Quick answer
What Is Transcutaneous Oxygen Pressure?
Transcutaneous oxygen pressure (TcPO2) is a needle-free test that measures how much oxygen reaches the skin, using a small heated sensor. The results help your doctor assess whether a foot wound is likely to heal, how severe the lack of blood flow is, and a safe amputation level if amputation cannot be avoided.
Sources01 / Understanding the procedure
About Transcutaneous Oxygen Pressure
What Is Transcutaneous Oxygen Pressure
A wound needs enough oxygen to heal. Oxygen is carried by the blood to the small blood vessels in the skin, and some of it passes through the skin. Transcutaneous oxygen pressure, or TcPO2, measures the oxygen that comes out through the skin. The better the blood flow to the skin, the higher the value.
How It Works at a Glance
A small sensor is attached to the skin with an adhesive ring and a drop of contact fluid. The sensor is warmed to about 44 degrees Celsius so the small vessels widen and oxygen passes through the skin more easily. After about 10 to 20 minutes, the oxygen value stabilizes and is recorded in mmHg.
Reading the Results
- About 40 mmHg or more: skin oxygen is usually sufficient for wound healing.
- 30 to 40 mmHg: borderline, so the result is interpreted together with other tests.
- Below 30 mmHg: skin oxygen is very low, often indicating severe limb ischemia and the need for a procedure to restore blood flow.
These numbers are general guidance. Results are affected by swelling, infection, thick skin, temperature, and the condition of the heart and lungs, so your doctor interprets them together with your overall condition.
TcPO2 and Other Tests
TcPO2 is often done together with skin perfusion pressure (SPP), the ABI test, or toe pressure. Sometimes the measurement is repeated while you breathe oxygen or while the position of your leg is changed, to see how much the skin can improve. If the results are low, your doctor may follow up with a duplex ultrasound or angiography.
02 / Understanding the procedure
When Is This Procedure Considered?
A doctor may consider this procedure in the situations below. The decision is always made after a thorough assessment.
- Slow-Healing Foot WoundsTo assess whether there is enough oxygen in the skin around the wound for healing.
- Foot Wounds in People with DiabetesHelps assess blood flow to the skin when stiff arteries make the ABI test less reliable.
- Suspected Severe Limb IschemiaFor example, foot pain at rest, pale or bluish skin, or blackened tissue.
- Determining the Amputation LevelIf amputation cannot be avoided, TcPO2 helps estimate the level that is likely to heal well.
- Assessing the Results of a Procedure or TherapyAfter a balloon, stent, bypass surgery, or oxygen therapy, to see whether skin oxygen has improved.
Situations to Consider First
- Open Wound Directly at the Sensor SiteThe sensor is placed on intact skin near the wound, not over the wound.
- Severe Leg SwellingFluid in the tissues keeps oxygen from passing through the skin, so the value may appear lower.
- Skin Infection or InflammationInflammation changes how the skin uses oxygen. Your doctor decides the right time for the test.
- Very Thick Skin or CallusesThick skin blocks oxygen, so the sensor is moved to thinner skin.
- Sudden Pale, Cold, and Painful FootThis can signal a sudden blockage. Do not wait for a scheduled test, and go to the emergency room right away.
03 / Before the procedure
How Should You Prepare?
The TcPO2 test requires no special preparation and no fasting.
Smoking. Avoid smoking for a few hours before the test, because smoking reduces the oxygen that reaches the skin.
Skin. Do not apply lotion or cream to your legs and feet on the day of the test. Some hair at the sensor sites may be shaved so the sensors stick firmly.
Keep your feet warm. Arrive early and rest in the room for about 15 minutes before the test.
Clothing. Wear loose clothing that rolls up easily. A reference sensor is usually also placed on the chest below the collarbone.
Medications. Take your regular medications as usual. Tell the staff if you use oxygen at home or have lung disease.
Unsure about the preparation instructions? Ask our team before the procedure.
04 / During the procedure
How Is the Procedure Done?
The test usually takes about 45 minutes, because each sensor needs time to stabilize. It takes longer if many sites are measured or additional oxygen tests are done.
Rest and Position
You lie on your back in a warm room and rest so your blood flow stabilizes.
Attaching the Sensors
The skin is cleaned, then small sensors are attached with an adhesive ring and a drop of contact fluid at several sites, such as the top of the foot, near the wound, or the calf. One reference sensor is placed on the chest.
Warming and Waiting
The sensors are warmed so your skin feels warm. The oxygen value is left to stabilize for several minutes. You need to stay still and breathe normally.
Additional Tests If Needed
Your doctor may request repeat measurements while you breathe oxygen through a mask or while your leg is raised or lowered.
Finishing and Results
The sensors are removed and the skin is cleaned. TcPO2 values are available right away and are explained together with other test results by your treating doctor.
05 / Benefits and risks
Benefits and Risks Should Be Discussed Together.
Every medical procedure has benefits and risks. Your doctor will explain both for your situation before the procedure.
Benefits You Can Expect
- No Needles and No RadiationIt only uses sensors attached to the skin, so it is safe to repeat.
- Assesses the Chance of Wound HealingIt helps estimate whether a foot wound can heal with the oxygen that reaches the skin.
- Helps Choose the Amputation LevelIf amputation is needed, it helps determine the level that is likely to heal well.
- A Basis for Treatment DecisionsIt helps your doctor decide whether a balloon, stent, or bypass surgery is needed to save the leg.
- Monitors Treatment ResultsChanges in TcPO2 values show whether skin oxygen improves after a procedure or therapy.
The benefits of a procedure are not a promise of a cure. Ask how the results will affect your care plan.
Risks You Should Know
- Skin Redness at the Sensor SitesCaused by the warmed sensor. It usually fades within a few hours.
- Small Blisters on Fragile SkinRare, especially on very thin skin. The staff monitor the skin and can move the sensor.
- Results Affected by Many FactorsSwelling, infection, thick skin, cold temperatures, or lung disease can make the value lower than it really is.
- Does Not Show Where the Blockage IsTcPO2 assesses oxygen in the skin, not the location of artery narrowing, so a duplex ultrasound or angiography may be needed.
- Mild Irritation from the AdhesiveThe adhesive ring can make the skin red or itchy for a short time.
Risks can differ from person to person. A full explanation and consent are given after an individual assessment.
06 / After the procedure
What Is Recovery Like?
There is no recovery period. You can return to your activities right away.
Skin. The sensor sites may show round red marks for a few hours, which fade on their own.
Wound dressings. Dressings are reapplied according to the nurse's instructions.
Discussing the results. Your doctor explains whether skin oxygen is sufficient for wound healing, or whether a procedure is needed to restore blood flow.
Foot care. Check your feet every day, keep them clean and dry, stop smoking, and control your blood sugar if you have diabetes.
Warning signs. Go to the emergency room right away or contact the medical team if you have:
- A foot that suddenly becomes very painful, pale, cold, or numb
- A wound that worsens, turns black, smells, or oozes pus
- Spreading redness and swelling, with fever
- A blister or new wound at a sensor site
Know the Signs That Need Prompt Care.
Follow the team's guidance on warning signs. If severe or sudden symptoms appear after the procedure, go to the nearest emergency department right away or call Heart Attack Center 1500 258.
07 / Team and support
Doctors and Procedure Support
The doctors below are listed for this procedure. Listed by name, not by ranking.
dr. Debby C. Soemitha, Sp.PD
Internal Medicine
Clinical focusDiabetes and Diabetes Complications · Obesity and Metabolic Disease
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dr. Emanoel Oepangat, Sp.JP(K)
Interventional Cardiology
Vascular Diagnostic and Therapeutic Center +1 center
Clinical focusCoronary Intervention · Peripheral Vascular Intervention
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dr. Suko Adiarto, Sp.JP(K), Ph.D.
Interventional Cardiology
Vascular Diagnostic and Therapeutic Center +1 center
Clinical focusCoronary Intervention · Peripheral Vascular Intervention
View Profile08 / Common questions
Before You Plan the Procedure.
Frequently asked questions about transcutaneous oxygen pressure testing. Your doctor will explain what the results mean for your situation.
Is the TcPO2 test painful?
No. There are no needles or injections. You only feel the warm sensors attached to your skin during the test. After the sensors are removed, the skin may show round red marks for a few hours. Tell the staff if the warmth feels too hot or uncomfortable.
Why does the test take quite a long time?
The sensors need to be warmed and left for several minutes until the oxygen value stabilizes. If several sites are measured, or your doctor requests additional tests with oxygen breathing or changes in leg position, the test takes longer. For this reason, set aside about one hour, including preparation and rest before the test.
What does my TcPO2 value mean?
As general guidance, a value of about 40 mmHg or more indicates skin oxygen that is usually sufficient for wound healing. A value below 30 mmHg indicates very low oxygen and often requires a procedure to restore blood flow. Your doctor interprets this number together with the condition of the wound and other tests.
What is the difference between TcPO2 and skin perfusion pressure?
Both assess blood flow in the skin. Skin perfusion pressure measures the pressure at which blood starts flowing again, using a cuff and a laser sensor. TcPO2 measures the amount of oxygen that reaches the skin, using a heated sensor. Your doctor may use one or both to assess the chance of wound healing.
Why is there a sensor on my chest?
The chest sensor serves as a reference. The oxygen value in the leg is compared with the value on the chest, so your doctor can tell whether a low leg value is caused by poor blood flow to the leg or by a genuinely low oxygen level throughout the body.
What happens if my TcPO2 result is low?
A low value suggests that the wound may be hard to heal without improving blood flow. Your doctor usually follows up with a duplex ultrasound or angiography to look for artery narrowing, then discusses procedures such as a balloon, stent, or bypass surgery. Wound care and blood sugar control continue at the same time.
Sources and Medical Review
Translated from the Indonesian edition medically reviewed by dr. Emanoel Oepangat, Sp.JP(K).
Sources as cited in the Indonesian edition.
- Fitridge R, Chuter V, Mills J, et al. The intersocietal IWGDF, ESVS, SVS guidelines on peripheral artery disease in people with diabetes and a foot ulcer. Diabetes Metab Res Rev. 2024;40(3):e3686.
- Conte MS, Bradbury AW, Kolh P, et al. Global vascular guidelines on the management of chronic limb-threatening ischemia. J Vasc Surg. 2019;69(6S):3S-125S.e40.
- Arsenault KA, Al-Otaibi A, Devereaux PJ, et al. The Use of Transcutaneous Oximetry to Predict Healing Complications of Lower Limb Amputations: A Systematic Review and Meta-analysis. Eur J Vasc Endovasc Surg. 2012;43(3):329-336.
- Catella J, Long A, Mazzolai L. What Is Currently the Role of TcPO2 in the Choice of the Amputation Level of Lower Limbs? A Comprehensive Review. J Clin Med. 2021;10(7):1413.
- Mazzolai L, Teixido-Tura G, Lanzi S, et al. 2024 ESC Guidelines for the management of peripheral arterial and aortic diseases. Eur Heart J. 2024;45(36):3538-3700.