The secrets in your blood

It’s considered sacred by many religions, but science treats it with no less awe. Blood can tell us a lot about our health, from warning us about disease to unlocking our DNA.

A vial of blood will soon do more in the fight against common diseases that become riskier as we age. The latest research and clinical trials aim to make tests more accurate, less expensive and more efficient at spotting and monitoring disease. Not only that, but they’ll also help us avoid expensive, invasive and costly diagnostics with long wait times.

Here’s a look at some of the latest advances when it comes to your blood.

One test, many types of cancer

Unfortunately, tumours don’t always keep their cells to themselves. Some cells, known as circulating tumour cells or CTCs, break free and travel through the body looking for a new home. They’re behind the deadly spread of cancer — but they can be hard to spot. You might see a few among millions of white blood cells and billions of red. Previous tests could count them, but not collect them for analysis.

Now the technology is becoming more refined. Researchers at Massachusetts General Hospital have been developing a test to trap these special cells, a test known as CellSearch. Special microchips covered in tiny “microposts” that are coated with cancer-binding antibodies filter out CTC cells from a patient’s plasma — allowing the cells to be collected and analyzed. A recently announced five-year, $30 million dollar partnership between Johnson & Johnson and Massachusetts General Hospital aims to make this test cheaper and easier to use.

What will this mean for patients? This “liquid biopsy” is still in its infancy, and some experts say it will take 3-5 years to develop and test it. The immediate goal is to help doctors assess how aggressive a patient’s cancer is and if treatments are successful — without having to rely on CT scans and biopsies. Experts will also be able to spot mutations and adjust treatment options accordingly.

Experts also hope the test will someday be used to routinely screen for common cancers. Whether it will be used instead of conventional screening methods (like mammograms or colonoscopies) or alongside them is still up for debate. (Read the full story on CBC News.)

Early indicator of Alzheimer’s

Can a disease that affects the brain show up in your blood? Yes, according to a study out of the Scripps Research Institute in Florida that shows promise for detecting Alzheimer’s disease and other forms of dementia in the blood. The principle behind the test is that the body’s immune system responds to invaders by creating antibodies. Identify and test for the antibodies and you’ll find evidence of the disease.

While the trial was small and a lot more investigation is needed, researchers were able to pinpoint two antibodies in the blood of Alzheimer’s patients using artificial molecules called peptoids. Don’t get too excited yet: the test is nowhere near being ready for use. However, it signals a new direction for diagnosing Alzheimer’s disease — as well as a host of other conditions including pancreatic and lung cancers — in their earliest stages.

Other tests are in the works as well, like a skin biopsy test and a combination of lumbar puncture test and brain scan. Even though there is currently no effective treatment or cure, scientists hope better tests can help find people in the early stages of Alzheimer’s who would be candidates for clinical trials of treatments and vaccines. (For more information, see BBC News.)

Help diagnose a heart attack

Hailed as one of the top medical breakthroughs of 2010 by Time Magazine, blood tests can now help doctors tell if you’re suffering a heart attack. Remember, not everyone experiences obvious symptoms like acute chest pain. Vague symptoms like chest discomfort and nausea can be misleading.

Along with your medical history, a physical examination and an electrocardiogram, a test known as creatine kinase or (CK) can detect damage to the heart muscle. Changes in the level of a CK enzyme can also signal trouble because it continues to increase during a heart attack.

Other tests look at level of cardiac muscle proteins known as troponins, which help control the contraction of the heart muscle. These tests are so sensitive they can even detect minor damage that doesn’t show up on CK tests. The American Hearth Association notes that these tests could be useful in identifying patients who are at a higher risk for serious problems. (Visit the American Heart Association website for more information.)

Detecting Down’s Syndrome and other abnormalities

Some patients may benefit from blood work very early in life — in the womb, in fact. According to a study in the British Medical Journal, a blood test that examines the genes of both mother and baby can help rule out birth defects and Down’s Syndrome in high-risk pregnancies (like in older mothers).

Do we need another way to spot these issues? Yes, say experts, because current tests — namely amniocentesis and chronic villus sampling (CVS) — are invasive and can lead to a miscarriage. Since there were no false-negatives found with this test, the study’s authors believe the test could eventually eliminate most of the need for these risky procedures. However, many experts have adopted a more moderate stance and note it will be a welcome addition to the technologies that are currently available — but it won’t displace them just yet.

How soon will at-risk moms be able to try it? Unfortunately, widespread use is still a few years away because the test is expensive and time consuming. Researchers need to make it more efficient and less costly first. (For more information, see the story on WebMD.)


A more palpable diabetes test

While not as ground-breaking as other advancements, the World Health Organization (WHO) recently accepted a new test to diagnose diabetes. The test has been around for a while and has been mainly used to monitor glycaemia in patients who already have the disease. However, improvements to the test — like standardized measures and lower costs — have made it a more practical tool for diagnosis.

What makes glycated haemoglobin, or HbA1c, different from the tests we have now? Simplicity and convenience. Patients don’t have to fast for hours beforehand, nor down a glucose drink and wait around. HbA1c can also provide doctors with information about blood glucose levels in the proceeding two to three months — not just the time the test is taken.

Naturally, there’s a catch — this test isn’t as cheap as the others, so it could take some time for developing countries to adopt it. With the incidence of type 2 diabetes set to increase rapidly in the coming decades, researchers will continue to look for better ways to diagnose this disease — and as early as possible.

For more information, see the WHO website.

Naturally, this is just a quick overview of some of the breakthroughs in the works. It’s important to remember that many of these tests are still under development and it’s going to take a while before we see their widespread use. However, the approaches and methods often have widespread implications for other conditions. There will be a lot of exciting changes to come — but it will take more than a little patience on our part.

Sources: American Heart Association, BBC Health, CBC News, The Globe and Mail, MedicineNet, The New York Times, WebMD, World Health Organization

Photo © Pali Rao

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