1. Can this test be done in a doctor's office?
Blood gas measurements are usually done in a hospital since the analysis should be done immediately after the blood has been collected and requires specialized equipment. Most GPs do not have such equipment in their surgeries.
2. I've had pneumonia before and currently have asthma. Why has my doctor never requested this test on me?
Most cases of pneumonia or asthma can be diagnosed by symptoms and monitored by listening to your chest sounds or by examining the results of spirometry tests or chest x-rays. Most of the time, asthma will respond to your usual medications and pneumonia to rest and possibly antibiotics. Blood gas tests may be necessary if you have severe, sudden or long-term breathing problems. In these cases, blood gas tests are usually done in a hospital setting.
3. Is there any other way to measure my oxygen levels?
A pulse oximeter is a noninvasive way (no needle to obtain a blood sample is required) of continuously monitoring oxygen saturation. A small clip-like device (called a sensor) is attached to the end of the finger or earlobe. The sensor reads light that is transmitted through the skin. Pulse oximeters are useful for monitoring oxygen saturation, but their accuracy can be affected by the presence of abnormal forms of haemoglobin, like carboxyhemoglobin (present in carbon monoxide poisoning), low pulse rate due to poor circulation, and very low levels of haemoglobin due to severe anaemia.
