Biomarker could make dementia blood tests 100% accurate

A biomarker that has been identified in the blood could be key to diagnosing dementia early through a simple blood test, scientists have found. Researchers at King’s College London discovered neurofilament light chain (NfL) in people with mild cognitive issues helped them pick up on dementia.

Identifying dementia early is vital to help slow its progression, but there’s no single diagnostic test. Instead, a combination of memory analysis, mental-agility evaluations and brain scans are used to piece it together and this is only possible after concerns have been raised over an individual’s memory.

Scientists have been exploring the idea of using a blood test to detect brain disorders for a while. A number of studies have suggested biomarkers can be found in the blood for various diseases before any symptoms present.

In the King’s College London study, they analysed the blood samples of 3,000 patients, identifying dementia in those with mild cognitive problems with up to 100 per cent accuracy. Being able to detect the condition when clinical symptoms are not definitive could help to prevent cases where dementia is mistaken for depression in the early stages.

Dr Abdul Hye, senior research scientist and study author, said: "For the first time we have shown across a number of disorders that a single biomarker can indicate the presence of underlying neurodegeneration with excellent accuracy.

"Though it is not specific for any one disorder, it could help in services such as memory clinics as a rapid screening tool to identify whether memory, thinking or psychiatric problems are a result of neurodegeneration."

In the past, scientists have been able to detect biomarkers in the cerebrospinal fluid around the brain and spine. Collecting this substance requires an invasive procedure, whereas analysing the blood is much more straightforward.

Neurodegenerative diseases damage nerve fibres, releasing NfL into the blood. The key is being able to detect the protein at low levels to facilitate early diagnosis and even shorten clinical trials for potential treatments.

Of the 3,000 participants in the study, those who had been diagnosed with a neurodegenerative disease were found to have higher levels of NfL in their blood than the healthy controls.