Registered Nurses' Association of Ontario

Diagnostic Tests to Determine Vascular Supply

Diagnostic Test


Arterial Duplex Scan

  • Non-invasive ultrasound test that can identify macro- and microvascular changes in the arterial tree.
  • Used to diagnose aneurysm and large vessel stenosis >50%.
  • Patients with suspected superficial artery stenosis and claudication may undergo duplex scanning to identify a lesion that is amenable to angioplasty, before subjected to angiogram.
  • Non-invasive arterial duplex scan as having sensitivity and specificity rates greater than 90%.

Continuous Wave Doppler

  • Old technology. It is highly recommended to use in conjunction with duplex imaging to visualize the arteries.


  • Records the “pulse volume recording” – another old tool that can establish diagnosis with limited accuracy.
  • May be a initial diagnostic tool for persons with diabetes that do not have compressible arteries but should be used in conjuction with duplex scan.

Transcutaneous Oxygen (TcpO2)


  • Measures absolute oxygen partial pressure in the dermis. According to Goldman and Salcido (2002), TcpO2 less than 20 mmHg gives a guarded prognosis for healing.
  • 40 mmHg is a good indication for healing.
  • TcpO2 should be measured on upper leg and dorsum of the foot for best results.
  • Areas of callus, edema or bony prominences produce inaccurate results.
  • Valuable for evaluating perfusion and is a good predictor of amputation in the lower limbs.
  • TcpO2 < 30 mmHg was an independent predictor of diabetic foot ulceration.


Toe and Ankle Pressures

  • Systolic toe and ankle pressures are measured with a fitted occluding cuff placed most often around the base of the first toe and around both ankles.
  • Toe pressure of > 45 mmHg is necessary for optimal healing
  • Most patients with  toe blood pressures > 30mmHg healed with  conservative management
  • With ankle pressures < 80mmHg, most patients had an amputation or died before healing occurred
  • Kalani et al. (1999) suggests a cut-off of 25mmHg for TcpO2and 30mmHg
  • for toe blood pressure as predictors of wound  healing, with  TcpO2being
  • the better  predictor in patients with  diabetes and chronic foot  ulcers. Toe pressures, however, may be more technically and economically feasible.
  • Toe pressures for persons with diabetes were more reliable than persons with false negative ABPI’s and lower limb neuropathy
Chronic Disease
Assessment and Management of Foot Ulcers for People with Diabetes - Second Edition
Point of Care Resources