age_adjusted_d_dimer: Age-Adjusted D-dimer for VTE

In cliot: Clinical Indices and Outcomes Tools

Age-Adjusted D-dimer for VTE

Description

Applies an age-adjusted cutoff to D-dimer interpretation for the exclusion of Venous Thromboembolism (VTE), including Pulmonary Embolism (PE) and Deep Vein Thrombosis (DVT). In patients > 50 years old, the cutoff is adjusted to (Age * 10) ng/mL, increasing specificity without compromising sensitivity.

Usage

age_adjusted_d_dimer(age, d_dimer, d_dimer_units = "ng/mL")

Arguments

age	Numeric. Patient age in years.
d_dimer	Numeric. The measured D-dimer level.
d_dimer_units	String. Units of the D-dimer measurement. "ng/mL" (default) - uses a base cutoff of 500. "ug/mL" or "mg/L" - input is converted to ng/mL (multiplied by 1000) before comparison.

Value

A list containing:

Age_Adjusted_Cutoff_ng_mL	The calculated threshold for this patient.
Patient_D_dimer_ng_mL	The patient's D-dimer standardized to ng/mL.
Result	"Negative" (Rule out) or "Positive" (Further testing needed).
Interpretation	Clinical guidance based on the result.

References

Righini M, Van Es J, Den Exter PL, et al. Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study. JAMA. 2014;311(11):1117-1124. doi:10.1001/jama.2014.2135

Examples

# Example 1: 65-year-old with D-dimer 600 ng/mL
# Standard cutoff (500) would be positive.
# Age-adjusted cutoff (65 * 10 = 650) is higher.
# Result: Negative (600 < 650) -> PE Ruled Out.
age_adjusted_d_dimer(65, 600)

# Example 2: 40-year-old with D-dimer 600 ng/mL
# Age <= 50, so cutoff remains 500.
# Result: Positive (600 > 500).
age_adjusted_d_dimer(40, 600)

# Example 3: 70-year-old with D-dimer 0.8 ug/mL
# Converts to 800 ng/mL. Cutoff is 700.
# Result: Positive (800 > 700).
age_adjusted_d_dimer(70, 0.8, "ug/mL")

cliot documentation built on Dec. 1, 2025, 1:06 a.m.