With a blood test that measures the Alzheimer's marker p-tau217, the disease can be detected up to 20 years before it causes symptoms. The test is described as groundbreaking and has been used for some time in specialist healthcare in Sweden - but then in combination with other tests. Health centres are recommended to refuse testing to people who are "just" worried about being affected. This has opened the door to private providers, and healthy people can already test themselves at private clinics, including in Stockholm.
This is completely the wrong way to use the method, says Henrik Zetterberg, professor of neurochemistry at the University of Gothenburg, who has led the development of the test method in Sweden.
He explains that there are many different methods for measuring p-tau217 and far from all of them are reliable. This can lead to false positive or negative results.
Must be investigated
And just because you test positive doesn't mean you'll get Alzheimer's. You could die from other diseases. The results need to be investigated further.
The criterion for getting a blood test for p-tau217 in healthcare is that you have symptoms that raise suspicion of Alzheimer's.
But the first step is to start with a basic memory assessment and rule out other diseases that can also affect memory. Only after that can you proceed with blood tests, says Henrik Zetterberg.
Madelene Johanzon is a specialist doctor with expertise in cognitive disorders. She is also one of those currently reviewing the national care programme for which tests should be used and who should be allowed to take them.
No approved medication
We are getting more and more questions about the new blood tests and there will be even more when we have approved drugs to use. But for now, I don't think they should be used because you don't know what to do if you test positive, she says.
There is currently no approved medication to use.
"It can cause that. I have seen people stop working early and relatives have become worried and questioned whether the person should continue driving. It can be tragic for everyone involved," says Madelene Johanzon.
She sees both advantages and disadvantages of testing for the disease.
Knowledge is usually good, but if you find out that you are at risk of getting sick - what should you do? We don't know that today.
Facts: The new Alzheimer's test
P-tau217 is a protein that is normally found inside nerve cells. Its concentration is elevated in Alzheimer's by about 2-5 times the normal level. It is therefore used as a marker for the disease, either in spinal fluid or in blood.
Measurement of p-tau217 is likely to be of great importance for screening people at risk.
To be able to take the test in healthcare, it is usually required that you already have symptoms of the disease.
Private healthcare companies offer tests for healthy people without symptoms for around SEK 5,000.
There is still no approved treatment for Alzheimer's in Sweden, but studies are underway.
