Age-Adjusted D-Dimer Calculator

Your details

Patient age in years. The age-adjusted formula applies when age is above 50. Below 50 the standard 500 ng/mL FEU cutoff is used.
years
Choose the unit that matches your laboratory report. FEU (fibrinogen equivalent units) cutoff is twice the DDU cutoff for equivalent results.
The D-dimer result from the laboratory in the unit chosen above. Leave blank to see only the threshold without a result comparison.
ng/mL
Age-adjusted cutoffPE excluded
650

Threshold in the chosen unit: if patient result is at or below this, PE can be excluded in low/intermediate pre-test probability

Cutoff in ng/mL FEU650ng/mL FEU
Result interpretationNegative - PE can be excluded (low/intermediate pre-test probability)
Margin from cutoff-50
650
Standard range<500Age-adjusted zone500-1000Elevated1000+

D-dimer is below the age-adjusted cutoff - PE exclusion supported.

  • At age 65, the age-adjusted cutoff is 650 ng/mL FEU (65 x 10), versus the standard 500 ng/mL FEU fixed threshold.
  • The measured D-dimer is 50 ng/mL FEU below the cutoff, supporting PE exclusion without imaging in a low or intermediate pre-test probability patient.
  • This rule-out applies only when clinical pre-test probability is low or intermediate (e.g., Wells score below 5). High pre-test probability patients should proceed directly to imaging.

Next stepConfirm that pre-test probability is low or intermediate before using this result to exclude PE. Document clinical probability (e.g., Wells criteria) in the chart.

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