What blood tests can — and can’t — reveal about your health

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What can a blood test tell you about your health?
WATCH: Routine blood tests can reveal potential health risks – Mar 3, 2019

We’ve all had routine blood tests — the majority of people get one during an annual physical.

How often someone needs blood drawn really depends on their condition, said Dr. Doug Tkachuk, scientific director of hematology and laboratory medical director at Dynacare based in Brampton, Ont. There are also hundreds of types of blood tests that patients can take.

“Blood tests are usually ordered at a caregiver’s discretion, who is able to determine if the tests are necessary,” he told Global News. “I would advise patients to discuss if they should be having any blood work done for themselves if they have recently switched doctors or have not had a check-up for several years.”

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Some need more tests than others. Patients with a recent diagnosis of Type 2 diabetes may need to have their blood taken every three to four months to monitor their Hemoglobin A1C or blood glucose levels, he added.

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Chris Carson, senior vice-president, partner relations of laboratory services provider LifeLabs added a blood test can also help patients understand their overall health. “Results from blood testing can help confirm the cause of health concerns or rule out any potential concerns.”

Blood tests have also evolved, and some tests may even be able to detect cancer down the road. Carson noted there is more work around genetic testing that continues to be researched.

“The lab-testing industry is advancing at a rapid pace and new tests are being developed and brought to market every day. ”

What a blood test can tell you

Blood tests show us whether the levels of different substances in our blood fall within a normal range, Tkachuk said. “Ranges will vary depending on age, gender and race – but in most cases, ‘normal’ is defined as levels seen in 95 per cent of healthy people in a specific group.”

Overall, a test will indicate specific markers including red and white blood cell counts, blood sugar, hemoglobin, cholesterol and vitamin levels. A test can also reveal the presence of specific diseases.

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“Blood tests also can help find potential problems early, when treatments or lifestyle changes may work best. Blood tests can also assess individuals’ risk of acquiring diseases, for example, risk of getting diabetes or heart disease.”

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Carson added 70 per cent of health-care decisions are based on diagnostic results. “[This] makes blood work a critical component in establishing a baseline for health while also helping to confirm the cause of health concerns or rule out any potential concerns.”

What a blood test can’t tell you

But they can’t uncover everything. While blood tests can indicate normal or abnormal levels for many conditions, they may not always be able to show health-care professionals the cause of specific symptoms, Tkachuk said.

“For example, a patient with arthritis might show elevated levels of inflammation in their blood work, but other tests won’t be able to explain pain or discomfort they might be experiencing,” he explained.

“With that information in mind, health-care professionals can begin to look for other potential causes to treat arthritis symptoms – in this case, factors such as diet and exercise, sleep patterns and overall stress levels.”

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Researchers say new blood test can detect cancer years before

If you want specifics from your blood test like hormones levels or if you have any STIs, you need to communicate this with your doctor.

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“While [the doctor] may not suggest looking for markers such as the presence of STIs or hormone levels, if this is of concern to a patient, then I would encourage them to have the conversation and request getting this blood work done,” he continued.

Going through the procedure

Some people just don’t like needles and Tkachuk added a common myth about blood tests is that they are painful or stressful. “A phlebotomist, the person who collects the blood sample, is a trained medical professional who will help put the patient at ease and make the experience as pleasant as possible,” he said.

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For those who have a fear of extracting blood, some phlebotomists have tricks to distract the patient and some companies have even created new devices that focus less on the syringe.

Tkachuk said after your blood test is complete, you may not hear back from your health-care professional — especially if the results are not abnormal.

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“Getting a full understanding of your blood test results can help you make good decisions about your diet and lifestyle and continue to maintain healthy habits. If things appear to be normal following a blood test, it’s still a good idea for patients to be proactive and follow up with their doctor, so that they can get an overall picture of their health and wellness.”

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