Home oxygen therapy (HOC) provides supplemental oxygen to individuals who cannot get enough from breathing air alone. Most insurers classify this therapy as Durable Medical Equipment (DME), intended for long-term use in the home. Qualification requires meeting strict clinical criteria and completing specific administrative steps. Understanding the medical necessity and required documentation is the first step toward accessing this care.
Establishing Medical Necessity for Home Oxygen
Qualifying for home oxygen requires demonstrating chronic hypoxemia, or low blood oxygen levels, through specific diagnostic testing. Physicians typically require an arterial blood gas (ABG) test or a pulse oximetry test to measure oxygen saturation (SpO2) while the patient breathes room air. These tests must be performed while the patient is in a “chronic stable state,” meaning they are not experiencing a temporary illness or acute event that would artificially lower oxygen levels.
Qualification for stationary oxygen is met if the SpO2 is measured at 88% or lower while the patient is at rest. A saturation of 89% may also qualify if the patient has a secondary diagnosis, such as chronic cor pulmonale, pulmonary hypertension, or erythrocytosis. These secondary conditions indicate that low oxygen levels are causing complications in other body systems.
The need for oxygen may also be established during specific activities or sleep. If a patient’s SpO2 level falls to 88% or below for at least five cumulative minutes during a minimum two-hour sleep study, they may qualify for nocturnal oxygen use. Qualification for portable oxygen is possible if the SpO2 drops to 88% or less during exercise, provided the level improves when oxygen is administered.
Medical records must confirm that alternative treatments, such as inhalers or other medications, have been considered and deemed insufficient to address the hypoxemia. The prescribing physician must document that the patient has a severe lung disease, such as Chronic Obstructive Pulmonary Disease (COPD), or other hypoxia-related symptoms expected to improve with supplemental oxygen. A mandatory face-to-face visit with the treating physician must take place within 30 days before the initial certification date.
Required Physician Documentation and Certification
Once medical necessity is established, the physician must fulfill specific administrative requirements to authorize the therapy. The primary documentation is the Certificate of Medical Necessity (CMN), which consolidates the clinical justification for the equipment. This document formally outlines the medical need and confirms that the patient meets the required oxygen saturation criteria.
The CMN must contain precise details regarding the prescribed oxygen regimen. This includes the exact flow rate measured in liters per minute (LPM), the specified duration of use (continuous, non-continuous, or nocturnal), and the method of administration (nasal cannula or mask). The physician’s signature on this form certifies that the ordered items are medically necessary.
Oxygen prescriptions are not indefinite and require periodic re-evaluation to confirm continuing medical need. For many payers, including Medicare, documentation of a qualifying blood gas study or oxygen saturation test is required prior to the 13th month of therapy. The physician must re-evaluate the patient and complete a recertification process to ensure the therapy remains appropriate.
Navigating Insurance and Coverage Requirements
Home oxygen equipment is covered under the Durable Medical Equipment (DME) benefit of insurance plans like Medicare Part B, which has specific coverage rules. The patient must obtain the equipment from a DME supplier enrolled with Medicare that accepts assignment. After the yearly Part B deductible is met, the patient is responsible for a 20% coinsurance of the Medicare-approved amount.
Medicare’s coverage for home oxygen operates on a 5-year cycle, beginning with a 36-month mandatory rental period. During these first three years, the monthly rental fee covers the equipment, maintenance, and supplies, including the oxygen contents. The supplier retains ownership of the equipment throughout this cycle.
After the initial 36 months, monthly rental payments cease. However, the DME supplier must continue providing the equipment, supplies, and maintenance for an additional 24 months, provided the patient still has a medical need. If the patient uses tanks or cylinders, they continue to pay the 20% coinsurance for the periodic delivery of the oxygen contents. Patients with private insurance often require prior authorization from the insurer before delivery, involving a similar review of medical necessity documentation.
Receiving and Maintaining Home Oxygen Equipment
After qualification and authorization, the DME supplier coordinates the delivery and setup of the prescribed equipment. The supplier provides training on the proper operation of the equipment, which typically includes a stationary oxygen concentrator, compressed gas cylinders, or a liquid oxygen system. Concentrators filter oxygen from the air for stationary use, while tanks or liquid systems offer portability.
A major focus of the setup is ensuring the safe use of oxygen, as it supports combustion and increases fire intensity. Oxygen equipment must be kept at least 5 to 10 feet away from open flames, heat sources, or electrical appliances that could spark. Smoking is prohibited near the equipment. Flammable materials, such as oil-based creams, petroleum jelly, or grease, should never be used on the face or near the oxygen supply.
The supplier provides instructions for routine maintenance, such as regularly cleaning the oxygen concentrator’s filters with warm, soapy water. Compressed gas cylinders and liquid oxygen vessels must be stored upright in a secured position in a well-ventilated area to prevent tipping. Adhering to the supplier’s instructions and safety guidelines ensures the equipment remains functional and mitigates fire hazards.