I previously wrote how I decided to donate blood for the first time and live tweeted the hilarity of my nervousness during the event. Several weeks after that, I got my blood donor card. I was curious to see it because I wanted to know what my blood type is. When I got the card, I found out that I am O-negative (O-). I am a universal blood donor. I assume I have now been put on that blood donor hit list when the blood bank gets low. My blood donor card came complete with a photo of an infant’s foot to take home the fact that O- blood is often used to help newborns as well as trauma victims before their blood can be typed.
Why am I a universal blood donor? There are eight major blood types. The type refers to antigens present on the red blood cells. I say eight major blood types because there are actually more blood types than that based on various antigens found on the red blood cells, but when you donate blood, they type you based on ABO antigens and the Rh factor. With ABO antigens, there is O, A, B, and AB with O meaning the absence of A or B. You can only accept blood from someone who has antigens that you have on your own red blood cells or to say it another way, someone who does not have antigens that you don’t have. With Rh factor, you have that antigen or you don’t, so if you have it, you are Rh+ or Rh-. If you are +, then you can accept from people who have it or those who don’t. If you are -, then you can only accept from that who don’t have it. You can’t receive blood from someone with an antigen on their red blood cells that you don’t have or your immune system will quickly react very badly to that foreign antigen being in your body. If you still find this confusing, it works out like this.
| Blood Type | US Population* | Can donate to: | Can receive from: |
| O- | 9% | Everyone (O-, O+, A-, A+, B-, B+, AB-, AB+) | O- |
| O+ | 39% | O+, A+, B+, AB+ | O-, O+ |
| A- | 6% | A-, A+, AB-, AB+ | O-, A- |
| A+ | 31% | A+, AB+ | O-, O+, A-, A+ |
| B- | 2% | B-, B+, AB-, AB+ | O-, B- |
| B+ | 9% | B+, AB+ | O-, O+, B-, B+ |
| AB- | 1% | AB-, AB+ | O-, A-, B- |
| AB+ | 3% | AB+ | Everyone (O-, O+, A-, A+, B-, B+, AB-, AB+) |
*The population data is based on information from AABB.
Thus, as someone who is O-, I am a universal blood donor, but I only can receive blood from other O- people. AB+ people are universal blood recipients and can receive blood from anyone. All of this shows the importance of blood typing people before they know they will need blood. It also shows why on tv and the movies, whenever someone is rushed into an emergency room and needs blood, the medical staff scream for O- blood (plus it makes for drama). Until they have time to type the patient’s blood, they can safely give the patient O-. Thus the information on my O- blood donor card that informs me it is particularly important for me to donate blood for those emergency room patients and of course the babies whose feet are on my card. It’s a nice little guilt trip to get me to keep donating.
The guilt trip worked. I gave blood again yesterday. It went a little better than last time because I wasn’t quite as nervous, but I admit I was still nervous. Unfortunately it didn’t go quite as well as it could. Last time, I used my left arm, but because I use the computer mouse with my left hand but write with my right hand, I decided to have them use my right arm this time. Evidently I have better veins in my left arm. The phlebotomist poked my right arm and couldn’t get the needle in well or something. He asked if he could take it out, which I readily agreed to because it was causing me pain. I switched chairs. He poked my left arm and found a good vein. I guess I need to find out how to build better veins in my arms. I survived. I felt fine afterwards, and I saved another life. That’s what really important.
I’m in the O- camp as well. It’s a little frustrating for me, given that I can’t donate due to hepatitis antibodies. A good friend of mine who is AB- donates as often as she can due to a lesser availability of her blood type. I knew O types were more compatible with others, but I had no idea the degree to which O- could be used.
The list you posted is fantastic! We need more people with compatible blood types donating blood, especially around the holidays when there are statistically more accidents. I usually encourage people to donate once each month and to call their local blood banks to see if they are looking for donations to make sure there is always a fresh supply. Great article, thanks!