In Ontario, the short answer is yes: for most blood tests you need a lab requisition before a laboratory can draw and process your sample. A requisition is the signed order that tells the lab which tests to run and who requested them. Understanding how requisitions work, who can write one, and how long they stay valid can save you a wasted trip and help you get the bloodwork you need without delay.
What is a lab requisition?
A requisition is a form completed by a healthcare provider that lists the specific tests to be performed. It includes your identifying information, the ordering provider's details, the tests requested, and any special instructions such as whether you need to fast. The lab uses it to confirm what was ordered, to route your results back to the right provider, and to determine whether a test is insured under OHIP or billed to you. Without a valid requisition, a lab generally cannot collect your sample for most tests.
Who can order a blood test in Ontario?
Lab tests must be ordered by an authorized provider. In Ontario that includes:
- Physicians (family doctors and specialists)
- Nurse practitioners
- Midwives, for tests within their scope of practice
- Naturopathic doctors, for a defined list of tests per the College of Naturopaths of Ontario
Patients cannot self-order most tests. If you don't have a family doctor, a nurse practitioner at a walk-in clinic can often assess you and provide a requisition when testing is appropriate.
How long is a requisition valid?
A standard lab requisition is generally valid for about six months from the date it was signed. As long as it hasn't expired, you can usually use it whenever you're ready, so there's no need to rush in the same day it was written. If a provider wants ongoing monitoring, they can write a recurring or standing order that specifies the frequency and number of visits, such as "x3, q3 months" (three times, every three months). These standing orders let you return for repeat bloodwork over a longer period without needing a new form each time.
What if you've lost or expired your requisition?
It happens. If your requisition is more than six months old, or you can't find it, the lab cannot simply reissue it because only the ordering provider can authorize the tests. Here's what to do:
- Contact the office of the provider who ordered the tests and ask them to re-send or re-issue the requisition. Many clinics can fax or email a copy directly to the lab.
- If the original provider is unavailable, book a visit with a walk-in clinic or nurse practitioner, who can assess whether the tests are still appropriate and write a fresh requisition.
- Check whether you have a recurring order on file from a previous visit, as it may still be within its valid window.
When in doubt, call us before you come in and our staff can tell you whether the requisition we have on file is still current.
Walk-in clinics as a route to a requisition
If you don't have a regular family doctor, walk-in clinics and nurse-practitioner-led clinics are a practical way to get assessed and, when warranted, receive a requisition for bloodwork. Bring a list of any symptoms or concerns, along with your Ontario health card. Once you have a valid requisition in hand, you can bring it to any Bio-Test location. To learn how to get ready for your visit, see our guide on how to prepare for a blood test.
Getting your blood test done at Bio-Test
Once you have a valid requisition, most bloodwork at Bio-Test is walk-in and first-come, first-served, with no appointment needed, though you can book ahead if you prefer. Bring your Ontario health card and your signed requisition. We have 11 locations across Ottawa-Carleton and Eastern Ontario, and you can book online through our patient portal or find your nearest lab. Home visits can be arranged by request for a fee.