How to Choose Compression Stocking Size
Measure the leg circumference at the ankle (narrowest point above the malleolus), calf (widest point), and below the knee, then match these measurements to the manufacturer's specific sizing chart for the brand you're prescribing, recognizing that proper fitting is critical since most ready-made stockings don't fit the majority of venous disease patients.
Measurement Technique
The evidence reveals a significant problem: ready-made compression stockings fit poorly in most patients with venous disease. When legs were measured at seven anatomical points, only 4.7-7% of patients fit properly into standard ready-made stockings 1. This means you must be meticulous about sizing.
Key Measurement Points
Measure circumference at these locations with the patient standing or leg dependent:
- Ankle (B point): Narrowest circumference just above the malleolus
- Calf (C point): Widest circumference of the calf
- Below knee (D point): Just below the knee
Critical Fitting Considerations
Each manufacturer has different sizing standards - there is no universal sizing system 1. You must:
- Use the specific sizing chart for the brand you're prescribing
- Consider that different brands fit different percentages of patients (one study showed 53.5% fit for one brand vs 0% for another) 1
- Recognize that measuring at only three points (standard practice) may overestimate proper fit compared to seven-point measurement 1
Pressure Selection Based on Disease Severity
Once you have measurements, select compression class based on clinical severity 2:
For mild to moderate disease (C2-C4):
- 20-30 mm Hg compression is the minimum recommended pressure 2
For severe disease (C5-C6 with ulcers):
- 30-40 mm Hg compression is advised 2
- For ankle-brachial index 0.6-0.9: reduce to 20-30 mm Hg 2
- Contraindication: Do not use compression if ankle-brachial index <0.6 (indicates arterial disease requiring revascularization) 2
Important Caveats
The Oversizing Problem
Interestingly, wearing an oversized class III stocking can provide similar or higher pressures than a properly-sized class II stocking 3. This means if a stocking feels too tight, simply going up one size in the same compression class may not reduce pressure as expected.
Proper Fitting is Essential for Adherence
Adherence should be encouraged with proper fitting, education, and detailed instructions 2. Poor fit is a major cause of non-compliance, which historically was blamed on patient behavior but is actually often due to improper stocking selection 2.
Consider Custom Stockings
Given that the majority of patients don't fit ready-made stockings 1, consider custom-fitted stockings for patients who:
- Have unusual leg anatomy
- Report discomfort with ready-made options
- Have poor adherence despite education
Verify Actual Applied Pressure
If available, use a pressure monitor to verify the actual compression being delivered, as applied pressures vary significantly based on the device and who applies it 4.