What is the Galleri blood test and what does it do?

The Galleri blood test is a new development designed to detect signals from 50 different types of cancer, aiming to improve early cancer screening.

How accurate is the Galleri blood test?

The test has a reported positive predictive value of 62% and a specificity of 99.6%, but its sensitivity in detecting true cancer cases is around 40.4%.

Will the Galleri blood test reduce cancer deaths?

There is currently no evidence that widely using the Galleri test reduces cancer deaths, though it shows promise for earlier detection.

Home / Health / New Blood Test Detects 50 Cancers Early

New Blood Test Detects 50 Cancers Early

27 Nov, 2025

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Summary

New blood test may boost early cancer detection effectiveness.
Galleri test identifies signals from 50 different cancer types.
Test shows 62% positive predictive value, missing many cancers.

A novel blood test, known as Galleri, has emerged as a beacon of hope in the ongoing battle against cancer, offering the potential for earlier detection. Developed by US firm Grail, this test is designed to identify signals from 50 different types of cancer, aiming to significantly improve the effectiveness of routine screening. Early trial results have been described as "exciting" by researchers, suggesting a significant step forward in oncology.

The Pathfinder 2 trial, which involved over 23,000 participants, reported that the Galleri test could detect cancer in 62% of positive cases. It also demonstrated high specificity, correctly ruling out cancer in 99.6% of disease-free individuals. Despite these promising figures, a sensitivity rate of 40.4% means the test missed a substantial number of cancers. This shortfall raises concerns about potential false reassurance from negative results.

While the Galleri test may become a valuable tool in future screening programs, experts caution that its current limitations, including low sensitivity and high cost ($949 in the US), mean it is not a standalone solution. Further evidence is needed to demonstrate its impact on reducing cancer mortality rates. The early data is encouraging, but tempered optimism is advised.