Researchers are exploring blood biomarkers as a way to predict Alzheimer’s disease.

A study involving Skåne University Hospital in Sweden and UNC School of Medicine in the USA found that a new blood test predicted Alzheimer’s with 91 per cent accuracy in both primary and specialty care. 

This compares to 61 per cent accuracy in primary care and 73 per cent in specialty care using traditional clinical evaluations.

An additional study suggested that changes in blood biomarkers from midlife could indicate late-life dementia risk. 

Despite these promising results, the blood test is not yet accurate enough to be used alone and requires further research.

In an editorial, Dr Stephen Salloway, Dr Christopher Rowe, and Dr Jeffrey Burns noted the transformative potential of early diagnosis in Alzheimer’s management, saying; “Alzheimer’s disease is increasingly viewed as a treatable condition and managed like other major chronic diseases”.

The focus on early diagnosis stems from advances in detecting Alzheimer’s markers - amyloid and tau proteins - through cerebrospinal fluid tests and PET scans. 

However, these methods are expensive and less accessible, prompting interest in plasma biomarkers. 

New technologies, such as mass spectrometry and ultrasensitive immunoassays, have enabled accurate measurement of low protein levels in blood samples.

The APS2 blood test, measuring plasma phosphorylated tau 217 (p-tau217) and amyloid-β ratios, showed 91 per cent accuracy in predicting Alzheimer’s pathology, outperforming traditional clinical evaluations. 

This test could improve diagnostic accuracy, especially in primary care where diagnosing Alzheimer’s is challenging. 

Early diagnosis is vital with the recent approval of monoclonal antibody treatments targeting amyloid plaques in early-stage patients.

While the APS2 test is promising, it is not ready for widespread use as a standalone diagnostic tool. 

The experts say it is most effective for those with mild cognitive impairment or dementia, with lower predictive value for those with subjective cognitive decline.