HERDOO2 Rule

VTE Recurrence (HERDOO2): Validated rule to identify low-risk women. Men with unprovoked VTE are inherently high-risk and are not eligible for rule-out.

1. Biological Sex

2. HERDOO2 Points (1 pt each)

Recurrence Risk Result

Low Risk

Management Insight

Consider Stopping Anticoagulation

Recurrence rate < 2% per year. Safe to discontinue therapy.

Guidelines & Evidence

Verified

Last Review: 2026-07-17

When to Use

Identifying women with a first unprovoked Venous Thromboembolism (VTE) who have a low risk of recurrence.

Deciding whether anticoagulation can be safely discontinued after the initial 3-6 month treatment period.

The 'Males Always High' Rule

The HERDOO2 rule is only applicable to women. Men with unprovoked VTE are considered high-risk for recurrence (regardless of these points) and usually require indefinite anticoagulation.

How it Works

Point Allocation (1 pt each)

Post-thrombotic signs: Hyperpigmentation, Edema, or Redness in either leg.

Renal insufficiency: Creatinine Clearance < 50 mL/min.

D-dimer: ≥ 250 µg/L (drawn while on anticoagulation).

Obesity: BMI ≥ 30 kg/m².

Older age: Age ≥ 65 years.

Risk Stratification (Women Only)

Score	Risk Class	Recurrence Rate
0 - 1	Low Risk	~1.6% per year (Safe to stop)
≥ 2	High Risk	> 8% per year (Continue VKA/DOAC)

Last Comprehensive Review: 2026-07-17

Recent Journal Updates

WHO NewsJul 20, 2026

Road deaths fall by 21% globally but stronger action is needed to save lives

Clinical Context

We think this might be relevant to the clinical guidance for Herdoo 2 Rule.

WHO NewsJul 2, 2026

WHO adds first diagnostic test for Ebola Bundibugyo virus to its Emergency Use Listing

Clinical Context

We think this has broad domain relevance to Herdoo 2 Rule.

WHO NewsJun 15, 2026

Open letter to leaders of G7, G20, BRICS and all nations on finalizing the WHO Pandemic Agreement’s Pathogen Access and Benefit Sharing annex

Clinical Context

We think this might be relevant to the clinical guidance for Herdoo 2 Rule.

HERDOO2 Rule

Low Risk

When to Use

When to Use

The 'Males Always High' Rule

How it Works

Point Allocation (1 pt each)

Risk Stratification (Women Only)

Clinical Pearls

Unprovoked Pivot

The Evidence

Primary Strategy

Identifying unprovoked venous thromboembolism patients at low risk for recurrence who can discontinue anticoagulant therapy.

Validating the HERDOO2 rule to guide discontinuation of anticoagulation.

Origins & History

Acronym

Recent Journal Updates

HERDOO2 Rule

Low Risk

When to Use

When to Use

The 'Males Always High' Rule

How it Works

Point Allocation (1 pt each)

Risk Stratification (Women Only)

Clinical Pearls

Unprovoked Pivot

The Evidence

Primary Strategy

Identifying unprovoked venous thromboembolism patients at low risk for recurrence who can discontinue anticoagulant therapy.

Validating the HERDOO2 rule to guide discontinuation of anticoagulation.

Origins & History

Acronym

Recent Journal Updates