My approach to possible transfusion reactions is extremely simple. I use a deliberately overaggressive approach and a low threshold for doing a reaction workup. This is important because of the inherent danger of missing or misdiagnosing an acute hemolytic transfusion reaction, in particular (more on that to follow).
Functionally, this means that any time something unusual happens during transfusion, I take it seriously. In fact, not only do I take it seriously, I actually assume that the patient is having a hemolytic transfusion reaction, and I force myself to disprove it. 999 times out of 1000, I can do so, but that approach ensures that I will (hopefully) never miss one of the most important reactions. Such an approach also ensures that I will evaluate for one of the other reaction types as well.
So the assumption of a significant reaction means that the first thing I do when I am confronted with something unusual during transfusion is to ask a simple question: "Has the transfusion been stopped?" I ask this before I even evaluate any of the clinical signs and symptoms we'll discuss below, because continuing to infuse incompatible blood (we're assuming hemolysis, remember?) is the worst thing you can do for the patient.
You're probably thinking about now that I might be just a little bit nuts. "Does that mean that if a person sneezes or belches or notices an ingrown toenail during transfusion that this guy is going to treat it as acute hemolysis?", you might ask. Let's not be ridiculous! I simply mean that I believe that you must maintain a high, intelligent index of suspicion for acute hemolysis, and if that means you work up numerous negative reactions, so be it! I should tell you that not everyone is as aggressive as I am in their approach to transfusion reactions. That's OK; I'm not claiming that they are wrong and I am right. I simply believe that I would rather work up a thousand negative possible reactions to find the one true case of acute hemolysis than be less aggressive and miss one.
OK, so the first step in the process of evaluating a possible transfusion reaction is established. In my view, it is:
Step One: STOP THE TRANSFUSION!
Next, let's discuss how to recognize suspicious signs and symptoms of reactions clinically.