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Free Age-Adjusted D-dimer Calculator

Calculate the ADJUST-PE age-adjusted D-dimer reference cutoff for patients over 50.

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Last updated October 13, 2026 · Report an error

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Per the ADJUST-PE study (Righini M, et al. "Age-Adjusted D-Dimer Cutoff Levels to Rule Out Pulmonary Embolism", JAMA 2014;311(11):1117-1124), for patients over 50 the age-adjusted D-dimer cutoff is: cutoff (ng/mL FEU) = age x 10. For age 50 and under, the traditional fixed cutoff of 500 ng/mL FEU is used. This tool reports the reference cutoff value only — it does not interpret an actual D-dimer result or assess pulmonary embolism risk. For general reference and educational purposes only — not a medical diagnosis. Consult a doctor for actual D-dimer interpretation, which also depends on the specific assay and pre-test probability.

How it works

Enter the patient's age. The tool applies the ADJUST-PE formula (age x 10) for ages over 50, or reports the traditional fixed 500 ng/mL FEU cutoff for age 50 and under.

  1. Enter age (years).
  2. Click Calculate to see your results.

Examples

Age 60

Cutoff = 60 x 10 = 600 ng/mL FEU, per the ADJUST-PE age-adjusted formula.

Age 45

Cutoff = 500 ng/mL FEU (traditional fixed cutoff, since age is 50 or under).

Who should use it

  • Reviewing D-dimer reference ranges for older patients.
  • Emergency medicine and internal medicine education.

Industry applications

  • Emergency medicine reference
  • Hematology and pulmonology education

Advantages

  • Based on a well-cited, peer-reviewed study (ADJUST-PE, JAMA 2014).
  • Simple, transparent formula.

Limitations

  • Reference cutoff only — does not interpret an actual result or assess PE risk.
  • Assumes FEU units; some labs report D-dimer in different units (DDU), which do not directly apply this cutoff.

Common mistakes to avoid

  • Applying the age-adjusted formula to patients age 50 or under, where the traditional fixed 500 ng/mL FEU cutoff still applies.
  • Treating this cutoff as a diagnosis rather than a reference threshold used alongside clinical probability assessment.

Best practices

  • Always interpret D-dimer results together with pre-test clinical probability (e.g. a validated score) and a doctor's assessment.

Tips

  • This cutoff applies specifically to D-dimer reported in FEU (fibrinogen equivalent units) — confirm your lab's reporting units before comparing.

Frequently asked questions

Yes, with no signup and no limit on how many calculations you run.
No — this tool only computes the age-adjusted reference cutoff value. Interpreting an actual D-dimer result requires a doctor considering the specific assay used, pre-test probability (e.g. Wells score), and clinical context.
D-dimer levels tend to rise naturally with age, which increases false-positive results using the traditional fixed cutoff in older patients. The ADJUST-PE study found that scaling the cutoff to age helped rule out pulmonary embolism more accurately in patients over 50, without missing more cases.

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