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What this equipment is
E0601 is the HCPCS code for a continuous positive airway pressure (CPAP) device — the primary first-line therapy for obstructive sleep apnea (OSA). The device delivers pressurized air through a mask to keep the airway open during sleep.
CPAP is classified as rented DME under Medicare Part B. The rental cap is 13 months of continuous use, after which the patient owns the equipment and Medicare covers supplies only.
Medicare coverage criteria
- Polysomnography (Sleep Study). Apnea-Hypopnea Index (AHI) or Respiratory Disturbance Index (RDI) ≥5 events/hour in a patient with symptoms; or AHI/RDI ≥15 regardless of symptoms.
- Symptoms. Daytime sleepiness, impaired cognition, mood disorders, insomnia, or documented hypertension. Documentation must show at least one symptom.
- Physician order. A qualifying face-to-face encounter with the treating physician, documenting the diagnosis and medical necessity for CPAP.
- CMN (Certificate of Medical Necessity). For Medicare, a completed CMN with the sleep study results, physician notes, and estimated length of need.
What actually causes denials in DME back offices
- Missing or incomplete sleep study. The sleep study (PSG or home sleep test) must meet technical standards — AHI/RDI calculated by a qualified physician, interpreted and signed off. An unsigned or unread study kills the claim.
- CMN not attached or unsigned. E0601 claims submitted without a CMN or with an unsigned CMN will be denied. The CMN is the primary medical necessity document.
- No qualifying diagnosis code. The ICD-10 code must match the sleep study findings. G47.33 (obstructive sleep apnea) is the most common — make sure it aligns with the severity documented in the study.
- Prior authorization not obtained. Many commercial payers require PA for CPAP. Billing without an active PA number is a near-guaranteed denial.
- Therapeutic trial failure not documented. Some payers (including some Medicare Advantage plans) require proof of CPAP adherence (≥4 hours/night, ≥70% of nights) before continuing coverage past the initial period.
- Wrong modifier. KX modifier required when all LCD criteria are met. Missing KX = denial under many payer rules.
Documentation checklist
- Signed physician order with date and diagnosis
- Polysomnography report with AHI/RDI values and interpretation
- CMN completed and signed by treating physician
- Documentation of at least one qualifying symptom
- Proof of delivery signed by patient or caregiver
- PA number (if required by payer)
Reimbursement note: Medicare's allowed amount for E0601 varies by region. The rental rate applies for up to 13 months of continuous use, after which ownership transfers to the patient. Supplies (A7030, A7031, etc.) are billed separately throughout the rental period and after cap completion. Commercial payer rates vary by contract — verify against your fee schedule before setting patient expectations.
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Frequently asked questions
Does Medicare cover CPAP for mild sleep apnea (AHI 5–14)?
Yes, but only with documented symptoms. If AHI is 5–14 with no daytime sleepiness, impaired cognition, insomnia, or hypertension, Medicare may deny for insufficient medical necessity. Document all qualifying symptoms in the physician notes.
What happens after the 13-month CPAP rental cap?
The patient owns the device. Medicare continues to cover medically necessary supplies (masks, cushions, tubing, filters) at the scheduled frequency limits. The equipment itself is no longer billable for rental — only supply claims continue.
How do I prove CPAP adherence for continued coverage?
Most payers require CPAP download data showing ≥4 hours/night on ≥70% of nights over a consecutive 30-day period within the first 90 days. Your DMS (data management system) should generate an adherence report — attach it to your CMN recertification or PA request.