‘I have a blood test coming up — how should I prepare?’: Ask a doctor

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It’s common for doctors to recommend getting bloodwork following a medical appointment or routine check-up.

Blood tests can identify deficiencies in vitamins or minerals, immune system problems, or signs of infection, as well as whether organs like the liver, heart or kidneys are functioning correctly, according to the University of Pittsburgh Medical Center.

Fox News Digital spoke with a doctor about how to be prepared for your next blood test.

Reasons for blood tests

Doctors may order blood tests for three main reasons: screening, diagnostics or monitoring.

Blood tests can identify deficiencies in vitamins or minerals, immune system problems, or signs of infection, as well as whether organs like the liver, heart or kidneys are functioning correctly. (iStock)

Screenings are unrelated to symptoms and are based on age, risk factors or the last time you were checked, according to Brintha Vasagar, MD, a family physician with Bayhealth Family Medicine in Dover, Delaware.

These tests can screen for things like cholesterol, glucose, HIV or hepatitis C.

Tests for diagnosis are based on the symptoms you have communicated to your physician, said Vasagar.

"We carefully choose bloodwork to help rule in or rule out diseases that might be causing those symptoms," she told Fox News Digital.

Doctors may order blood tests for three main reasons: screening, diagnostics or monitoring.

Blood tests for monitoring could be performed if you already have a diagnosis and your physician wants to make sure the treatments are working and to check for any negative side effects, Vasagar said.

These tests will help your physician make recommendations for changing medicines or lifestyle habits.

What to expect from a blood draw

A technician will take you to a private area and confirm your name and date of birth, Vasagar shared.

After seating you in a chair, the technician will place a tight band around your upper arm to help your veins become more accessible.

Next, the technician will clean the area and insert a small needle to collect vials of blood, the doctor said.

After seating you in a chair, the technician will place a tight band around your upper arm to help your veins become more accessible.  (iStock)

"Some blood tests require different types of testing, which is why we sometimes need several vials of blood," she said.

"When they have what they need, they will remove the needle and hold pressure to help your blood clot."

The technician will label each vial of blood with your identifying information and ask you to verify that it is correct, Vasagar added.

What to do before your blood test

If you have any fear or anxiety about getting blood work, experts recommend discussing your concerns with your health care provider ahead of time.

"They see many people who are anxious about needles and blood, and they can help you calm down," noted the University of Pittsburgh Medical Center.

"Some people like to schedule for first thing in the morning so that their fasting time takes place overnight and is less impactful to their daily routine."

"I usually prepare patients with what we expect the results to be, and when they can expect to meet with me again or receive a call to discuss results," said Vasagar.

"I also tell patients that they will always receive communication about those results, even if they are normal, so if they have not heard anything, they should call."

If you have any fear or anxiety about getting blood work, experts recommend discussing your concerns with your health care provider ahead of time.  (iStock)

You can carry on with your normal routine the day before a blood test. However, if your doctor has asked you to fast, you should avoid eating or drinking anything other than plain water for eight to 12 hours before your blood test, said Vasagar.

"Some people like to schedule for first thing in the morning so that their fasting time takes place overnight and is less impactful to their daily routine," she said.

Fasting is only required for specific blood tests, so it’s important to check with your doctor.

Drinking plenty of water before your appointment will help prepare your veins so that your technician can draw blood more easily. (iStock)

If fasting isn’t required, it’s a good idea to eat and drink before getting your blood drawn to prevent lightheadedness, according to Vasagar.

"If you start feeling dizzy, tell your technician so they can help you lie down and get you a snack and water," the doctor said.

Drinking plenty of water before your appointment will help prepare your veins so that your technician can draw blood more easily, she added.

More smart planning tips

Blood will be drawn from your arm, so dress in a way that allows the technician to access your arm.

"Layering is a great way to stay warm while allowing for easy bloodwork," Vasagar suggested.

Feeling prepared can be a good way to combat anxiety. Make a plan to get to your appointment on time and bring your photo ID and insurance card.

If you are fasting, you can bring snacks, water or coffee to have as soon as you are finished, the doctor advised.

Having a blood test takes just a few minutes and generally isn’t painful, experts agree. (iStock)

If it makes you feel more comfortable, bring a relative or friend along, or listen to music with headphones to distract you from the needle, the same source suggested.

Remember that having a blood test takes just a few minutes and generally isn’t painful, experts agree.

Erica Lamberg is a contributing writer for Fox News Digital.