Feedback Friday: All about blood typing

Dear Ask An Eggspert – I had some bloodwork done at my initial testing. I don’t know what certain things mean.  Can you tell me what I should be looking at with these tests? Antibody Screen, RBC w/Refl ID, Titer and Ag, Titer and Typing?–Layman in Los Angeles

Dear Layman–Thanks for reaching out.  Let’s see if we can offer some insight as far as these tests go. For the cliff notes version, you can skip to the bottom. 

The tests you have listed relate to your individual blood type..  

• Antigens are markers on you red blood cells (RBC) to tell us what blood type you have. 
  • You may have heard of “ABO” blood types. You are either A-blood, B-blood, AB-blood or O-blood.  
    • A blood has A antigens attached to the surface of the RBC membrane. 
    • B blood has B antigens attached to the surface of the RBC membrane. 
    • AB blood has both A and B antigens attached to the surface of the RBC membrane. 
    • O blood has no antigens attached to the surface of the RBC membrane. 
  • There is another type of antigen called “Rh Factor.” 
    • If you have Rh factor, you are Rh positive.
    • If you do not have Rh factor, you are Rh negative. 
  • But wait, there is more!!! There are minor antigens similar to Rh that you either have, or you don’t. These are minor because it is uncommon for someone to have these minor antigens. These aren’t always tested for to identify your blood type, but they will be if your antibody screen is positive. 
• Now, we have to talk about antibodies. Similar to disease inoculation and immunizations, your red blood cells are programed to recognize other blood cells as being similar or different.  
  • If similar, the blood cells flow past one another without reaction. 
  •  If recognized as being different, your blood cells will trigger a reaction to destroy this alien cell. 
  • The proteins triggered to fight the alien cell are called antibodies. 
  • If you have ever been exposed to different blood types, with different antigens, your body will create antibodies to fight off any new cells with foreign antigens. 
  • A titer tells us how much antibody you have to a particular antigen. 

When considering pregnancy or fertility treatments, there are a few reasons we need this information.  Let’s start with the most CRITICAL, and work our way through the others: 

• Blood loss and resuscitation should there be a complication during or after surgery.  
  • Though low, any time you have surgery, your surgeon will want to make sure your blood type has been verified, charted, and that resources (or alternative options) to replenish a large volume loss have been located.  This is true whether you are having surgery in a hospital or in a stand-alone surgery center.  
• Now, the next thing you could be thinking is, “well, I’m just getting started in my fertility treatment journey and how do you know I am going to need surgery, and therefore why do you need my blood type?  The answer to relates to pregnancy.  
  • For pregnancy purposes, the the Rh factor and minor antigens are important.
  • If you and your partner are different, particularly if you have Rh (or minor antigen) negative blood and your partner has Rh (or minor antigen) positive blood, your baby may have Rh (or minor antigen) positive blood. 
  • During a delivery (or miscarriage), you will be exposed to some amount of your baby’s blood cells. Your body with then create antibodies to those antigens. 
  • Fast forward, some time has passed, you and your partner become pregnant again.  If your next baby has the same Rh or minor antigens, your body will attack your baby’s RBCs because your body has been programmed to look out for and destroy cells with those antigens. 
    • As your baby is growing, and the number of RBCs increases, your body may fight it off and cause serious complications for the developing baby, and immediately after delivery. 
      • Most often, your first pregnancy won’t be an issue because you won’t already have antibodies. 
      • Your obstetrician wants to know your blood type so that they can treat you with medication during your pregnancy, and delivery, to prevent you from developing an immune response to your growing baby, or your next baby. 
      • Your obstetrician also needs to know if you have antibodies and if you need to be watched more closely during your pregnancy. 
    • Your fertility doctor wants to know if you are at risk for a few reasons.
      • If you are Rh negative and have a miscarriage, we want to treat you with medication to prevent you from developing an immune response to your next pregnancy.
      • With any subsequent pregnancies, your fertility doctor wants to know your risk to help you prepare for any special treatment you may need in your pregnancy. 

Wheh, that was a lot of science!!!
So, for those tests:

1. Antibody screen is testing to see IF you have made any antibodies to antigens that are not on your own RBCs. 
2. RBC w/Refl ID–This is a REFLEX test to IDentify which antigens you have made antibodies to. Some antibodies are more important than others. 
3. Titer and Ag–This is a test to tell us, not only which antigens (Ag) you have made antibodies (Ab) to, but also how many antibodies you have made. The higher the number, the more likely your body is to react and rapidly destroy cells that have the Antigen. 
4. Titer and Typing–This is the same as above, just some different words … it is identifying the type of antibody you have and how many antibodies you have made. 

Cliff Notes Version: your MD needs to know if you are Rh- so that if you experience bleeding during pregnancy, or miscarriage, he/she can treat you within 72 hours of this exposure.  

Your lab tests are ordered to tell your MD: 

• If you have A, B, AB or O blood. (ANTIGENS) 
• If you have Rh +/- blood, (ANTIGENS)
• If you have any ANTIBODIES (a previous exposure) to any dissimilar blood.  
• REFLEX tests are run if/when any result returns with a positive result so that the lab can identify what specifically caused the positive.  Not only do we need to know IF something is there, but we need to know WHAT specifically is there. 
• Titer is how much antibody has been made.

To understand why your doctor may have ordered so many tests at your first visit, check out our post about testing here: https://askaneggspert.com/what-are-all-these-tests/

We hope we met your Eggspectations—An Eggspert

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Disclaimer: All of the comments on this page are for basic information only. They are based on the opinions and expertise of the authors and are not meant to provide a substitute for medical care or specific treatment recommendations. Each person is unique and requires individualized diagnosis and treatment plans. Any specific questions should be directed to your personal healthcare provider.