Blood Tests Show Promise for Early Detection of Crohn’s Disease

Recent research has focused on the potential for blood tests to detect Crohn’s disease in individuals before symptoms develop. Multiple studies have examined antibody levels and other blood markers to identify early immune responses linked to the disease.

One approach measures antibodies against flagellin, a protein found on gut bacteria, in blood samples from people who are currently healthy. Elevated levels of these antibodies have been observed in some individuals who later receive a Crohn’s disease diagnosis, with changes detectable up to two and a half years in advance.

The findings on flagellin antibodies were published in Clinical Gastroenterology and Hepatology. This research is part of the Genetic, Environmental and Microbial (GEM) Project, which began in 2008 and follows over 5,000 healthy first-degree relatives of Crohn’s patients worldwide.

In one study, researchers monitored 381 first-degree relatives of people with Crohn’s disease. Among these participants, 77 eventually developed the condition, and more than one-third of those had shown elevated flagellin antibody responses before their diagnosis.

What the numbers show

• 381 first-degree relatives were tracked in one study
• 77 participants developed Crohn’s disease during the study
• Over one-third of those 77 had elevated flagellin antibodies before diagnosis
• The average time from blood test to diagnosis was about 2.5 years

Other studies have explored different blood-based indicators for early Crohn’s detection. Research conducted by the Francis Crick Institute and Aalborg University found that routine blood test markers, including minerals and inflammation indicators, can show changes up to eight years before a diagnosis is made.

Machine-learning techniques have also been applied to routine blood test data. In Israel, a model analyzing such data detected predictive differences for Crohn’s disease more than ten years before diagnosis, with an area under the curve (AUC) of 0.61 at seven years pre-diagnosis.

Additional research using antibody profiling from the US Department of Defense Serum Repository identified distinct antibody signatures against viruses and bacteria that could predict Crohn’s disease up to ten years before diagnosis. This approach achieved an AUC of 0.90, suggesting a high level of predictive accuracy in that study.

Collectively, these studies indicate that blood-based markers, including specific antibodies and routine test components, are being investigated as tools for identifying Crohn’s disease risk before clinical symptoms appear. The ongoing GEM Project and related research continue to provide data on early immune changes in individuals at increased risk for the disease.

* This article is based on publicly available information at the time of writing.