Here's What to Expect During a Blood Draw

By InsideTracker, December 14, 2023

What to expect during your blood draw

Even if you don't mind needles, blood draws tend to bring up feelings of uncertainty, confusion, and sometimes worry. These feelings are normal and the goal of this article is to help you feel prepared for your blood draw and know what to expect when it’s time for your appointment.

Come to the blood
test prepared 

The first step to having a smooth blood draw process is to come prepared. 

You should: 

  • Fast for 12 hours: All InsideTracker plans require that you fast for 12 hours before your blood draw. This means no food, no alcohol, and no beverages besides water or black coffee. 
  • Drink water: It is important to be properly hydrated before your test to help the blood draw go more smoothly, as it’s easier to find veins and complete the draw when a person is well-hydrated.
  • Continue medication use as recommended by your physician: Please follow your physician’s recommendations when it comes to your specific medications (both prescription and over-the-counter). 
  • Dress comfortably: The blood draw technician—or phlebotomist—will need access to your arm for the draw. Consider wearing a top you are comfortable in that allows for ease of access.
  • Bring necessary materials: you will need to bring your printed lab slip and a valid photo ID for InsideTracker blood draws at Quest Diagnostics. The lab slip for your blood draw will be sent via email after the purchase of your InsideTracker plan. If you instead opted for a mobile blood draw, instructions on the materials that will either be shipped to you or that your phlebotomist is responsible for will be provided via email. 

You should not:

  • Drink alcohol within 24 hours of the test: Alcohol the night before can affect blood sugar (glucose) and fat (triglyceride levels) so it’s best to avoid drinking alcohol before the blood draw. 
  • Exercise intensely 48 hours before your test: Exercise can also alter certain biomarkers, particularly ones related to muscle breakdown and recovery. It is recommended that you do not engage in strenuous exercise for two days before the blood test.
  • Take supplements within 24 hours of your blood draw: It’s best to hold off taking any supplements right before your blood draw. Supplements can acutely impact some of your biomarkers, but you can resume your supplement routine after the blood draw.
  • Test if you are sick or taking antibiotics: If your body's fighting an infection, your test results may be different from your normal levels, providing an false baseline to track against for certain biomarkers. While most antibiotics will not impact blood test results, amoxicillin may cause falsely high glucose levels. Amoxicillin usually leaves the body within 24 hours, but we recommend waiting 48 hours after your final dose to test.


What to expect when you get your blood drawn

After you order an InsideTracker plan, it is time for you schedule your test at a local Quest Diagnostics lab or select the mobile blood draw experience for a phlebotomist—a health professional who’s trained to draw blood—to come directly to your home. No matter where your blood draw takes places, the actual blood collection process is similar.

Here’s what you should expect at the time of the draw.

  1. The phlebotomist will likely ask if you have a preference for what arm to have the blood drawn from, and you will be asked to expose that arm (here’s where that comfortable clothing comes into play). 
  2. Then, they will then place a tourniquet on your arm, this is usually a band of rubber that is tied around your arm. A tourniquet is placed to stop the circulation of blood, making it easier for the phlebotomist to find the vein.
  3. Once the tourniquet is in place, the phlebotomist will identify a vein on the inside of the elbow. If they can’t identify a good vein to access they may try the other arm.
  4. That area is then sanitized before the needle is inserted.
  5. The needle is inserted.
  6.  Next, the tourniquet is removed to improve blood flow for the collection. 
  7. The blood collects in test tubes. The number of test tubes needed depends on what tests are being run, but will typically range from 3 to 9 tubes. While this may seem like a lot of blood, it is much less than what is drawn for a blood donation.
  8. Once the necessary amount of blood is collected, the phlebotomist will remove the needle and place gauze on the insertion site while applying pressure.  
  9. Lastly, they will then place a bandage over the site in case there is any additional bleeding.

What to expect after the blood draw 

While having your blood drawn is a routine procedure, there is always a possibility of minor side effects after a blood draw. The good news is that if you do experience side effects, they should resolve quickly. These side effects can include

  • Minor bleeding after the needle is removed
  • Bruising around the insertion site
  • Soreness around the insertion site
  • Possible lightheadedness 

To help prevent or lessen the side effects it is recommended that you:

  • Keep the bandage on the recommended amount of time 
  • Break your fast! If you have experienced any lightheadedness or fainting, bring a snack to eat after your blood draw and let the phlebotomist know if you are not feeling well
  • Resume exercise only when you feel ready (it can be that day if you feel up for it)


Keep calm, come prepared, and take control of your health

While the blood testing process can be daunting, it doesn’t have to be something you fear. Knowing what to expect and how you can prepare for your test can help calm some of those nerves. And the more you get your blood draws, the more comfortable you may become. We recommend routine blood testing about two to four times a year (every three to six months) to monitor your biomarkers as they shift in response to lifestyle changes. 

Other things you can do to relieve some of those nerves include taking some deep breaths, getting your blood draw done with a friend or family member, or talking with your phlebotomist about your concerns.


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