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What Everyone Should Know About Blood and Blood Donation

FAQs About Donating Blood


In the days following November’s tragic school bus crash, lines to donate blood stretched out the doors of area blood banks. Donors with blood type O- were fast-tracked to the front. From cancer patients to trauma victims, hundreds of people in our city need blood transfusions every day. But do you really understand your blood and how donating blood saves lives?


Woman donating blood in busy hospital donation bank

By Andrew Shaughnessy


Blood Types, Explained

Blood is divided into four major blood types: A, B, AB, and O. These are determined by specific sugars located on the surface of your red blood cells (RBCs). Blood is further classified by the Rh factor, which is determined by a specific protein on the surface of your RBCs. If you carry that protein, you are Rh positive (+). If you don’t, you are Rh negative (-). Read on to learn why classifying these types is so important.

Compatibility, Explained

When a red blood cell transfusion takes place, the recipient and the donor must have compatible blood types. If an incompatible blood type is transfused into a person’s blood stream, the recipient’s immune system will attack it. A matching type is always compatible. But certain blood types can give to, or receive from, different classifications. Type AB+, for example, which is found in 3.4% of the population, is known as the “universal recipient” because people with this type can receive any type of red blood cells. In contrast, type O-, found in 6.6% of the population, is known as the “universal donor” because red blood cells from these donors can be given to patients of all blood types. This versatility is what makes it so valuable and critical in emergencies.



blood type donor compatibility chart



Dr. Liz Culler Medical Director, Blood Assurance chattanooga
Dr. Liz Culler Medical Director, Blood Assurance

Learning Your Blood Type

Whether you are just curious or need to learn your blood type for medical purposes, the only reliable way to learn your blood type is to get a blood test. You can request a blood test through your primary care physician, local health clinic, or when you donate at a blood center. If you donate at the local blood bank, Blood Assurance, your blood type will be determined by the end of the next business day. Simply call the main number at 423.756.0966 or ask at your next donation.

Why Blood Matters

“Donated blood goes to patients with long-term medical conditions like cancer,” explains Dr. Liz Culler, medical director at Blood Assurance. “It also goes to patients undergoing planned or emergency surgery.” For every patient who needs a transfusion, many donors are needed. There is currently no artificial substitute for blood – that’s why the need for donation is so great. “Blood Assurance services more than 70 health care facilities in our surrounding area,” says Dr. Culler. “Your donated blood will be transfused to someone in need right here in our community.”

How Much You Give

The average adult has about 10 pints of blood. When you give blood, you typically donate one unit, or about one pint of blood. How much a patient needs depends on their condition. For perspective, a newborn baby in neonatal intensive care may require one to four units during hospitalization, whereas a victim of a car accident may need up to 100 units. “In the case of an emergency, we’re talking about needing 60 or 70 people to donate blood to keep one person alive,” says Lecia Guill, blood bank supervisor at CHI Memorial.

blood donation questions and answers chattanooga

Lecia Guill, BS, MT (ASCP) Blood Bank Supervisor, CHI Memorial chattanooga
Lecia Guill, BS, MT (ASCP) Blood Bank Supervisor, CHI Memorial

What to Know Before You Donate

For the best experience, get a good night’s sleep, eat three healthy meals (low fat, high protein), and drink lots of non-caffeinated beverages in the 24-hour period before donation. “Hydration will prepare your veins, making them full and plump,” says Guill. Remember to bring two forms of identification and wear clothing with sleeves you can roll up above the elbow. If you can, come prepared with your travel history, medical history, and a list of medications.

Tests and Requirements

If you are 16 or older, weigh at least 110 pounds, and are in good health, you are generally eligible to donate blood. The process begins at the donation center with basic donor identification and registration. Next, you will have a mini physical that checks your temperature, blood pressure, pulse, and hemoglobin levels (to ensure you don’t suffer from anemia). You will also need to answer questions about your medical and travel history, as well as any medications you are on. “The good news is, most medications will not delay your donation,” says Guill.



routine blood donation chattanooga

How Donation Works

Once you’re cleared, the blood donation process itself takes eight to 10 minutes. Staff will clean an area on your arm and insert a new, sterile needle into the vein – a quick and easy process. Then, you just sit back and wait. As you donate, Dr. Culler recommends pushing down one foot like you are pressing on the gas pedal in your car. Hold for five seconds, then release, and do the same with your other foot. “This forces the blood away from your trunk and up to your head, preventing reactions,” she says.

Tips for Immediately After

Once the bag is filled, you will be bandaged up and given snacks and fluids to help replenish your body. Stand up slowly, and plan to stay in the designated recovery area for at least 15 minutes. You’ve essentially had a small blood loss, and your body needs a little time to adjust. Lay back, drink some fluids, and enjoy a snack. Start to finish, the whole process can take more than an hour.

Tips for the Next 24 Hours    

Do your best to stay hydrated and avoid alcohol for the next 24 hours. You’ll also want to avoid any heavy lifting or intense exercise. To prepare your body to replace the blood you donated, eat foods rich in iron (like spinach, meat, and beans), folate (leafy greens and orange juice are solid bets), and riboflavin (eggs, peas, nuts, and dairy products).

How Recovery Works

Once you donate, your body has an amazing capacity to replace the cells and fluids you’ve lost. It replaces lost plasma (the liquid part of blood) in the next few days. “You can speed this up by drinking lots of fluids,” says Dr. Culler. It replaces the protein part of the blood over the next 28 days and the red blood cells in the next 56 days. This is why you must wait at least eight weeks between red cell donations.

Coping with Nerves

If you want to donate, but find yourself nervous (or terrified!) at the prospect of needles, take a deep breath. Mindset is key. First, educate yourself on donation, so you aren’t surprised (you’re off to a great start by reading this article). Second, distract yourself by reading a book, listening to music, or talking to a friend. Finally, stay focused on the real and tangible impact you are making. “The initial stick may be uncomfortable, but the benefit to people in our community is worth it,” says Guill. Plus, it’ll be over before you know it!

Now is a Great Time

January is National Blood Donor Month, observed for more than 30 years to increase blood donations in winter. Collecting enough blood to meet patient needs tends to be more difficult during the colder months. As weather or seasonal illnesses keep more people at home, attendance at blood drives and donation centers dwindles. “Snow and road conditions can make these months extra tough,” says Guill. “Even missing a day or two of collection significantly impacts inventory.” Type O-, in particular, is in high demand. If you’re ready to help your community by donating blood, there is no better time than the present.

How and Where to Give

If you’re ready to donate blood, check out bloodassurance.org/where-to-donate or call 423.756.0966 to find a blood center near you. The Chattanooga area has five donor centers and many mobile blood drives. Whether you are downtown, or out in Fort Oglethorpe or Hixson, finding a convenient place to donate is easy.

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