D-Dimer (DDI) Lab Values

Hey everyone. It’s Abby from nursing.com. In this lesson, we’ll discover what causes an increased or decreased value in the D-Dimer. We’ll also talk about its normal value. Let’s dive in.

D-Dimer is a lab value that is abbreviated as DDI. It measures the amount of D-Dimer in a blood sample. D-Dimer is a byproduct that’s produced as part of fibrinolysis or the breakdown of clots. We’re going to see a significant elevation in D-Dimer in clotting disorders or conditions and in this case, disseminated, intravascular coagulation, what are there a ton of, blood clots right? Now, our body naturally sends in substances to break down clots when one forms and that byproduct is D-Dimer and when we measure it, we can tell how much clotting is happening because of the amount of D-Dimer that’s being produced as a byproduct. A clinical indication for this, spoiler alert, from the last slide is DIC. Can you see all that clotting, all those fibers and everything, all that part of the clotting cascade. Now, it’s used to identify and monitor DIC, but also to rule out a blood clot. So, if someone comes in with signs and symptoms of PE like shortness of breath or that sense of impending doom, this lab can be measured to see whether or not D-Dimer is being produced and if there’s a clot there at all. It’s also going to be indicated to rule out a blood clot for DVT so, there could be that unilateral pain in the extremity, right. Um, which would then create a PE.It’s also going to be evaluated in the case of stroke. Uh, mostly an ischemic stroke, of course, because that’s when a blood clot gets lodged in the vessels. 

Normal values are below or equal to 250 nanograms per milliliter. This lab is collected in a light blue lab tube. You’ve probably seen this with COAG studies. Lab values are going to be increased in these conditions or during these times: surgery, trauma, infection, cancer, doesn’t this all sound a bit inflammatory, right? Heart attack, pregnancy, we talked about DVTs and DIC. What happens in surgery?  Incisions… What do incisions do? They bleed and they eventually clot. So, of course, it’s going to increase in these times, right? These are all times the blood clots, my little ridiculous drawing here, uh, when a blood clot forms, the body’s gonna try to break it down and release the D-Dimer. Now, lab values will be decreased when there’s a lack of D-Dimer. So, that could be a lack of blood clot breakdown or a lack of blood clots. 

Our linchpins for this lesson or that the D-Dimer or the DDI lab is measured to quantify the substance. That is DDI, that is released as blood clots disintegrate. A normal value is less than or equal to 250 nanograms per milliliter. We’ll see an increase in this value in the presence of blood clots, because the body is trying to take care of them. We see blood clots in ischemic strokes, in the case of a pulmonary embolism, and of course, DIC and DVT. A decreased value will be when there’s a lack of clot breakdown. So, this could be a disease, a disorder, or just a lack of blood clots in general. 

Now, you all did great on this lesson. I hope that increases your understanding. Remember, we’ve got your back and we want you to go out, be your best self today, and happy nursing.

References:

• https://ltd.aruplab.com/Tests/Pub/0030057
• https://healthy.kaiserpermanente.org/health-wellness/health-encyclopedia/he.d-dimer-test.abn2838#:~:text=A%20low%20or%20normal%20d,is%20a%20blood%2Dclotting%20problem
• https://nursing.com/dashboard/