Most blood tests need no preparation at all. Some do, and getting it right means you won't have to come back for a repeat test.

Do I need to fast?

Only if we tell you to. Tests that often need fasting include blood sugar (glucose) and some cholesterol tests. Fasting usually means nothing to eat or drink except water for 8 to 12 hours before the test. An early-morning appointment makes this easier.

Before the test

  • Drink water. Water is fine even when fasting, and it makes the blood draw easier.
  • Take your usual medications unless we told you otherwise. If you take insulin or diabetes pills and need to fast, ask us how to adjust them.
  • Skip alcohol and heavy exercise the day before, since they can change some results.
  • Wear a top with sleeves that roll up easily.

Bring with you

  • Your photo ID and insurance card
  • A list of your medications and supplements, including vitamins such as biotin, which can affect some tests

Common tests and what they check

  • Complete blood count (CBC): red and white blood cells and platelets, for example to look for anemia or infection.
  • Metabolic panel: blood sugar, kidney function, and minerals such as sodium and potassium.
  • Lipid panel: cholesterol and triglycerides, for heart health.
  • A1C: your average blood sugar over the past 2 to 3 months, used to check for and follow diabetes. It doesn't need fasting.
  • Thyroid (TSH): how well your thyroid gland is working.

If you're nervous about needles

Tell the staff before they start. Sit or lie down, look away, and breathe slowly. Drinking water beforehand and eating a snack right after (if you were fasting) helps many people feel better.

Quick answers

  • Can I drink water? Yes. Plain water is fine, even when fasting.
  • Can I drink coffee? Not if you're fasting. Even black coffee can change some results, so have it after the test.
  • Can I brush my teeth? Yes. Just don't swallow the toothpaste, and skip gum and mints.
  • How many hours without food? Usually 8 to 12 hours, but only if we asked you to fast. Fasting overnight with a morning appointment is easiest.
  • Can I smoke? It's best not to smoke on the morning of the test.

After the test

You can eat and go back to your usual day right away. If you feel faint, sit down and tell the staff. We will contact you about your results, and we're happy to explain what they mean.

Our patients can have blood drawn right here at the clinic lab. Our lab is administered by PacLab.