Why do clinicians limit lab testing?#

Why clinicians follow guideline-based, "Choosing Wisely" principles when ordering lab tests, what overtesting can cause, and how TeleTest balances patient access with evidence-based testing.

Lab tests feel like a quick, low-risk way to get answers. In practice, the right test at the right time is helpful and the wrong test (or the right test at the wrong time) can be harmful. This page explains the thinking behind guideline-based test ordering in Canada, what overtesting actually costs patients and the system, and how TeleTest navigates the line between access and evidence.

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Why clinicians act as gatekeepers#

In publicly funded healthcare systems like Canada's, clinicians are licensed to order tests that the province pays for. The system asks clinicians to apply judgment because:

  1. Resources are limited. Imaging machines, lab capacity, and clinician time are not infinite. Every test ordered without a good clinical reason is one less slot for a test that is genuinely needed.
  2. Costs are shared. Public lab and imaging services are paid for by taxes. A test ordered without a clinical reason ultimately raises costs for everyone or shifts wait times to people who need the resource more.
  3. Evidence-based practice is the standard. Clinicians are trained to order tests when the result will plausibly change what they do next - confirm a diagnosis, change a treatment, decide whether referral is needed. If a result won't change anything, the test usually isn't needed.
  4. Overtesting can harm patients. False-positive results lead to follow-up tests, anxiety, and sometimes invasive procedures (biopsies, surgery) for conditions the person never had.
  5. Some tests carry direct risks. Imaging with radiation, invasive procedures, and even routine blood draws (especially in older adults or people with veins that are hard to access) have small but real risks.
  6. Care should be coordinated. When the same test is repeated across multiple clinicians who don't share results, the system pays for it twice and the patient is left with conflicting interpretations.

This thinking is sometimes called "Choosing Wisely Canada" - a national initiative that publishes recommendations on tests and treatments that are overused.

What overtesting can cause#

Concrete examples of how unnecessary testing causes harm:

  • Imaging for low back pain. Most low back pain in adults gets better with time, movement, and physiotherapy. Routine MRI of the lower back finds "abnormalities" (mild disc bulges, mild arthritis) in many healthy people who have no pain. When those findings are reported, they often lead to extra appointments, injections, or even surgery for changes that were never the cause of the pain.
  • Screening for cancer in low-risk people. A screening test in a person who is not in the at-risk group is more likely to produce a false positive than a true positive. False positives trigger follow-up testing, biopsies, anxiety, and sometimes treatment for conditions the person never actually had.
  • Whole-body or "executive" health panels. These often include 60-80 tests, many of which produce a borderline-abnormal result by chance. The follow-up cascade can be costly, anxiety-inducing, and rarely changes how a healthy person should be managed.
  • Repeating tests too often. A test repeated more often than guidelines suggest rarely catches anything that the recommended interval would have missed, but it does increase the chance of a false positive and a downstream workup. For example, fasting glucose in a healthy non-pregnant adult without diabetes risk factors is recommended every three years, not every visit.

The first principle of medicine - "first, do no harm" - applies as much to tests as it does to medications.

Tests that are commonly over-ordered#

Tests where the evidence does not support routine use in most people:

  • Routine vitamin D in healthy, asymptomatic people. Vitamin D testing is recommended for specific conditions (suspected deficiency causing symptoms, malabsorption, chronic kidney disease, osteoporosis) but not as a routine "annual" measurement in well people.
  • T3 and reverse T3 thyroid testing. TSH is the test that guides almost all thyroid decisions. Reverse T3 is not a guideline-recommended test for thyroid management.
  • "Food sensitivity" panels (IgG-based). These are not validated for diagnosing food sensitivity. Mainstream allergy and gastroenterology guidelines do not recommend them.
  • Routine "tumour marker" panels in healthy adults. Tumour markers like CA-125, CA 19-9, and CEA are useful for monitoring cancers that have been diagnosed; they are not recommended as screening in people without symptoms or risk factors.
  • Routine cortisol blood draws to "check for adrenal fatigue". Adrenal fatigue is not a medically recognized diagnosis. Random cortisol levels in well people produce false positives and lead to unnecessary investigation.
  • Heavy-metal panels without an exposure. Without a specific exposure history, screening adults for heavy metals is not guideline-supported.

This doesn't mean these tests are never useful - they are useful for specific clinical questions in the right person at the right time. Routine, asymptomatic use is what isn't supported.

Tests that are commonly under-ordered#

There are also tests that are genuinely useful but often skipped by busy clinicians:

  • Ferritin in people with fatigue, restless legs, hair shedding, or heavy periods.
  • Vitamin B12 in older adults, vegetarians and vegans, people on long-term acid-suppressing medications, and people with neurological symptoms.
  • Vitamin D in people with osteoporosis, malabsorption (celiac disease, Crohn's), chronic kidney disease, or symptoms of deficiency.
  • Lipoprotein(a) - a once-in-a-lifetime test that strengthens cardiovascular risk assessment when there is a family history of early heart disease.
  • Apolipoprotein B - a more accurate measure of cholesterol-related cardiovascular risk than the standard LDL alone, particularly in people with diabetes, prediabetes, or metabolic syndrome.
  • HbA1c in people with risk factors for diabetes who haven't been screened recently.

TeleTest is often a useful way to get these tests done when a busy in-person visit didn't allow time for them.

How TeleTest approaches this#

TeleTest follows Canadian clinical guidelines (Diabetes Canada, Hypertension Canada, the Canadian Cardiovascular Society, the Society of Obstetricians and Gynaecologists of Canada, Choosing Wisely Canada, and others) and the same evidence-based principles a thoughtful family doctor would.

In practice this means:

  • We order tests that have a clinical reason based on what you tell us in your intake.
  • We follow guideline-recommended intervals for repeat testing. If a guideline says "every three years" and you ask for the test annually, we will explain why we do not bill it as an insured test under the provincial plan - but we will arrange it as a private/uninsured test if you still want it.
  • We will explain our reasoning when we decline to order a test, and we'll point to the guideline.
  • We do not perform "annual full-body lab panels" for healthy people without a clinical reason. We do offer carefully designed metabolic, cardiovascular, and STI panels that are aligned with guidelines, plus optional add-ons (paid privately) for people who want them.

Our goal is to make access easier than the walk-in clinic without abandoning the evidence base.

Common questions#

Does TeleTest limit testing?#

Yes - TeleTest follows guideline-recommended testing intervals. For example, eligibility for diabetes screening uses your intake answers (similar to the CANRISK tool used in family practice). Repeat testing is ordered at the interval Diabetes Canada recommends.

If you want a test more frequently than guidelines support, we can usually arrange it as a private (uninsured) test that you pay for at the lab. STI testing is the main exception - patients with valid clinical reasons can test as often as they want without an interval limit.

Why are some tests not covered if I have provincial health insurance?#

Provincial health plans set lists of tests that are covered when ordered for a clinically indicated reason. Tests that don't routinely change clinical decisions, or that are recommended only for specific groups, fall outside that list.

Examples: vitamin D in an asymptomatic, healthy adult; T3 and T4 in someone with a normal TSH; specialty cardiovascular markers in people without risk factors. These tests are still available as private/uninsured tests if you choose to pay for them.

Does TeleTest test for adrenal fatigue or random cortisol levels?#

We do not. Adrenal fatigue is not a medically recognized diagnosis in the Canadian clinical guidelines (or in mainstream international endocrinology). Random cortisol levels in well people are likely to produce false positives and lead to unnecessary follow-up testing.

If a clinician suspects a genuine adrenal disorder like Cushing's syndrome (which is rare - roughly 5-15 cases per million people in Canada), the recommended tests are different from a simple blood cortisol level. They include 24-hour urine cortisol collection or a steroid suppression test, both of which require in-person coordination and supervision. Random cortisol blood draws are not the right approach for this question.

If you remain interested in adrenal-fatigue testing despite the lack of evidence, this is something some naturopaths offer privately, and is outside what TeleTest provides.

I want a test that TeleTest declined to order. What can I do?#

Two options:

  1. Ask us to arrange it as a private (uninsured) test. Many tests outside the provincial-coverage list can be paid for at the lab directly. We'll write the requisition and the lab will quote the price.
  2. See a family doctor or specialist in person if you want a different opinion on whether the test is indicated. Our refusal to bill a particular test under the provincial plan is not a judgment of you - it's how we keep the platform aligned with the guideline-based standard.
What if I'm being followed for a condition that needs frequent monitoring?#

For conditions that genuinely need close monitoring (for example, INR for people on certain older blood thinners, lipid follow-up after starting a new medication, blood work after starting certain medications), the recommended interval is much shorter and TeleTest follows that. We don't apply general screening intervals to people who are being actively monitored for a condition.

Why does the guideline for some tests change so often?#

Medicine moves with the evidence. As more studies are done, recommendations update. Sometimes a test that used to be common (annual prostate-specific antigen, for example) is no longer recommended for most men. Sometimes a test that was niche (like Lp(a)) becomes recommended once in adult life for everyone. We try to keep our intake forms and templates aligned with the current Canadian guidelines.

Can I get a "second opinion" on a test I already had?#

Yes. If you have lab results from another clinic or country, our clinicians can review them as part of your consultation. Sometimes the right next step is interpretation and reassurance rather than a new test.

Request a TeleTest consultation#

Last reviewed: Spring 2026. Reviewed by Dr. Mohan Pandit, Chief Medical Officer at TeleTest. We review this page periodically as medical guidelines, lab practices, and provincial programs evolve. This page is for general information, not personal medical advice. If you've noticed information that may be out of date or have suggestions, please contact us - we appreciate the help keeping these resources accurate.

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