Your Step-by-Step Guide to Donating Blood

What if we told you that you could save up to three lives in just one hour? Want in? Schedule an appointment to give blood today, and know what to expect at your visit with our guide for how to donate blood.

Blood transfusions are essential for surgeries, traumatic injuries, chemotherapy treatments and chronic illnesses like sickle cell disease, according to the American Red Cross. That's why giving a unit of blood is one of the easiest and most effective ways you can help out people in need.

If you're a first-time donor, consider this your crib sheet. We've got all the info you need to know before, during and after this safe and simple procedure.

Here's a step-by-step guide for what to do before your appointment:

First, the basics: You have to weigh a minimum of 110 pounds and must be at least 17 years old (or 16 with parental consent), according to the American Red Cross.

You should also be feeling healthy. Stay home if you have the flu, a cold, a productive cough or a fever over 99.5 degrees (allergies are OK). Certain diseases — including hepatitis, some STIs and specific kinds of cancer — might affect your ability to donate, so check the American Red Cross website for details.

Although most medications won't influence your eligibility, there are exceptions. For example, if you're taking oral antibiotics for an infection, you should hold off on giving blood until you've completed treatment, per the American Red Cross. (For injected antibiotics, you need to wait 10 days post-treatment.)

There are other meds, as well as a few vaccines (though not the COVID-19 vaccine), that preclude donation — an alphabetical list is available from the American Red Cross or your local blood center's website.

Other considerations that might require deferring your donation include:

• You have low iron
• You've recently traveled to a malaria-risk country
• You participate in certain types of sexual activity
• You recently got a tattoo
• You're pregnant or have recently given birth

People who have used IV drugs are not eligible for donation.

For answers to more FAQs, check out the donor section of the America's Blood Centers' website.

You can search for a blood donation center or drive near you and schedule an appointment to give using our interactive map or by visiting RedCrossBlood.org, AmericasBlood.org or AABB.org.

Even though it only takes about 10 minutes to draw a unit of blood, set aside an hour for the appointment so you have time to answer the screening questions, get a mini physical (more on that later) and then recover in the refreshment room afterward.

The day before your appointment, forgo any partying (alcohol dehydrates you) and get a good night's sleep. This helps prevent adverse reactions like dizziness or fainting, according to the American Red Cross.

When you get dressed, choose comfortable clothes with short sleeves or sleeves you can roll up past your elbow so the technician can easily insert the needle.

An hour or two before your appointment, drink an extra 16 ounces of water, per the American Red Cross.

"A unit of blood is 500 milliliters, which means we are extracting the equivalent of two soda cans' worth of fluid from your body," says Yvette Miller, MD, executive medical director of the American Red Cross. "If you're not well hydrated, you might feel lightheaded."

Just avoid downing an entire bottle of water immediately before your appointment — that way, you won't have to pee in the middle of the procedure.

While it's fine to have a cup of coffee beforehand, keep your caffeine intake in check.

"Caffeine increases your heart rate, and if your heart rate is too high, you won't be able to donate," Dr. Miller says.

You should also eat a small, well-balanced meal to keep your blood sugar stable and prevent nausea.

Fatty foods can make it difficult to perform the pre-donation safety screening on your blood (we'll get to that in the next section), so skip the burgers, fries and ice cream. And chow down at least an hour beforehand to give yourself time to digest.

Bring a government-issued ID — like a driver's license, passport or a school photo ID if you're in college — as well as a list of medications you're taking, per the American Red Cross.

Bring along something relaxing to do while your blood is drawn, like a book, or your (fully charged) phone and a pair of headphones so you can listen to music or a podcast, watch a movie or call a friend.

Here's what to expect at your appointment:

When you arrive at the collection center, you'll sign in, show your ID, give your address and read some information about eligibility and the donation process, according to the American Red Cross.

Next, you'll be asked a series of questions, either via an online form or in a private interview, to determine if it's safe for you to donate and if your blood is safe for others.

The questionnaire will touch on your health, travel history, medications, sexual activity and more. It's important to answer all of the questions honestly.

Next, a staff member will take your temperature, measure your pulse and blood pressure and test your hemoglobin levels using a finger stick.

Here's what to expect during the donation itself: While you're lying down or seated comfortably, a staff member will examine your arms to find a suitable vein, clean the area and then insert a new, sterile needle.

"If you're anxious, look away and take a few deep breaths to calm down," Dr. Miller says. Your phone is also a great distraction to take your mind off things.

Although you'll feel a pinch right when the needle goes in, it shouldn't hurt afterward. Let an employee know if you're experiencing any pain. "Also, tell someone if you're feeling lightheaded," Dr. Miller says. "Elevating your legs or having a drink or snack should help."

In addition to the pint of blood for donation, the collection center will also fill some small test tubes to check your blood for infectious disease.

"Once the procedure is complete, a staffer will place a pressure bandage on your arm," says Ruth Sylvester, director of regulatory services for American's Blood Centers. You'll need to keep the bandage on (and dry) for the next five to six hours to help the area heal.

Once your blood donation is complete, here's how to recover:

When you're done, a staff member will help you stand and you'll be asked to spend 15 minutes in the canteen to rest up. Grab a seat and a drink or two to replenish your fluids, per the American Red Cross, and let a staff member know if you feel dizzy, nauseous or otherwise unwell.

Before you leave, you'll be given a post-donation information sheet with basic care instructions, symptoms to watch for and a number to call in case you have a problem.

For the rest of the day, avoid heavy lifting, strenuous exercise and too much alcohol, per the American Red Cross. Eat well-balanced meals and drink plenty of fluids.

People seldom experience symptoms post-donation. Still, here's what to do if you're feeling nauseous or dizzy after donating blood: "Lay down and elevate your legs, or sit with your head between your legs," Dr. Miller says.

About an hour after leaving the collection center, Dr. Miller suggests removing the elastic wrap from your bandage and gently cleaning the area around the bandage so it doesn't get irritated. You can take off the bandage itself after a few more hours.

"If it starts bleeding again, or you notice swelling or bruising, apply pressure and lift your arm straight up over your head for several minutes," Sylvester says. "An ice pack can help relieve discomfort."

Someone in the U.S. needs blood every two seconds, according to the American Red Cross — but there's not always enough supply to meet that demand. Be a part of fixing that!

You're eligible to donate whole blood again after eight weeks (56 days), per America's Blood Centers, so now that you know how to donate blood, get your next appointment on the calendar ahead of time.