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Age-Adjusted D-Dimer Assay Threshold

For adults older than 50 evaluated for pulmonary embolism with low or intermediate clinical probability, use a validated highly sensitive assay and its reported FEU or DDU convention.

Formula & worked example
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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Health results are educational estimates, not a diagnosis or treatment recommendation. A qualified clinician can interpret measurements in the context of your health.

Formula and method

Age 70 gives 700 µg/L FEU or 350 µg/L DDU, with the assay type explicitly selected.

For age above 50: threshold (µg/L) = age × 10 for FEU assays or age × 5 for DDU assays.

Worked example

Enter these known values and leave the other values blank.

Age (years): 70 years
Assay reporting convention: FEU

Age multiplier: 10000 µg/L
Age-adjusted assay threshold: 0.7 µg/mL

Assumptions and limitations

For adults older than 50 evaluated for pulmonary embolism with low or intermediate clinical probability, use a validated highly sensitive assay and its reported FEU or DDU convention. This outputs a threshold, not a measured D-dimer value or a diagnosis. It is not intended for high clinical probability or anticoagulated patients.
Clear an unknown control before solving the supported arithmetic relationship.
This model does not select medical treatment or establish a diagnosis.

Common questions

How is the result calculated?

For age above 50: threshold (µg/L) = age × 10 for FEU assays or age × 5 for DDU assays.

When does this model apply?

For adults older than 50 evaluated for pulmonary embolism with low or intermediate clinical probability, use a validated highly sensitive assay and its reported FEU or DDU convention. This outputs a threshold, not a measured D-dimer value or a diagnosis. It is not intended for high clinical probability or anticoagulated patients.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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