This answer was provided by colleague Justin Hanenberg, MS MLS: “D-dimer is considered to be a nonspecific biomarker, and elevated levels can be seen during infection, inflammation, cancer, trauma, or pregnancy. Our baseline D-dimer levels also increase as we age, leading many in the medical community toward an age-adjusted cut-off for people aged 50 years and older. For example, someone 70 years old would have an age-adjusted cut-off at 700 ng/mL FEUs (Age x 10 ng/mL FEUs). Like the CT scan, the D-dimer is also used as a rule-out test, where positive results aren’t conclusive but negative results are. If you are concerned with the level of D-dimer beyond age or general inflammation, follow up with your care provider about additional workup to an underlying cause. One last note: be mindful of measuring units when reading D-dimer results. Laboratories may use different units or expressions like “DDU” or “FEU” that are not the same but can be converted. In the U.S., “ng/mL FEUs” is the most common reporting unit for D-dimer.”
Thanks for this response from (soon to be Dr.) Hanenberg, who is a Rutgers University DCLS resident. In 2020 and 2021, the D-dimer was employed to predict COVID-19 patient progress. This resulted in a surge in D-dimer testing, creating concern for elevated results among apparently healthy people. In response to over 40 inquiries, I (Geo) prepared an essay attached to my June 19, 2021 Fritsma Factor entry, “Isolated Chronically Elevated D-dimer.” For a recent discussion, please follow this link to a December 26, 2025 article, ” August 2025 CAP Today: D-dimer Reporting and INR are Variables that Matter.” We welcome your comments.
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