients with low suspicion for CD referred for upper GI endoscopy at a UK centre;
cohort 3: 145 patients with raised tTG titres from multiple international sites.

Marsh 3 histology was used as a reference standard against which we determined the performance characteristics of an IgA tTG titre of ≥10×ULN for a diagnosis of CD.

Results

Cohort 1: the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for IgA tTG levels of ≥10×ULN at identifying individuals with Marsh 3 lesions were 54.0%, 90.0%, 98.7% and 12.5%, respectively.
Cohort 2: the sensitivity, specificity, PPV and NPV for IgA tTG levels of ≥10×ULN at identifying individuals with Marsh 3 lesions were 50.0%, 100.0%, 100.0% and 98.3%, respectively.
Cohort 3: the sensitivity, specificity, PPV and NPV for IgA tTG levels of ≥10×ULN at identifying individuals with Marsh 3 lesions were 30.0%, 83.0%, 95.2% and 9.5%, respectively.

Conclusion

Our results show that IgA tTG titres of ≥10×ULN have a strong predictive value at identifying adults with intestinal changes diagnostic of CD. This study supports the use of a no-biopsy approach for the diagnosis of adult CD.

Read the entire article here.

Authors: Hugo A Penny1, Suneil A Raju, Michelle S Lau, Lauren JS Marks, Elisabeth MR Baggus1, Julio C Bai, Gabrio Bassotti, Hetty J Bontkes, Antonio Carroccio, Mihai Danciu, Mohammad H Derakhshan, Arzu Ensari, Azita Ganji, Peter H R Green, Matt W Johnson, Sauid Ishaq, Benjamin Lebwohl, Adam Levene, Roxana Maxim, Hamid Mohaghegh Shalmani, Mohammad Rostami-Nejad, David Rowlands, Irene A Spiridon, Amitabh Srivastava, Umberto Volta, Vincenzo Villanacci, Graeme Wild, Simon S Cross, Kamran Rostami, David S Sanders.

¹ https://gut.bmj.com/content/early/2020/11/02/gutjnl-2020-320913