Can you get a blood test for dementia?

A recent study highlighted by the Alzheimer's Society revealed a startling fact: 56% of people wait a year or more before seeking a dementia diagnosis after first noticing dementia symptoms. Dementia is the most feared health condition in the UK, perhaps explaining also why almost two-thirds of people surveyed (62%) felt a diagnosis would mean their life was over, according to the organisation.

As a result, the search for a simple blood test for dementia, one of the most urgent pursuits in modern medicine. But can a blood test show dementia with the certainty we need?

Many people wonder if a straightforward blood test can confirm dementia, similar to tests for other conditions. Currently, there is no single, definitive test that can diagnose dementia on its own. However, scientific breakthroughs are already happening. Researchers are making incredible strides with blood tests for dementia, identifying biomarkers linked to specific types of the condition.

Let's explore the current diagnostic tools and the groundbreaking research that promises a future where an early and accurate diagnosis is more accessible than ever. This journey is crucial, as dementia is arguably the greatest health challenge our society is facing today.

The Quest for a Breakthrough: The Rise of Blood Testing

The idea of a simple blood test to identify dementia has long been a goal for the medical community. This is because the current method of diagnosing dementia is long and difficult, and includes uncomfortable, invasive tests. For decades, confirming the presence of proteins associated with Alzheimer's disease required either examining cerebrospinal fluid or using advanced brain scans.

The blood biomarker challenge has spurred Alzheimer's Research UK and other global institutions to accelerate the development of simpler diagnostic tools. The goal is to develop cutting-edge blood tests that can be used in routine clinical settings. Researchers are investigating different blood tests that can measure key proteins, such as amyloid and tau, directly from a blood sample.

Significant medical research from institutions like the National Institute for Health and Care Research is focused on validating these tests. The aim is to bring blood tests to the forefront of the diagnostic process, making early detection a reality for the wider dementia community. This progress is vital for ensuring a timely and accurate diagnosis for everyone.

Types of Biomarkers and Tests

Biomarkers are measurable indicators of what’s happening in the body. These can be found in the blood, other body fluids, organs, and tissues. For dementia, several types of biomarkers help in detection and diagnosis.

While new blood tests are on the horizon, diagnosing dementia today involves a comprehensive approach. Doctors use a combination of methods to build a complete picture of a person's brain health. These established tests for diagnosing the condition remain the gold standard.

Brain Imaging

Brain scans allow doctors to see the physical changes in the brain. They are essential for identifying the potential source of disease symptoms, such as tumours, evidence of strokes, or shrinkage in specific brain regions.

Computerised Tomography (CT) Scans

A CT scan uses X-rays to create detailed cross-sectional images of the brain. It can reveal atrophy (shrinkage) of brain areas, a common sign in many dementias. It is also effective at ruling out other causes for cognitive decline, such as blood clots or infections.

Magnetic Resonance Imaging (MRI)

An MRI uses powerful magnetic fields to produce highly detailed images of the brain's structure and tissues. It is particularly useful for detecting brain atrophy and examining the health of blood vessels, which is critical for identifying vascular dementia.

Positron Emission Tomography (PET) Scans

A PET scan, or positron emission tomography, is a more advanced imaging technique. It uses a radioactive tracer to measure chemical activity and specific molecules in the brain. Different types of PET scans look for different signs:

• Amyloid PET Scans: These scans are specifically designed to measure the build-up of a protein called amyloid. Irregular deposits of this protein form the amyloid plaques that are a classic indicator of Alzheimer's disease. However, some people may have these plaques without ever developing Alzheimer's.
• Tau PET Scans: These scans detect the abnormal accumulation of tau protein inside brain cells. These tau tangles are another key feature of Alzheimer's and other neurodegenerative diseases.
• FDG PET Scans: This type of scan measures how the brain uses glucose for energy. Reduced metabolic activity in certain brain areas can be a strong indicator of conditions like frontotemporal dementia.

Cerebrospinal Fluid (CSF) Biomarkers

The cerebrospinal fluid is a clear liquid that surrounds the brain and spinal cord, acting as a protective cushion. By taking a sample of this fluid via a lumbar puncture (spinal tap), specialists can measure the levels of key proteins.

Low levels of beta-amyloid 42 in the CSF can suggest the protein is building up in the brain, while high levels of tau and phospho-tau indicate damage to brain cells. These markers are highly valuable for the diagnosis of Alzheimer's disease.

• Beta-Amyloid 42: A specific form of beta-amyloid, a protein fragment that accumulates to form plaques in the brain, linked to Alzheimer's disease. Low levels in CSF suggest that beta-amyloid is being deposited in the brain, which is a sign of Alzheimer’s.
• Tau and Phospho-Tau: Tau is a protein that helps maintain the structure of brain cells. Phospho-tau is a modified form of tau that forms tangles inside brain cells in Alzheimer's and other dementias. High levels of tau and phospho-tau in CSF indicate the presence of these tangles, which are harmful to brain function and are correlated with Alzheimer's disease and other neurodegenerative conditions.

Blood Tests

Blood tests are becoming more accurate in identifying dementia biomarkers. For instance, levels of beta-amyloid can now be measured, though these tests are primarily available only in research settings. Despite advancements, dementia blood tests alone cannot provide a definitive diagnosis.

• Beta-Amyloid: A protein that can form clumps or plaques in the brain, commonly found in Alzheimer's disease. These plaques disrupt communication between brain cells. Elevated levels in blood can suggest Alzheimer's disease.
• Other Proteins: Ongoing research is identifying additional proteins that may indicate different types of dementia.

Can Blood Tests Detect Dementia Reliably?

This is where the most exciting progress is being made. For years, the concentration of dementia-related proteins in the blood was considered too low to measure accurately. However, new ultra-sensitive technologies have changed everything.

Several blood tests for dementia screening are showing very promising results in research settings. They work by detecting specific forms of amyloid and tau proteins, the same biomarkers found in CSF and on PET scans. The research suggests that these new tests can help diagnose Alzheimer's disease, particularly in its early stages.

The Alzheimer's Association and Dementias Platform UK are supporting large-scale clinical trials to validate these tests. The goal is to see if a single test can provide an accurate diagnosis or if a combination of such tests is needed. Before they can be tested widely, research teams must ensure they are effective across the UK's diverse population. While the slow progress of the past has been frustrating, the current pace of discovery is remarkable.

How Dementia is Diagnosed in the UK

If you are concerned about your memory, the first step is to speak with your GP. An early consultation is key to getting the support you need.

Your GP Appointment

Your GP will want to understand your cognitive symptoms and overall health. They will ask about your medical history, any memory problems you've noticed, and how they affect your daily life. It is helpful to have a family member present to provide another perspective.

Your GP will conduct a physical exam, which may include checking your blood pressure, and will likely organise standard blood tests and a urine test to rule out other causes like infections or vitamin deficiencies. They may also use initial memory tests, such as the Montreal Cognitive Assessment, to gauge cognitive function.

Referral to a Specialist at a Memory Clinic

If other conditions are ruled out, your GP may refer you to a specialist. This could be a geriatrician, neurologist, or psychiatrist, often based in a dedicated memory clinic. The specialist's role is to conduct a more thorough investigation.

This process is focused on diagnosing dementia accurately. They will review your symptoms, conduct more detailed cognitive assessments, and may arrange for brain imaging like an MRI or CT scan. This comprehensive evaluation is essential for an early and accurate diagnosis.

Receiving a Formal Diagnosis

After gathering all the necessary information, the specialist will make a diagnosis. Receiving this news can be difficult, but it is a critical step. An accurate diagnosis of early Alzheimer's disease or another dementia allows you to understand what is happening and plan for the future.

It opens the door to potential new treatments that can help manage symptoms and gives you the ability to access vital care and support networks. The specialist will discuss the specific type of dementia, how it may progress, and the support services available.

Conclusion

So, is there a blood test for dementia that you can get today? Not as a simple, standalone diagnostic tool. However, the future is incredibly bright with various biomarkers and diagnostic tests that help in the detection and diagnosis of different types of dementia.

Research is rapidly advancing, and new blood tests are moving from the lab into clinical trials. For now, a combination of a physical exam, cognitive memory tests, and brain scans remains the most reliable path for diagnosing Alzheimer's and other dementias.

At Tiggo Care, we understand the complexities of dementia diagnosis and the challenges it poses to families. Our personalised dementia care service aims to maximise quality of life and provide comprehensive support for those living with dementia. Whether it's assisting with medication routines, meal preparation, or escorting to social events - our dedicated care assistants are here to help.

Contact Tiggo Care today to learn more about our tailored dementia care services and how we can support your loved one’s needs.