Platform
Company
Blood Gases
Review status
Currently under review
Pending specialist review and validation.
Deoxyhemoglobin Arterial measures the proportion of hemoglobin in your arterial blood that is not carrying oxygen. The measurement is made by co-oximetry on an arterial blood gas sample, which separates hemoglobin into its different forms. It complements oxygen saturation and the partial pressure of oxygen to show how effectively your lungs load oxygen onto hemoglobin.
Because it is reported as a fraction of total hemoglobin, this test reflects the balance between oxygenated and deoxygenated hemoglobin at the moment of sampling. It is commonly ordered in emergency, intensive care, and perioperative settings to provide a real-time view of oxygen transport.
This test helps your care team understand whether your arterial blood is adequately oxygenated. A higher proportion of deoxyhemoglobin suggests reduced oxygen loading, which can occur with breathing problems, lung disease, impaired gas exchange, low ventilation, or poor circulation. Clinicians use it to evaluate shortness of breath, respiratory failure, shock, and the response to oxygen therapy or ventilator changes.
It is also useful when abnormal hemoglobin species are suspected. Carboxyhemoglobin from carbon monoxide exposure and methemoglobin from certain drugs or illnesses can reduce effective oxygen carriage. Co-oximetry distinguishes these forms so your team can target the underlying cause and optimize oxygen delivery.
Your result is interpreted together with the rest of your blood gas panel, your symptoms, and examination. If the deoxyhemoglobin fraction is higher than expected, your team may look for causes such as inadequate ventilation, pneumonia, pulmonary embolism, heart failure, or low blood flow, and may adjust oxygen or ventilator settings accordingly.
A lower than expected fraction generally reflects high arterial oxygenation, for example during supplemental oxygen therapy. If the number does not fit the clinical picture, your clinician may repeat the sample, review collection technique, and consider interference from hemoglobin variants or dyshemoglobins. Discuss trends over time and follow your clinician’s guidance on next steps, which might include further respiratory evaluation or treatment adjustments.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Breathing supplemental oxygen lowers the deoxyhemoglobin fraction, while high altitude or low inspired oxygen can increase it. Report any recent oxygen use or changes in your breathing equipment.
Air bubbles, delayed analysis, poor mixing, or using the wrong syringe can alter co-oximetry results. Arterial samples should be collected in heparinized syringes, promptly mixed, and analyzed quickly.
Cigarette smoke and carbon monoxide exposure raise carboxyhemoglobin, which affects oxygen carriage and can change the measured deoxyhemoglobin fraction. Tell your clinician about smoking or possible exposures.
Drugs such as dapsone, nitrates, nitrites, and topical anesthetics can cause methemoglobinemia, interfering with oxygen binding and co-oximetry measurements. Provide a full medication and supplement list.
Low hemoglobin, sickle cell disease, thalassemia, or fetal hemoglobin may influence co-oximeter readings and how results are interpreted. Specialized testing may be needed if variants are suspected.
Poor circulation, sepsis, or low blood pressure can impair oxygen delivery and extraction, leading to changes in deoxyhemoglobin. Clinical context and other blood gas values help clarify the cause.
References