Celiac.com 06/04/2010 - A team of researchers recently set out to assess the positive predictive value of blood test screening for possible cases of celiac disease.

The team included Peter Toftedal, Christian Nielsen, Jonas Trolle Madsen, Kjell Titlestad, Steffen Husby, and Søren Thue Lillevang. They are affiliated with the Hans Christian Andersen Children's Hospital, and the Department of Clinical Immunology of Odense University Hospital in Denmark. P. Toftedal and Ch. Nielsen made contributions to the final published article.

In deciding which possible celiac disease cases might require duodenal biopsy, doctors rely mainly on tests for celiac disease antibodies, such as immunoglobulin A (IgA) anti-tissue transglutaminase (anti-tTG), IgA endomysium antibody (EMA), IgA and IgG anti-gliadin antibodies (IgA and IgG AGA).

For their study, the research team wanted to assess the diagnostic quality of blood testing for possible cases of celiac disease. They did this by performing celiac disease blood tests (IgA and IgG AGA, anti-tTG and EMA) on 11,915 subjects.

They then combined the serological data with clinical data and duodenal biopsy results using a unique Danish personal identification number.

They found that positive predictive value (PPV) fluctuated in accordance with various combinations of positive celiac disease antibodies. They found the highest predictive value (97.6%) when results for IgA and IgG AGA, anti-tTG and EMA antibodies were all positive.

The team used a logistic regression model at initial blood screening to predict the probability of later biopsy-proven celiac disease in relation to concentrations of IgA AGA and anti-tTG.

They found that anti-tTG concentrations correlated strongly with EMA positivity, number of additional positive antibodies, and higher PPV.

The anti-tTG concentration upon first blood screening for celiac disease was highly informative in relation to EMA positivity, number of additional CD specific antibodies and PPV.

Lastly, results for the high-risk patient group showed that
anti-tTG and IgA AGA concentrations at initial serological screening accurately predicted probability of future biopsy-proven celiac disease.

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