Transfusions are common in the medical world. In fact, blood transfusion has been cited as one of the five most overutilized therapeutic procedures in the United States. There are times when it seems that a transfusion is ordered without a complete assessment of the clinical picture. For example, communications with various Blood Bank techs reveal that a physician will frequently transfuse a patient when the hemoglobin has dropped below 8.0 g/dL. (A low hemoglobin count is generally defined as less than 13.5 g/dL for men, 12.0 g/dL for women, but this threshold may differ slightly depending on the hospital.) However, a low hemoglobin in the absence of active bleeding may not be sufficient cause for transfusion. In any case, millions of patients are transfused annually, sometimes with multiple units over extended periods of time. A cancer patient, depending on the type of cancer, may end up being transfused 1-2 units … Keep reading!
The ABO system is the first system considered when it comes to transfusions. A Type O individual can only receive Type O blood, while a Type AB individual can receive A, B, AB, and O. This system was first described by Karl Landsteiner in 1900, which was a landmark achievement in the world of blood banking. The ABO antigens are found on red cells and platelets, as well as many circulating proteins and even various tissues in the body (which comes into play for organ transplantation). Failure to properly match ABO types for blood transfusions can result in acute intravascular hemolysis, renal failure, and death; in organ transplants, it is possible to see acute humoral rejection of the transplanted organ. As such, ABO testing is of critical importance in any pretransfusion scenario and is of high importance before transplantation. Apart from the rare Bombay phenotype, all red blood cells express the … Keep reading!
In today’s post, I want to get into Blood Bank testing, which is my favorite part of working in a clinical lab. In my time working for the Mayo Clinic in Rochester, MN, this is the type of work that I did on a daily basis. Now that I work in a smaller hospital with a very low volume of transfusions, the scope of work I perform in Blood Bank is significantly reduced. If I were to leave my current job, returning to this type of work is something I would highly prefer. That being said, let’s get into some of the specifics. Perhaps you recall earlier in this series a brief discussion of antigens. As I said, antigens are surface markers on the red cell membrane made up of sugars or proteins. The specific combination of antigens a person expresses is called an antigen profile. An individual’s genetic structure … Keep reading!
Congratulations! You’ve donated a unit of whole blood. But what happens with it now? Well, I’m going to tell you, you lucky dog. Most, if not all, donor centers will remove a very large portion of the white blood cells present in the unit. The bag setup used in the collection has a filter present in the tubing below the initial collection bag. There is a connector in the tubing that has to be opened, and the blood will then drain out of the original bag, pass through the filter, and fill a second bag. The WBCs are removed because they can cause different reactions through the transfusion process. One criteria of these filters is that they must allow for the retention of at least 80% of the RBCs and reduce the WBC content to less than 5×10^6. Then the blood is centrifuged (which means it is spun down at high … Keep reading!
Someone is heading to the operating room to have open-heart surgery. Someone else is coming into the ER, banged up and bleeding profusely from a car accident. And someone else is chronically low on blood because of cancer. They all need to be transfused, but where do we get the blood they need to have? Probably the most well-known national source of blood for transfusions is the Red Cross. I’m sure you’ve seen signs at work, school, or elsewhere advertising blood drives performed by the Red Cross or some other more local blood collection facility. It’s a great way to provide a needed service to those in medical need. Eligible donors take between 30 and 60 minutes to get signed in, have their hemoglobin level checked, donate their unit, and recover with juice/pop and some cookies or other food item(s). I think most people have the biggest fear about the … Keep reading!
In my last post, I told you about the components of blood. ::Jedi hand-wave:: You found that fascinating. ::Wave done:: Good, now that we have that established, let’s move on to more facts about blood. This time, I want to tell you a little bit about blood groups. Attached to various components of red blood cell membranes are surface markers called antigens. Antigens are made up of sugars or proteins. Everyone has these antigens in various combinations, which sometimes makes for difficult circumstances when trying to match blood for transfusions (more on that in a later post). These antigens can be classified into four divisions: Systems, Collections, Low-Frequency Antigens, and High-Frequency Antigens. I want to focus on the ABO and Rh systems for the purpose of this discussion. Fun fact before we move on: The International Society of Blood Transfusion (ISBT) has accepted a total of 274 antigens (Jeffrey McCullough, Transfusion Medicine 2nd Edition, … Keep reading!
Blood. This fluid found in all of our bodies is useful for more than senselessly coating the set of a horror film. Blood transports oxygen and nutrients to the cells in our body via red blood cells, carries cellular waste products away for disposal, contains white blood cells that are used to combat infection, and is the medium in which platelets and clotting factors travel throughout our system. It is a vitally important element of our physical make-up. But have you ever stopped to consider the complexity inherent in blood? For many of you, I would guess a lot of what I’m going to tell you will be new information. I hope you enjoy this look [dramatic pause] at blood. Because of the nature of what I do, there is a lot that I can say on this topic. As such, this will have to be broken down into multiple … Keep reading!