A concentrator with a documented oxygen-concentration range can be an appropriate source for prescribed home oxygen. A figure such as 93% does not, by itself, mean that treatment is inadequate. Suitability depends on the complete system: its rated performance, prescribed flow and interface, and the person’s clinical assessment.
It is also too broad to say that concentrator and cylinder oxygen are always interchangeable. Follow the source and settings recommended by the treating team, including the backup arrangement.
Keep three different numbers separate
Source concentration is the percentage of oxygen in the gas leaving the device. Continuous flow, measured in litres per minute, is the volume of gas supplied. Blood oxygen saturation, estimated as SpO₂ by a pulse oximeter, is a measurement from the person.
These describe different things. A concentrator showing 93% does not mean the patient’s blood saturation is 93%. A good blood-saturation reading does not certify the machine’s output. And a higher flow does not automatically make an unsuitable or faulty device safe.
Understand the specification
Many concentrators use pressure swing adsorption to remove much of the nitrogen from room air. The resulting gas still contains other gases, including argon and residual nitrogen. Read the manufacturer’s stated oxygen range rather than expecting 100% from every concentrator.
For a model specified at 93% ±3%, the stated range is 90–96%. Check the flow range and conditions to which that claim applies. If the unit is outside its declared performance at a rated setting, ask the supplier to assess it. Do not accept an unexplained low value as an inevitable consequence of using the top of the rated range.
Why the clinical assessment still matters
With a nasal cannula, source oxygen mixes with additional room air during breathing. The flow, breathing pattern and interface affect what reaches the lungs. This is why comparing only the purity printed on two sources does not establish an equivalent treatment.
The treating team assesses whether the chosen setup meets the person’s needs. Do not change flow to compensate for a purity concern, or switch to a different delivery mode without an agreed plan. Equipment intended for a specialised circuit may have different requirements from routine cannula use.
Respond to a possible output problem
Learn what the machine’s indicators actually report. Some provide a warning when concentration crosses a threshold; not all display a continuously measured percentage. A supplier may need appropriate test equipment to assess output. A fingertip oximeter cannot perform that test.
For an alarm or suspected fault, use the prescribed backup plan and contact the supplier. For new or worsening symptoms, follow the clinical action plan; urgent symptoms need medical help without waiting for a purity test.
Keep the source specification and service history with the prescription. The useful question is whether the exact equipment is performing as documented and meeting the individual care plan.