Medical oxygen requires a prescription from a doctor or qualified practitioner, and you get it through a durable medical equipment (DME) supplier rather than a pharmacy or retail store. Your doctor writes the prescription after confirming your blood oxygen levels fall below specific thresholds, and the supplier delivers the equipment to your home, sets it up, and handles ongoing refills or maintenance.
You Need a Prescription First
Medical oxygen is a regulated product. You cannot legally purchase it over the counter for therapeutic use. A physician or other qualified practitioner must order it based on a clinical test showing your oxygen levels are low enough to warrant treatment. The standard threshold for coverage is an oxygen saturation at or below 88% at rest, or a partial pressure of oxygen at or below 55 mm Hg on an arterial blood gas test. Your doctor may also qualify you if your saturation is 89% but you have additional complications like congestive heart failure or pulmonary hypertension.
The prescription specifies your flow rate in liters per minute, how many hours per day you need oxygen, and whether you need it at rest, during activity, during sleep, or all three. This information determines what type of equipment your supplier provides.
DME Suppliers Are the Main Source
Durable medical equipment suppliers are the primary channel for home oxygen. These are companies that specialize in medical devices and respiratory equipment. Some are national chains, others are local or regional businesses. Once your doctor sends a prescription, the DME supplier handles everything: delivering the equipment to your home, training you on how to use it, and scheduling refills if you’re using tanks.
If you have Medicare, make sure both your doctor and the DME supplier are enrolled in the program before you receive any equipment. Using a non-enrolled supplier means Medicare won’t cover the cost. The same principle applies to private insurance. Call your plan first to confirm which suppliers are in-network. Most insurance plans, including Medicare Part B, cover oxygen equipment as a rental rather than a purchase, typically over a 36-month period. After that rental period ends, if you use tanks or cylinders that require physical delivery of oxygen contents, Medicare continues paying for those monthly deliveries for up to five years. You pay 20% of the approved amount for these deliveries.
Three Types of Equipment
The equipment you receive depends on your oxygen needs and lifestyle. All three types deliver the same oxygen, but they work differently and come from different supply chains.
Stationary Home Concentrators
These are the workhorses of home oxygen therapy. A stationary concentrator plugs into a wall outlet, pulls in room air (which is about 21% oxygen), and filters it through a material called zeolite that separates oxygen from nitrogen. What comes out is 90% to 95% pure oxygen in a continuous stream. These units run 24/7, never need refilling, and cost nothing beyond electricity to operate once you have one. They’re too large and heavy to carry around, so they stay in one spot in your home.
Compressed Gas Cylinders
Traditional oxygen tanks store gaseous oxygen compressed to around 2,200 PSI. You attach a regulator to the top that lets you dial in the exact flow rate your doctor prescribed. Tanks deliver a continuous flow of oxygen, meaning it streams out steadily whether you’re breathing in or out. The tradeoff is that tanks hold a finite supply and need regular refills or replacements. Your DME supplier schedules recurring deliveries.
Portable Oxygen Concentrators
Portable concentrators work the same way as stationary ones, filtering and concentrating room air, but they’re small enough to carry in a shoulder bag and run on rechargeable batteries. To achieve that size, most portable units use pulse dose delivery instead of continuous flow. A sensor detects the moment you begin inhaling and releases a small burst of concentrated oxygen timed to that breath. This feels different from the steady stream of a tank or stationary concentrator, but the oxygen itself is identical. Pulse dose won’t work for everyone, particularly people who need high flow rates or who breathe through their mouths during sleep.
What About Buying Online?
In recent years, non-FDA-approved oxygen devices have appeared on Amazon and other retail sites, sold without requiring a prescription. The Pulmonary Fibrosis Foundation and the FDA both warn against purchasing these products. The devices may not deliver the concentration or flow rate needed to treat a medical condition, and using one without clinical guidance means nobody is monitoring whether your oxygen levels are actually improving. Stick with FDA-approved devices prescribed by your doctor and supplied through a legitimate DME company.
That said, some online medical supply retailers do sell FDA-approved concentrators. Reputable ones will ask for a copy of your prescription before shipping. If a site lets you buy an oxygen delivery device without any prescription verification, that’s a red flag.
Hospital vs. Home Oxygen
If you’ve received oxygen in a hospital and wonder whether home oxygen will feel the same, the short answer is that the oxygen itself is identical. Hospital systems often use higher flow settings and deliver oxygen continuously through wall-mounted systems in a quiet, controlled environment. That combination can make hospital oxygen feel “stronger.” Home concentrators produce oxygen-enriched air in the low-to-mid 90% purity range, which matches what hospitals use for non-emergency care. The real difference is in delivery method and setting, not the oxygen molecule itself.
For acute respiratory emergencies, you go to the emergency room. Home oxygen is designed for ongoing, stable conditions like COPD, pulmonary fibrosis, or chronic hypoxemia. It is not a substitute for emergency care.
Traveling With Medical Oxygen
Compressed gas tanks and liquid oxygen containers are not allowed on commercial flights. Portable oxygen concentrators are the only option for air travel. The FAA maintains a list of approved devices, and airlines require you to carry a POC that meets their specific criteria. Earlier rules required a physician’s statement for each flight, but the FAA has since eliminated that redundant paperwork requirement. You still need to notify your airline in advance, and your POC’s battery must last long enough to cover the flight duration plus a buffer, typically 150% of the expected travel time. Check with your airline for their exact policy, as requirements vary.
For road trips, any type of oxygen equipment works, though portable concentrators are the most convenient since they don’t run out. If you’re traveling with tanks, your DME supplier can sometimes coordinate with a supplier at your destination to arrange refills or loaner equipment.
Steps to Get Started
- See your doctor. You’ll need a pulse oximetry reading or arterial blood gas test to document your oxygen levels. If your saturation is at or below 88% at rest, or drops significantly during sleep or activity, you qualify.
- Get a prescription. Your doctor specifies flow rate, hours of use per day, and the medical diagnosis justifying the need.
- Contact your insurance. Confirm coverage details, find in-network DME suppliers, and understand your copay or coinsurance amount.
- Choose a DME supplier. The supplier processes the prescription, handles insurance paperwork, delivers the equipment, and trains you on its use.
- Schedule follow-ups. Medicare and most insurers require periodic recertification, often after 90 days initially, to confirm you still need oxygen therapy.
Initial coverage for some conditions may be limited to 90 days or the length specified in your doctor’s prescription, whichever is shorter. After that period, your doctor re-evaluates and can extend the prescription if the need continues.