Six important blood tests you should know about

Be proactive with your health care using this expert advice on the bloodwork to ask for and how to read the results
blood tests, bloodwork, medicine, health

Many of us attend our annual physical in a passive manner; we get our measurements, bloodwork and current health indicators, then hoping for the best. I truly believe we must take an active role in our own health care. One of the most powerful steps you can make to take charge of your wellness is to have regular blood tests and request a copy the results. Most importantly, know your optimal range and make it a habit to consult a preventative health expert, like an naturopathic doctor, at least once a year (although I prefer once a season).

Your bloodwork is a very important piece of your health puzzle.  This week I thought I would share some tips of a few health tests that can affect your energy, cravings and metabolism, which can be completed by your doctor.

Thyroid hormone: Without enough thyroid hormone, every system in the body slows down. Those who suffer from hypothyroidism often feel tired, tend to sleep a lot, experience constipation and stubborn weight gain. Extremely dry skin, hair loss, brittle hair, splitting nails, slower mental processes, feeling cold, infertility, poor memory, depression, decreased libido or an inability to lose weight are also symptoms to watch for.

Thyroid disease is most accurately diagnosed by blood tests that analyze thyroid gland function, including your thyroid-stimulating hormone (TSH). Elevated levels of TSH suggest that the thyroid gland is not responding properly to the signal from the pituitary gland instructing it to make more hormones. For optimal well-being, I prefer to see the TSH between 0.35 to 2.0, although many lab ranges are as high as 5.0, which can leave the patient untreated despite “normal” blood tests. In addition, you should ask for Free T3 and Free T4, with a goal to have them in the middle of your lab’s reference range. If you have a family history of thyroid disease it is wise to test for thyroid antibodies. The presence of antibodies predicts a slightly higher rate of propensity towards hypothyroidism, and should be monitored on a yearly basis.

Insulin and glucose: Glucose and insulin are implicated in many age-related diseases, such as type 2 diabetes, hypoglycemia, carbohydrate metabolism, hypertension, heart disease, insulin resistance and stroke. These tests require a fasting blood level; therefore, a 10- to 12-hour fast is required before the collection of a blood sample. Optimal results for glucose is less than 5.2 mmol/L (Canada) or 86 mg/dL (US units). A value of less than 36 pmol/L (Canada) or 5 mU/mL (US units) is ideal for fasting insulin. Insulin resistance can be associated with a glucose reading greater than 6 mmol/L (or 100 mg/dL) and fasting insulin greater than 36 pmol/L (or 5 mU/mL).

Insulin resistance is a metabolic disorder which can develop as a result of poor dietary habits (excessive intake of sugar, unhealthy fats and carbohydrates, or insufficient protein), stress, obesity, or lack of exercise. Diagnosis is associated with increased risk of type 2 diabetes, obesity, high blood pressure, stroke and coronary heart disease. Remember this: Insulin is the first thing to go wrong in insulin resistance, while blood sugar is the last. Testing insulin, therefore, will allow you to be much more proactive in the prevention of diabetes and heart disease.


Ferritin (Iron): Ferritin is considered an iron-storage protein that keeps the iron in a dissolvable and usable state, which also makes the iron non-toxic to cells around it. A blood test for ferritin measures the iron that is readily available for use. Optimal levels in women should be close to 70 and 100 for men. Low levels of iron are also problematic and are associated with fatigue, decreased athletic performance, ADD/ADHD and hair loss. A recent study published in the European Journal of Clinical Nutrition found an association between depression and decreased ferritin levels before the occurrence of anemia. Women with heavy menstrual bleeding are more susceptible to low iron levels, which makes it one of the top must-have blood tests. If your iron levels are too low, it will also impact the effectiveness of your thyroid treatment if you are on medication. Abnormally high levels of ferritin can increase the risk of heart disease in both men and women because of the tendency to increase inflammation. If your ferritin is too high (more common with men or post-menopausal women), you should speak to your doctor about the possibility of donating blood; if too low, use a supplement of iron citrate with 1,000 mg of vitamin C.

Progesterone: Progesterone, naturally highest in the luteal phase of the menstrual cycle, works wonderfully to prevent many PMS symptoms such as anxiety, headaches, sleep disruption, water retention and breast tenderness. Progesterone helps protect against anxiety, uterine fibroids, and fibrocystic breast disease. It enhances metabolism and is crucial for fertility. Unfortunately progesterone deficiency becomes very common for many women in their 30’s and 40’s, primarily because stress causes progesterone depletion. In my practice I often see patients with low progesterone who have higher cortisol levels or impaired adrenals. To get an optimal reading of your progesterone levels you should conduct your blood test on day 19 to 21 of your menstrual cycle (with day one being the first day of bleeding). An optimal value is close to 30.

25 hydroxy vitamin D3: Vitamin D has proven immune-enhancing, cancer protective, bone-building and insulin-regulating benefits. It is also important during pregnancy. Your levels should be over 125. If your vitamin D is low, add 2,000 to 5000 IU of vitamin D3 each day to your regimen, in addition to your multivitamin and calcium/magnesium supplement.

Highly sensitive C-reactive protein (Hs-CRP): Hs-CRP is a marker of inflammation and a risk factor for arterial disease. Levels tend to increase as body fat increases and with insulin resistance. An optimal value is less than 0.8, although the Life Extension Foundation recommends less than 0.55 mg/L for men and less than 1.5 mg/L for women. This test is also important for breast cancer survivors and should be tested along with fasting and two-hour PC insulin levels. High CRP or insulin is associated with increased risk of recurrence.

Natasha Turner, N.D. is a Toronto-based naturopathic doctor and founder of the Clear Medicine wellness boutique. She is also the author of the bestselling book The Hormone Diet


Subscribe to our newsletters for our very best stories, recipes, style and shopping tips, horoscopes and special offers.

By signing up, you agree to our terms of use and privacy policy. You may unsubscribe at any time.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.