Wednesday, September 21, 2016

Wednesday Factoid: Blood Type

Today's Wednesday Factoid is: Do you know your blood type?

Yes! My blood type is O positive.

Let's make this journal entry interesting with a) an explanation of what O positive means; and b) the tale of how I found out my blood type!

What does O positive mean?

O is the blood type. Lots of people know blood has "types," but many people don't know what that means. O is actually more like 0--like zero. It means you do not have either A or B antigens on your red blood cells. People who have Type A blood have A antigens on their red cells. People who have Type B blood, you guessed it, have the B antigens. People with AB have both. And people with O have neither. 

You get your blood type from your parents--from the combination of your parents, actually. You can't exactly inherit one parent's or the other's so much as you inherit a mixture of them. If both your genetic parents are O, you're O. If they're both AB, you could be A, B, or AB. There are all kinds of combinations. 

The "positive" or "negative" bit is the Rh factor. Rh is a third antigen you either have or don't.

If you have A, B, and/or Rh antigens, your blood can only be donated to someone who also has what you have. But if you do NOT have one or more of them, someone who DOES can still receive your blood. That's why O negative people are the "universal donors" and AB positive people are "universal receivers." If you're O negative, you're the most likely to have issues with blood that has something in it you can't process--because if you receive blood with an antigen your natural blood doesn't have on the red cells, you can get curdling that makes your blood not work like blood, and then you'll die and stuff.

Did you know that in some places, blood types are likened to personality types? It's kinda like the zodiac. My type supposedly has good self-esteem and motivation, tends to be optimistic, and has good intuition, but also might be over-critical, selfish, withdrawn, or too focused on their work. I guess I could see that fitting somewhat. :P

How did I find out my blood type?

Funny story! I was taking an anthropology class, and one of the subjects was about groups of humans and how they developed different blood types that originated from different parts of the world. The class was mostly a lecture class, but it had a lab component once a week. One week, the lab experiment was testing our own blood to find out what kind we had!

You could opt out if you wanted to, but you still had to do the experiment. So if you didn't want to use the provided instrument to stick yourself and get some blood (the same kind of thing diabetic people use to get theirs), you could test some sample blood. But I think everyone in my session wanted to do their own. Everyone was following the instructions fine and getting blood to put on their slides. But I couldn't get any blood to come out when the thing stuck me.

The pinprick hurt, but nothing came out. And it wasn't a problem that could be caused by not pushing hard enough or being squeamish; when you pressed it, it came out and stuck you, no questions asked. I did this a total of TWELVE TIMES on various fingers. Nothing I did could get any blood out. My TA was kinda baffled, because you could see the thing was going off.

Finally the TA suggested maybe I just have really low blood pressure and therefore don't bleed easily. While everyone else was testing their blood with antigens that would cause reactions to help you determine what kind of blood you had, I was instructed to run around the classroom multiple times and then stick myself again. And that worked.


Testing involved taking three drops of your own blood and testing one for a reaction to A antigens, one for a reaction to B antigens, and one for a reaction to Rh antigens. If you dropped A on a sample and it coagulated, that meant you had B antigens in your blood reacting to it. If you dropped B on a sample and it coagulated, it meant you had A antigens in your blood. Same for Rh--if it reacted, you were Rh positive, and if it did not react, you were Rh negative. My only clumping reaction was on the Rh slide, so that implies I have O positive blood.

This is the work of a college student in an imperfect lab experiment, though. So I would want to get it tested officially if I needed a transfusion or something.