Fasting before a blood test in BC: needed for fasting glucose, not for cholesterol

In BC, you only need to fast before a few blood tests, chiefly fasting glucose: at least 8 hours, water only. Cholesterol, Apo B, HbA1c, ferritin and vitamin D don't need a fast unless your clinician asks.

BC's standard requisition says no lipid panel needs a fast, though a clinician may ask for 10 hours in select cases, such as a history of triglycerides above 4.5 mmol/L. HealthLink BC's cholesterol page still mentions 9 to 14 hours, so follow the instruction on your own requisition.

Getting the fast right matters most for glucose, a key test for prediabetes (blood sugar above normal but below diabetes). In a US survey, 84% of adults with prediabetes didn't know they had it, and a glucose test in the past three years was the strongest predictor of knowing (Wang et al., 2025).

Which blood tests need fasting?

What can you have while fasting?

Morning draws, like Numia's at-home visits, put most of the fast overnight.

• Water: yes.
• Coffee, tea, gum, smoking, exercise: no. LifeLabs means "not even black without sugar."
• Alcohol: none for 24 hours before a lipid test (HealthLink BC).
• Medications: keep taking them unless your prescriber says otherwise. With diabetes, ask whether to take morning insulin or diabetes medicine after the draw.

Do supplements affect blood test results?

Some do. Health Canada asks you to tell your doctor if you take more than 30 µg of biotin a day, because high doses can skew thyroid and troponin results. Hair, skin and nail products often contain it, so mention it when you book Numia's Thyroid Basic or Fatigue Panel. Don't stop a prescribed medication for a test without your prescriber's advice.

Where does Numia fit?

Numia Health, a physician-ordered, at-home blood testing service in Greater Vancouver, gives each panel's fasting instruction when you book. The Fatigue Panel needs an 8–12 hour fast, water only. Electrolytes and Basic Nutrients need none, and the Cardiac panel page says non-fasting testing is acceptable for most routine lipid checks. For Thyroid Basic, Weight Loss Monitoring, Male Hormone and Female Pre-Menopause, follow your booking instructions. After a licensed Canadian physician approves your requisition online in about 3 minutes, a clinician draws your blood at home; results arrive in plain English in the Numia app in 7 days. An optional wellness consultation is available, and Numia is an HSA-eligible service.

Frequently asked questions

What does HealthLink BC say about fasting before a blood test?

Nothing but water for at least 8 hours before a fasting glucose, and 12 hours before an iron test. Numia gives each panel's instruction when you book.

What are LifeLabs' fasting instructions?

If you're told to fast: at least 8 hours for glucose and 12 for lipids, water only, with no coffee, tea, gum, smoking or exercise. LifeLabs' BC vitamin D and testosterone tests don't require fasting.

Do I need to fast for a cholesterol test in BC?

Usually not. BC's requisition doesn't require it for lipids, though a clinician may ask for 10 hours. Numia's Cardiac panel page says non-fasting testing suits most routine lipid checks.