Oxygen is a drug and therefore requires prescribing in all but emergency situations. In the emergency situation oxygen prescription is not required.
Before oxygen therapy is prescribed there are guidelines or criteria that must be met. These criteria involve a blood test. (These blood test criteria must also be met for Medicare and other insurers to pay for the oxygen costs.) Medical experts produced the criteria. They establish what the levels of oxygen in the blood must be for oxygen therapy to be needed.
These guidelines describe three conditions that require the use of oxygen therapy:
1. PaO2 is less than or equal to 55 mmHg. Or hemoglobin oxygen saturation (SaO2) measured by pulse oximeter is less than or equal to 88 percent when breathing room air at rest.
2. PaO2 of 56-59 mmHg. Or if the hemoglobin oxygen saturation (SaO2) is equal to or greater than 89 percent when linked to specific conditions. These may include Cor Pulmonale, congestive heart failure or erythrocytosis. (With a hematocrit of greater than 56 percent.) (Erythrocytosis means there are more red cells in the blood than normal. Hematocrit measures the percentage of cells in a sample of blood.)
3. Some individuals do not qualify for oxygen therapy while at rest. But they may require oxygen while walking, exercising or during sleep. Oxygen therapy is needed in these cases when the hemoglobin oxygen saturation (SaO2) falls to less than or equal to 88 percent. Also, for the costs of oxygen to be covered by insurance there must be proof that the oxygen therapy used during exercise or sleep improves the individual's hypoxemia.
A physician must write a prescription for oxygen therapy prior to delivery. The prescription will indicate the flow rate, how much oxygen you need per minute -- referred to as liters per minute (LPM) -- and when you need to use oxygen.
Also necessary is Diagnosis, portability (if needed), and length of need. Some people use oxygen therapy only while sleeping, others only while exercising, and still others need oxygen continuously.
Your physician will order a blood test or oximetry test that will indicate what your oxygen level is and help determine what your needs are. A written prescription is required prior to delivery.
Certain insurance polices may pay for all your oxygen, but payment is based on laboratory results, diagnosis, and other information. The information listed below will help you to determine insurance coverage.
Medicare – In addition to a prescription, Medicare requires a Certificate of Medical Necessity (CMN) to be filled out by your physician. CMN Oxygen requirements are as follows:
1. Length of need.
2. Diagnosis, a respiratory ailment showing the need for oxygen.
3. Oxygen Blood Gas to be 56-59 or below, or Oxygen Saturation level to be 89 or below.
4. How the test was taken, room air, during exercise, or while sleeping.
5. The testing facility where blood gasses or oximetry was performed.
6. Portability if needed.
7. Liter flow prescribed.
8. Physicians Signature.