Single Blood Test Reveals Biological Ages of Different Organs and Bodily Systems

Aging does not occur uniformly across the body. While some organs may age rapidly, others remain healthier for longer due to lifestyle, environmental, and genetic factors. Traditional biological age tests, such as epigenetic clocks, provide only a single number and fail to show which body systems are most at risk. Scientists have now created a more advanced test capable of assessing aging across multiple physiological systems with greater precision.

Researchers from Yale University (New Haven, CT, USA) described this new approach, called the Systems Age test, in the journal Nature Aging. Developed using data from over 7,500 people, the test combines blood-based biomarkers such as cholesterol and blood sugar with DNA methylation patterns to provide system-specific biological age scores. By training machine learning models, the team designed a single blood test that can measure aging in 11 systems, including the heart, lungs, brain, metabolism, and immune system.

Image: Hierarchy of heterogeneity in aging (Photo courtesy of Nature Aging, 2025, DOI: 10.1038/s43587-025-00958-3)

To validate their method, scientists tested the model on blood samples from more than 8,000 individuals. The results showed it predicted age-related diseases more effectively than older epigenetic clocks. For example, the heart score from the new test was a stronger predictor of heart disease compared to standard biological age measures, demonstrating the tool’s superior diagnostic accuracy.

The findings also revealed significant variability in aging patterns across individuals. People with the same overall biological age often showed different rates of aging across organs. This insight could help doctors identify which systems are most vulnerable and deliver more personalized strategies for prevention and treatment, ranging from lifestyle changes to targeted therapies.

“By providing system-specific scores, Systems Age may better pinpoint which age-related conditions individuals are at risk for,” wrote study author Morgan Levine.

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