Pulmonary Function Test Denied by Insurance? How to Appeal

Pulmonary function tests (PFTs) are among the most fundamental diagnostic tools in respiratory medicine — non-invasive, well-validated, and endorsed by every major respiratory society as the standard of care for diagnosing and managing lung disease. When an insurer denies coverage for a PFT, they are essentially arguing that your physician does not need objective data to treat your lungs. That argument is both medically and legally weak. Here is how to push back effectively.

Why Insurers Deny Pulmonary Function Tests

Understanding your insurer's specific denial rationale is the key to reversing it. PFT denials tend to cluster around a handful of recurring justifications.

"Not medically necessary" is the most common denial reason, and the hardest to defend given the clinical record. Spirometry is recommended by the American Thoracic Society (ATS), the European Respiratory Society (ERS), and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as the diagnostic standard for asthma (ICD-10: J45) and COPD (ICD-10: J44). DLCO testing is endorsed by the ATS for evaluating interstitial lung disease (ICD-10: J84), pulmonary fibrosis (ICD-10: J84.10), and pulmonary hypertension (ICD-10: I27.0). If your insurer claims a PFT is not necessary, your physician's appeal should cite which specific guideline they are following.

Duplicate testing denials occur when an insurer has records of a prior PFT and argues that repeat testing is not warranted. This rationale misunderstands how PFTs are used clinically. Serial spirometry is the standard method for monitoring disease progression and assessing treatment response in COPD and asthma — not just a one-time diagnostic tool. The GOLD and GINA guidelines explicitly recommend periodic reassessment. Document the specific clinical reason for repeat testing in your appeal.

CPT coding errors are a major source of preventable PFT denials. The relevant codes are: CPT 94010 (spirometry, basic), CPT 94060 (spirometry with bronchodilator evaluation), CPT 94729 (DLCO), CPT 94726 (plethysmography for total lung capacity), and CPT 94150 (vital capacity). A mismatch between the ordered test, the billed code, and the documented diagnosis can trigger an automatic denial. Always confirm with your pulmonologist's billing department that codes were submitted correctly before assuming the denial is clinical in nature.

Prior Authorization Denied: How to Appeal" class="auto-link">Prior authorization failures arise when the ordering physician or hospital did not obtain authorization before the test, or when the authorization request lacked sufficient clinical documentation. In this case, the clinical justification likely existed — it just was not transmitted to the insurer properly.

Step-therapy requirements occasionally appear in PFT denials, where the insurer argues that a simpler test (such as peak flow measurement) should be attempted before a full PFT panel. This argument is clinically unsound for anything beyond basic asthma monitoring and should be challenged with guideline citations.

How to Appeal a Pulmonary Function Test Denial

Step 1: Identify the Exact Denial Reason

Read your EOB)" class="auto-link">Explanation of Benefits (EOB) and denial letter carefully. Identify the specific CPT code denied, the stated reason, and any guideline or policy the insurer cites. If the letter references a coverage determination or clinical policy, request a copy of that document — you are entitled to it under federal regulations (29 C.F.R. § 2560.503-1 for ERISA plans, ACA regulations for marketplace plans).

Step 2: Verify Billing Codes with Your Provider

Contact your pulmonologist's billing department and confirm that the CPT codes submitted match the test actually performed and the ICD-10 diagnosis codes in your chart. Spirometry for asthma should pair CPT 94010 or 94060 with ICD-10 J45.x. DLCO for ILD should pair CPT 94729 with ICD-10 J84.x. A coding mismatch can be corrected with a rebilling, often resolving the denial without a formal appeal.

Step 3: Obtain a Detailed Medical Necessity Letter

Ask your pulmonologist or ordering physician to write a letter that directly addresses the insurer's denial rationale. The letter should specify your diagnosis (using ICD-10 codes), explain why a PFT is required at this time, cite the ATS, ERS, GOLD, or GINA guidelines that support the order, and — for repeat testing — document the specific clinical question the test is designed to answer (e.g., disease progression, treatment response, pre-surgical assessment).

Step 4: Request a Peer-to-Peer Review

Many insurers offer a peer-to-peer review in which your treating pulmonologist speaks directly with the insurer's medical reviewer. This is often the fastest path to overturning a PFT denial. The clinical case for PFTs is straightforward and difficult for a medical reviewer to dismiss when a specialist is presenting it in real time. Ask your physician's office to call the insurer and request this review as soon as the denial arrives.

Step 5: Submit Your Formal Written Appeal

File a written appeal that addresses the denial reason point by point. Attach the medical necessity letter, relevant clinical records, guideline excerpts, and corrected billing documentation if applicable. For ERISA plans, you must typically exhaust this internal appeal before requesting External Independent Review: Complete Guide" class="auto-link">external review. For ACA marketplace plans, you have 180 days from the denial to file an internal appeal.

Step 6: Request Independent External Review

If your internal appeal is denied, you have the right to an Independent Review Organization (IRO) review. External reviewers in respiratory medicine almost universally find PFTs to be standard of care for the conditions they diagnose and monitor. For ACA marketplace plans, external review is required by federal law. Success rates at external review for diagnostic test denials are substantially higher than internal appeal rates.

What to Include in Your Appeal

• The denial letter and Explanation of Benefits (EOB) with the specific CPT code and denial reason identified
• Physician letter of medical necessity citing ICD-10 diagnosis codes (J44 for COPD, J45 for asthma, J84.10 for pulmonary fibrosis, I27.0 for pulmonary hypertension) and applicable ATS/ERS/GOLD/GINA guidelines
• Confirmed correct CPT codes from the provider's billing department, with documentation of the test actually performed
• Clinical records demonstrating the medical context for the test: office visit notes, prior test results, documented symptoms, medication history
• For repeat testing: documentation of the specific clinical purpose (monitoring disease progression, assessing bronchodilator response, pre-operative evaluation)

Fight Back With ClaimBack

A pulmonary function test denial is one of the most medically indefensible denials an insurer can make — the clinical evidence base for these tests is overwhelming and well-established. The key is translating that evidence into a precise appeal that matches your insurer's specific denial rationale. ClaimBack generates a professional appeal letter in 3 minutes.

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Related Reading

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Internal vs External Insurance Appeal