Basic Blood Grouping and Rhogam

[AcidFast]

To explain the system of Basic Blood grouping, we must first understand basic immunological reactions by the body.

Antigen = anything that causes an immune response by the Human body. Antigens are mainly a reference to chemical compounds on the outside of a cell's surface. They are usually unique to certain cells, and is mainly how the body identifies certain infectious bacterias.

Antibody = a chemical compound created by the Human body's white blood cells which attaches itself to certain antigens and initiates an immune response by the body. Some Antibodies are non-specific (attaching to ANY antigen the body does not recognize) and others are specific (created by the body to battle specific antigens). There are different types of antibodies, and they come in different sizes. IgG is the smallest, and IgM is the largest (IgM being, simply, 5 IgG molecules attached together). Specific antibodies are generally referred to by the name of the antigen they are specific for, preceded by "anti-" .

Primary and Secondary response = The primary response happens when the body encounters an antigen it doesn't recognize. Non-specific antibodies in the blood stream will attach themselves to the unknown antigen, 'flagging' it for destruction by the WBCs (White Blood Cells). Certain WBCs (there are many different types of WBCs, and they all have different jobs) will break down the antigens on the surface of the unknown cell, and create antibodies specific for the cell. This takes some time, but the next time the body encounters the same antigen, it will dispatch it much quicker (secondary response).

This is why you only seem to get things like Chicken Pox and Measles once. The first time, you get sick while your body is creating the correct antigens. After that, you may get it, but it is gone before you get really sick because the secondary response is much quicker, and you may have what seems to be a cold for a day or two, and then you are better.

RBCs (red blood cells) are cells like any other, and have their own antigens. The antigens that are in the most frequency on the RBCs surface are the ones that we are concerned about, because the amount of antigens determines the strength of the immune response. The two antigens that are in the highest frequency on the RBCs surface are called A and B. The only other one we will be concerned about is known as D (among many other names, "Rh" being one). It is in much less frequency than A and B, but in enough quantity to cause some problems we need to be aware of.

RBCs come in four types of ABO group, depending on which antigens are present one the surface. Type A has A, Type B has B, Type AB has both, and Type O has neither. The positive and negative part of a blood type is determined by the presence (positive) or lack thereof (negative) of the D antigen.

The breakdown of blood types, from most prevalent to least is this:

A and O Pos
B Pos
AB Pos
A and O Neg
B Neg
AB Neg

A and B blood types have a strange quality: The body makes antibodies to the opposite bllod type automatically. A person with blood type A has the A antigen on their RBCs, and also has the Anti-B antibody in their bloodstream. A person with blood type B has the Anti-A antibody in their bloodstream. A person with blood type AB has neither antibody, and a person with blood type O has both.

So, lets review:

Type A has the A antigen and Anti-B antibody
Type B has the B antigen and Anti-A antibody
Type AB has A and B antigens, and neither antibody
Type O has neither antigen, and Anti-A and Anti-B antibodies

When we give blood, we do not normally give 'whole blood'. We give a suspension of Packed Red Blood Cells (PRBCs). There is mostly RBCs, and almost no plasma (the liquid part of the blood), therefore almost no antibodies. When we give blood to a patient, we are concerned about giving the wrong type in that the recipient of the blood may have an immune response that destroys the RBCs we transfuse into them.

If we were to give an incompatible ABO type unit, the antibodies of the recipient would attack the cells of the donor unit, destroying them, and clumping them together, effectively clogging up the bloodstream with little clumps of RBCs. If we were to transfuse an incompatible ABO type, it could kill a person within 15 minutes or so, with nothing we could do to stop the process.

Of course, the main concern here is the ABO part of the type. D is a factor, but for a different reason. The D antigen is not normally present in the blood, for either positive or negative blood types. Anti-A and Anti-B are the only ones that are already there (secondary response) and will clump and destroy RBCs very quickly.

With D or Rh, a person who is negative for the antigen has the ABILITY to create the antibody to it. This is a primary response, however, and doesn't normally affect transfusions because the primary response takes too long. Also, the relative infrequency of the antigen on the RBC surface causes a response of MUCH less strength than the ABO response, and will not kill a person normally. Again, we try to give blood that is Pos/Neg compatible, but for a different reason. Therefore, a person who is Negative has the ABILITY to create Anti-D, and a person who is Pos does not have this ability (the body knows that it cannot ever create this antibody). So, we try not to give Pos blood to a Neg patient (the creation of the Anti-D antibody can cause problems later on, but not immediately), but we can if its all we have (its not going to kill them).

Ok, I have to go, more on this later.

Are there any questions?

[Samadhi]

Methinks this should be elsewhere. Off to SAC you go.

[Quailman]

[Samadhi]

I'm sure even 99% would not be deadly. And it's certainly closer to 99.99%

[Courk]

That makes so much sense now! I always wondered why AB was the universal receiver and O was the universal donor. It didn't make sense why O wou ldn't be able to receive any kind of blood if it could be given to any kind of blood.

*waits eagerly to read more*

[AcidFast]

Quailman:

Originally posted by Quailman:

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I presume that the 'processing' that occurs after an individual donates a pint of blood includes separation of the plasma and platelets and that these might be used for other purposes. Do you ever administer these, and if so, what conditions would warrant that you transfuse them?

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When blood is collected whole (there is a method of platelet collection called "Platelet Pheresis" that involves drawing the blood, spinning it down, removing the platelets and retransfusing the blood, all within a closed, sterile system, of course), it is spun down in a centrifuge (yep, bag and all) and the plasma is actually squeezed out the top of the bag. The other components are mainly for people who are having trouble with their blood clotting. There are many coagulation factors in the blood, and they get exhausted when someone is bleeding badly. That is usually when it is called for to transfuse Platelets, Fresh Frozen Plasma (FFP) or Cryoprecipitate (Cryo). There are other factors that can be transfused, but they are usually chemically seperated from the blood or manufactured. I don't deal with any of these presently, I am transfusing PRBCs only right now (and only O Pos or O Neg, at that).

Originally posted by Quailman:

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Are there no issues with antigens in the plasma and platelets when the components are separated? Is the process 100%, i.e. are there no RBCs in the donated fluid when they take my platelets?

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Honestly, I can't remember. It has been a while since I had to deal with platelets, and even the times I did were few and far between. I would look up the answer for you, but I don't have any research material here, this is all off the top of my head. sorry.

OK, if there are no more questions, lets move on:

So, now it should be clear, as Courk pointed out) who is the Universal Donor (O Neg) and who is the Universal Recipient (AB Pos) and why. Now, I will explain the signifgance of the Pos/Neg compatibility.

Most people will not be affected by a Pos/Neg incompatible transfusion. At the very worst, upon a second (as this will be the quicker secondary response) transfusion of Pos blood to a Neg recipient, a normal, healthy person will experience a slight febrile (feverish) reaction and it is usually nothing to worry about. It becomes an issue, however, during a few instances. If the person is bleeding, and needs every RBC their body can get its hands on, well that is an issue. Also, if they are NOT healthy (sickle-cell anemia patients especially) it can be dangerous. Sickle-cell Anemia is a genetic disorder that destroys RBCs constantly. Sickle-cell patients are usually getting blood transfusions often, and this slight febrile transfusion reaction could actually kill them, because it will destroy RBCs which they are already in short supply of.

It also becomes an issue during pregnancy, and this is where Rhogam comes in.

It is a rare occurence, but it happens: A woman who is Rh Neg becomes pregnant with a baby who is Rh Pos.... twice. This is pretty rare when you consider that (a) only about 15% of the population is Rh Neg, (b) the baby needs to have a Rh Pos father and the genes that create blood type have to mix appropriately to cause an Rh Pos baby (about 50%) and this has to happen twice.

The mother's blood would become what we call 'sensitized' to the D antigen by the blood of the fetus, therefore beginning creation of Anti-D. The Anti-D would cross the placenta into the baby's bloodstream, killing off the baby's RBCs. The first time, this will not kill a baby, because the primary response is too slow and weak to hurt the baby too much. But the second time the Mom's blood encounters the D antigen of a Rh Positive baby, it will kill the baby. This is called HDN for Hemolytic Disease of the Newborn (hemolysis is a reference to the breaking apart of blood cells). Until Rhogam.

The Anti-D from the Mom is a 'specific' antibody, and specific antibodies are IgG. Non-specific antibodies are IgM. IgG antibodies, being the smallest, can fit through the tiny holes in the placenta to cross into the baby's blood. IgM antibodies are too large. What Rhogam is is a manufactured antibody that is IgM and also Anti-D. It is a D-specific antibody that breaks the rules by being IgM and therefore, too big to cross the placenta. When Mom's body senses the Anti-D in her bloodstream, it ceases to manufacture Anti-D in its IgG form.

Rh-Negative mothers and mothers-to-be are always given a shot of Rhogam before and after all of their pregnancies to assure that their bodies will not produce any IgG Anti-D.

Questions?

[AcidFast]

BTW, was this interesting? I am thinking about giving this class to a group of medical professionals next week. I would like your input.

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"She looked up at him with that strange helplessness with which people on the ground regard people on roofs."

[Quailman]

I find it very interesting, but I am not a medical professional. Shouldn't they know this stuff already?

[Courk]

I find it very interesting, and I plan on being a medical professional, but, at 17, I'm obviously not.

I think it'd make a good class. The only issue I had was the fact I needed to read everything twice to sort it out. Then again, this is all new to me - the people you teach might have some background. One thing that helped me, though, was when I went through the little chart with blood types and their antigens and said, "OK, if A is given to B, then this happens. If it's given to AB then this happens. If it's given to O, this happens." I learn best through pictures, so the little mental image I made up to go with that helped me. I can't really describe it, but if you could somehow make a picture illustrating that and draw it on a chalk board, it might be beneficial.

What's the next class on?

[Mercuria]

hmm... i have no idea where i learned it, but i knew the antigen part...

and was told that the pregnancy thing was if the baby had a different blood type at all...

funny how things get contorted when you learn them from regular people...

[Samadhi]

The solution for HDN is quite ingenious.

[AcidFast]

Originally posted by Quailman:

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Shouldn't they know this stuff already?

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Not necessarily. Doctors go through a basic laboratory science course, but it is not very thorough, and not something that they would probably remember all of. Most non-lab techs are not usually trained in this stuff, they usually would be familiar with the compatibility issues, but not the reasoning behind it.

Originally posted by Mercuria:

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funny how things get contorted when you learn them from regular people...

---

Indeed. I once got into an argument with a generator mechanic on which blood type is the universal donor. She was convinced that I probably forgot, and her memory was more reliable than my training. Its not uncommon for people to mistake one of the most prevalent blood types (O Pos) with the universal donor (O Neg) as was the case with her (of course, we understand why she was wrong, don't we, class?). I got really upset, and yelled at her, "This is not something that we learn in school, get tested on, and forget! If I don't know this stuff like the back of my hand, people can die!" Maybe a tad on the melodramatic side, but I feel it was justified

Also, we give Rhogam to any Rh-negative mom, because there is no way to tell what the baby's blood type is going to be.

Courk, of course, IRL I am planning to use visual aids for my class. It was actually an interesting challenge to attempt it here, without them.

For a sidebar, I can explain to you the way we test for blood types. Its simple, really. We have little bottles of antibody that are manufactured, as well as little bottles of RBCs suspended in saline. They are commercially prepared. We take some of a patient's blood, and do what we call 'washing' the cells. We put in a clean test tube one drop of blood, and then fill it with saline. We spin the whole thing in a centrifuge, which clumps the cells down at the bottom of the tube. We pour off the liquid on top, then repeat the process a few times. Then we add saline to make a (approximate) 2%-3% suspension of RBCs in saline. The suspension is mixed with Anti-A, Anti-B, and Anti-D, while the plasma is mixed with the commercially prepared A and B cell suspensions. We spin it down in the centrifuge, so it clumps up at the bottom, then gently shake the tubes, re-suspending the RBCs in the saline. the reactions range from a clump that does not break apart at all (4+), which happens with the A and/or B grouping, to the RBCs completely resuspending, turning the mixture back to the Kool-Aid it looked like before we spun it (=). The D grouping will often have a slightly less positive reaction (3+ or 2+) than the A and/or B grouping. In the blood bank, in order to guard against errors in transcription, we use slightly different symbols. The '=' is use to indicate a negative reaction, and we never use '-' or '+' when referring to blood types, it is always written out 'Pos' or 'Neg'.

So, with five tubes, we will get a series of reactions that looks something like this:

code:

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Blood Type                 Patient Cells with:                   Patient plasma with:


                      Anti-A      Anti-B     Anti-D              A cells     B cells


                  


A pos                   4+          =          3+                   =           4+





B Pos                   =           4+         3+                   4+          =





AB Pos                  4+          4+         3+                   =           =





O Pos                   =           =          3+                   4+          4+





A Neg                   4+          =          =                    =           4+





B Neg                   =           4+         =                    4+          =





AB Neg                  4+          4+         =                    =           =





O Neg                   =           =          =                    4+          4+

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So, the clumping together of the cells in the test tube is an indication of what would happen in the blood stream. You also may have heard the term 'type and cross'. The representation above is the type part, and the cross refers to 'crossmatch'. This is simply a final check where we mix the patients plasma with the cells of the unit, and hopefully get a negative reaction. This is a 'compatible' crossmatch.

whew! My hour is up, I am getting kicked off the computer now.

AF

[winterHLepsilon]

It is interesting, these stuff.

[Quailman]

I gave platelets this morning. They screwed up and only did a single when I was supposed to do a split (double). I like to do the split platelet donation because I am hooked up to the machine twice as long and get to see more of the movie. This morning I chose We Were Soldiers.

[Antrax]

You get movies? Damn. All we get are biscuits and a crappy juice box
Antrax

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"Look, that's why there's rules, understand? So that you think before you break 'em" - Lu-Tze, Thief of Time

[Quailman]

If you donate whole blood you're in and out of the chair (cot? recliner?) in 15 - 20 minutes. For platelets, the phlebotamist inserts a needle in one arm, designated the 'return', and gets the saline solution hooked up and draws off a whole blood sample for testing. Then she inserts a needle in the other arm and this one draws the blood out. It then goes through some sort of contraption that I do not pretend to understand, and extracts the platelets. Then the plasma and RBC's are returned through the return arm, along with some of the saline solution. To get one pint of platelets requires that 6 or 7 (I think) pints of blood be processed. You're hooked up to the machine, unable to move either arm for 45-50 minutes. That's why you get movies, and I must say that I am impressed with the playlist at the blood center. Afterwards I still get the juice and cookies.

Plasma works similarly, except obviously the contraption is a bit different to extract a different component. Both Plasma and Platelet donation can be done one-armed, so you have one free. The machine takes a cup or so of blood, processes it, and then returns it to the same arm (through the same needle). This takes quite a bit longer.

I said I prefer to do double platelet donations. It's partly because of the effort involved in gettting there and getting set up, but mostly because, for example, the bullets were just beginning to fly in the movie when I was finished this morning.

[Courk]

[Nauplius]

I've given platelets several times and never once did we get a movie. You lucky bastard. We had to watch some stupid soap opera, or CSPAN or some such crap.

[Quailman]

Where I donate, they really want us to come back. There are three platelet machines (I'm sure Acid Fast could tell us what they're called) on one side of the room, with a television with DVD/VCP mounted on the ceiling in front of each. They'll ask you after the movie starts if the headphone volume is okay.

And if your feet start to cramp, they bring you a little cup with a few tums in it and pour them into your mouth. I think they'd massage my feet if I asked.

[Courk]

How do tums help your feet?

[Quailman]

I don't understand the physiology behind it, but I think it's a way to get calcium into your system rather quickly.

[Courk]

We get to learn this soon in my anatomy class. Since I already know it, I can slack off that day.

Thanks, AF!

[One Skunk Todd]

What happens if you're a vampire and you feast off the living of the wrong blood type?

[Courk]

Well, today was the day we learned this. AF, I have questions for you.

My professor said that a first-time Rh neg mother with an Rh pos baby won't have any reaction because the blood has to actually be exposed first, and that the only time this will happen is during child birth since the placenta separates mom's blood from baby's blood. She didn't mention anything about primary responses. Can you clarify that? Is it somehow the combination of the two or anything?

She also said that Rhogam just inhibited the production of the anti-Rh antibodies. To me that implies that the Rhogam affects the immune system's ability to make antibodies, but from what I understood from your posts, the Rhogam makes the body think it has the antibodies, and will indeed function as an antibody, but it's just too large to cross the placenta and thus won't harm the baby.

[AcidFast]

I am checking into this...

[austinap]

[Courk]

I think what AF was saying is that people who have sickle-cell anemia have inefficient red blood cells, and since those blood cells keep bursting apart and the bone marrow can't produce enough to keep up with demand, they need blood transfusions to provide a good supply of oxygen and stuff. Should the transfusion not match in terms of positive and negative (like, the patient has neg blood and is given pos blood), the patient's body will react and produce antibodies that will kill the new blood cells it is receiving. Not good when those blood cells are really needed.

[austinap]

You're right, I was just clarifying that point.

[AcidFast]

Well, I haven't gotten clarification on this yet, but it sounds to me like you are correct about the blood thing. The more I think about it, it seems that a primary response, even though longer than the secondary, would not take 9 months or more. Also, if an IgM antibody is too big to pass through the placenta, then an RBC definitely would not be able to. They are much, much bigger than antibodies.

[austinap]

[confused pregnant woman]

This has been the best discussion I've found on the topic. I've donated blood several times in the past and did the blood typing in HS bio class - blood type result all of the times was A+. I am now pregnant and when they did the blood typing it came back A -. Nobody could explain how this could happen. I'm trying to do some research on my own- 1st any idea how this could happen and 2nd what happens if I an A+ woman gets a Rhogam shot because the doctors believe she is A-? I've already refused one shot when I had some spotting. Any thoughts on this?

[AcidFast]

There are a few ways that I can think of that your blood type came back different. However, the Rhogam shot is not harmful to you, and I must recommend that you take it in any case. If we lacked the means to test your blood type, you would be given it regardless, it is better to be safe than sorry.

[AcidFast]

As far as the discrepancy in the results:

There could be a few reasons why your results are different. Clerical errors, although uncommon, are possible. Also, there is sometimes a mixed reaction with a weakly positive D reaction. This can sometimes be interpreted incorrectly. The thing is, that assuming you are D-negative is always the safer of the two. If you are on record as being D-negative, you will always get D-negative blood, and will get a Rhogam shot regardless. This is certainly the safer of the two, because to get positive blood or no Rhogam shot will open up the possibility of you creating the anti-D antibody (if you are negative), and this can cause complications such as HDN, discussed above in this thread.

To give you a better analysis of your discrepancy in results, I would have to actually see them myself, unfortunately.

AF

[antlantic pearl]

"A and B blood types have a strange quality: The body makes antibodies to the opposite bllod type automatically."

This is not a strange quality; it is simply because the A andB antigens are ubiquitously expressed on a lot of bacteria that new-borns are exposed, thus antibodies to these antigens are made early in life if the baby does have A and B antigens on their RBCs surface.

[NeocortX]

WAEA? All this Blood-grouping talk reminds me of Junior High human biology class.

[The Ragin' South Asian]

what blood type do vampires find most delicious?

[Courk]

***Warning: Might contain "Lost" spoiler if you haven't seen Episode 20 - Do No Harm***

So I was watching Lost, and one of the characters needed blood. He knew he was A neg, so the doctor sent someone to ask everyone else what their blood type was. Few knew their type, and of those that did, no one was A neg. So the doctor said, "OK, I guess we'll have to use mine, I'm O neg." I was thinking, "Perfect! Why didn't you say anything earlier?" But then he continued, saying that his blood wasn't a perfect match and that the character might go into anaphylactic shock.

So, did the writers make that up for dramatic effect, or is that true? I can't think of a reason why he'd go into shock, but I'm not an expert.

[extropalopakettle]

I'm not an expert either, but I think there are other "factors" besides the A/B/AB/O and Rh+/Rh- factors. But given it was on TV ("reality" TV?), I'd say it was for dramatic effect.

[Courk]

Not reality. Scripted. I don't watch "real life," I live it.

[Haley*]

Hey everyone, okay so one day i was riding in a car and a few buddy's of mine were dicussing the Rhogam shot. I personally believe that it is harmful to many women carrying their second child. NOT ALL.. but many. For Instance, My mother had the shot and then had her second child, My brother,who has severe autism. Also,my Foster mother has a Severe rett child which she believed was due to the rhogam shot. Of the research that i have done, i would recommend that you do not get the shot, when this shot wasnt around, how did the people deal with it? There are healthy babys born without the shot. Back in the 50's, this shot wasnt around, there were still healthy babys born. i would recommend that you do not get this shot. If you do, get Mercury Free. Babys have not developed Bile and cannot get rid of it, so given that all the mercury that is delivered to them , that may be the reason why they turn out the way they do. Please consider my Veiw on this subject.
If you have any questions or extra information, please email me, i am still researching on this and i would love to hear anything anyone has to say.
xo_angelofyours_ox@yahoo.com