Vitamin B12 is one of the most requested add-ons on requisitions we see in Ottawa, especially through the winter months when tiredness, pins and needles, or a low blood count send people back to their family doctor. The good news for Ontario patients is that the B12 test itself is an insured service; folate is the one with strings attached. This guide explains what each test measures, who tends to be tested, what OHIP pays for, and how to get the test done at a community lab.
What B12 and folate tests measure
Both are B vitamins your body needs to make healthy red blood cells and to keep nerves working properly. A serum vitamin B12 test measures how much B12 is circulating in your blood. Folate can be measured two ways: serum folate reflects recent intake, while red blood cell (RBC) folate reflects your stores over the previous few months. Your physician or nurse practitioner chooses which, if any, to order alongside a complete blood count (CBC).
Low B12 or folate can lead to a type of anemia where red cells are larger than normal. That is why these tests are often ordered together with a CBC and sometimes with ferritin and iron studies, so that the common causes of anemia can be sorted out from one blood draw.
Symptoms and situations that prompt testing
B12 deficiency builds slowly and its symptoms overlap with many other conditions, which is why a blood test rather than symptoms alone is used to check for it. Providers often consider a B12 level when a patient reports:
- Ongoing fatigue or weakness that has no obvious explanation
- Numbness or tingling in the hands and feet, or balance problems
- A sore tongue, mouth ulcers, or changes in appetite
- Memory or concentration problems, or low mood
- Pale skin or breathlessness together with a low hemoglobin on a CBC
Some people are tested because of risk rather than symptoms. Common examples include following a vegan or largely plant-based diet, long-term use of metformin or acid-reducing medications, previous stomach or bowel surgery, inflammatory bowel disease, and older age, when the stomach absorbs B12 less efficiently. Whether any of these apply to you is a conversation for your physician; the lab only performs what is ordered.
Is a B12 test covered by OHIP?
Yes. Vitamin B12 (fee code L345) appears in Ontario's Schedule of Benefits for Laboratory Services without a listed condition attached, so it is an insured service when an authorized practitioner orders it for a medical reason and you present a valid Ontario health card. Like every other insured blood test, it must be ordered by a physician, nurse practitioner, midwife, or another practitioner authorized under Ontario regulation; a request from a practitioner outside that list, or a test wanted for an employer or insurer, is not insured.
Folate is different
The same Schedule restricts both folate tests. Serum folate (L308) is insured only when ordered by, or on the advice of, a physician with expertise in blood or gastrointestinal disorders. RBC folate (L309) is insured only for patients with low hemoglobin together with a high mean corpuscular volume, or with a suspected gastrointestinal disorder causing malabsorption or suspected malnutrition. Outside those situations the ordering practitioner is expected to mark the test as uninsured on the requisition and the patient pays.
In practice, folate deficiency has become uncommon in Canada because white flour has been fortified with folic acid since 1998, which is part of why the test is no longer routinely covered. If folate is on your requisition and you are unsure whether it applies to you, ask the person who signed it, or ask at our desk before collection. Patient-pay tests are paid at collection and you receive a receipt; ask at our desk if you are unsure.
How to prepare for a B12 or folate test
For most people there is nothing special to do. Follow whatever your requisition says about fasting; B12 and folate on their own do not usually require it, but if they are drawn with fasting glucose or a lipid profile, the fasting rule for those tests applies. Our general preparation guide covers the basics of hydration, medication timing, and what to bring.
- Bring your Ontario health card and your signed requisition, which is valid for six months from the date it was authorized
- Tell the collection staff if you have recently had a B12 injection or take a high-dose B12 supplement; your physician may want to know the timing when reading the result
- Drink water beforehand; a well-hydrated vein makes the draw quicker
- A single tube of blood is usually enough for B12, folate and a CBC together
Understanding your result
B12 is reported in picomoles per litre (pmol/L) against Bio-Test's own reference range. Results near the lower end of the range are common and do not always mean deficiency, so your physician may repeat the test, look at your CBC alongside it, or add a second marker such as methylmalonic acid before deciding anything. If your level is low, treatment and follow-up testing are decisions for your provider, not something to work out from the number alone. When results are released, the Bio-Test app shows them with the lab's range and how they have moved across visits, which is helpful if you are being monitored over time.
Getting your B12 checked in Ottawa
Bring your requisition and health card to any of Bio-Test's 11 patient service centres across Ottawa-Carleton and Eastern Ontario; B12 and folate are collected on a walk-in basis, and you can book a time online if you would rather not wait. Routine chemistry results are usually with your provider within about a business day. If fatigue is the reason for the test, our guide to blood tests for fatigue explains what else is often checked at the same time, and our preparation checklist will help the visit go smoothly.