Hi, Abby here with nursing.com. In this lesson, we’ll discuss fibrinogen, and of course we are going to talk about the clotting cascade. We’ll talk about normal values, increased values, decreased values, and why we would draw this lab. Let’s get started! 

A blood test for fibrinogen quantifies the amount of fibrinogen that is in circulation. And what is fibrinogen? It’s a protein that’s synthesized in the liver, and it’s part of the clotting cascade. It’s a precursor to fibrin and what it does is that it aids in blood clot formation. So, it actually binds the platelets together, so that it can start to form a clot, and it supports platelets coming into the site,  that’s called aggregation. And you can see here, that’s evident, that fibrin clot is starting to accumulate, and fibrinogen is what starts that process. 

So, some clinical indications of when we might take this test, are when we’re looking for the etiology of uncontrolled bleeding. Is there a problem in the clotting cascade? Could it be fibrinogen? Now we would see this, or we would want to know which part of the clotting cascade, if something’s missing needs to be replaced, in times of like placenta abruption, that’s when the, uh, placenta comes off the uterine wall and all of those crazy capillary endings on the uterus side don’t clot, and get taken up, and it bleeds like crazy, that it can even go into disseminated intravascular coagulation. Now, abnormal PT or PTT values are also an indication to draw this lab, and in the case of genetic clotting disorders. 

A normal therapeutic value for fibrinogen would be between 150 and 430 milligrams per deciliter. Because we’re taking it as part of coagulation, it’s going to be taken in a light blue heparin tube. Some lab values would be increased when we have chronic DIC, chronic DIC. That’s different from when we have acute DIC, and we’ll talk about the difference over here in a moment. It’s also going to be increased in the face of inflammation, so that could be autoimmune disease, especially rheumatoid, or glomerulonephritis, or during an acute infection, because what wants to come to the rescue when there’s inflammation? That’s actually what calls those platelets to the bleed. Now, it’s also going to be increased in stroke, trauma, it increases with age, and in lifestyle-based inflammation like that of obesity and smoking. It will be decreased, there will be less fibrinogen, in acute DIC because what’s happening? A massive, a massive amount of clotting everywhere, right? And so then, that means that the fibrinogen is taken up because there’s so much clotting that’s happening. It would also be decreased in a deficiency of fibrinogen, or in the case of fibrinolysis. This is the body’s natural, um, fight or natural process of breaking down that clot, and we don’t want fibrinogen in that, in that portion, um, when regular normal, healthy fibrinolysis is happening. It’s also going to be decreased in hemorrhage, why? Because fibrinogen is being taken up. It will be decreased with liver disease, because the liver is what synthesizes these proteins, and in the case of excessive alcohol consumption, we always say alcohol thins the blood, right? It doesn’t actually thin the blood, it just makes it less coagulable, and then also in genetic clotting disorders. 

So, our linchpins for this lesson are that the fibrinogen lab is going to test for how much fibrinogen is in circulation. It’s part of the clotting cascade that builds blood clots. It’s a precursor to fibrin. A normal value is between 150 and 430 milligrams per deciliter. We’ll see, fibrinogen increased in the case of inflammation or chronic DIC. The body is chronically clotting, so there’s going to be more fibrinogen, and also in trauma, that fibrinogen is trying to come to the rescue to create clots, right? It will be decreased in the case of hemorrhage, or liver and kidney disease, or if there’s a deficiency. And then we also see it decreased in acute DIC. You remember why? That’s right, because it’s all taken up. There’s not enough fibrinogen to go around because it’s all taken up in all of those clots. 

Now, this wraps up our lesson on fibrinogen. Hopefully, that helped your understanding. Remember, we love you guys. Now, go out and be your best self today and as always, happy nursing.

References:

• https://ltd.aruplab.com/Tests/Pub/0030130
• https://www.ucsfhealth.org/medical-tests/fibrinogen-blood-test
• https://my.clevelandclinic.org/health/diagnostics/22791-fibrinogen-test
• https://pathologytestsexplained.org.au/learning/test-index/fibrinogen
• https://www.uptodate.com/contents/disorders-of-fibrinogen?search=fibrinogen%20elevated&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1