Australians have seen a flurry of headlines announcing the arrival of blood tests for Alzheimer’s disease.

The news follows the Therapeutic Goods Administration’s approval of new blood tests for clinical use and the launch of the Asia-Pacific Centre of Excellence for Alzheimer’s Disease Diagnosis at Neuroscience Research Australia (NeuRA) in Sydney.

These developments promise earlier, simpler and more accessible testing for Alzheimer’s, the most common form of dementia.

But what are these blood tests? What do they actually tell you? Should everyone over 60 ask their GP for one? And what happens if the result is positive?

Until recently, confirming Alzheimer’s usually required either specialised brain imaging (known as amyloid PET scans) or a lumbar puncture to examine proteins in the cerebrospinal fluid surrounding the brain and spinal cord.

Both approaches work well but have limitations. PET scans are not widely available and are expensive (although the Medical Benefits Schedule provides a subsidy). Lumbar punctures are invasive and patients are concerned they’ll be uncomfortable.

So researchers have spent the past decade or so asking whether the same biological changes seen in the brain could also be measured in blood.

The answer now appears to be yes.

Advances in laboratory technology mean tiny amounts of protein released from the brain can now be measured accurately in a standard blood sample.

This allows clinicians to estimate whether the biological changes associated with Alzheimer’s are likely to be present without immediately needing more invasive or expensive investigations.

There’s more than one Alzheimer’s blood test

There........

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