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Pulmonary function test & spirometry coding guide (2026)
Pulmonary function testing is the highest-volume diagnostic family in most pulmonology practices — and one of the most frequently denied. This guide covers the core CPT codes, the documentation rule that causes most PFT denials, and how component billing works by site of service.
This guide is educational, not legal or compliance advice. CPT codes and payer rules change; verify against the current AMA CPT code set and the CMS Physician Fee Schedule before billing.
The core PFT code set
| CPT | Test | Notes |
|---|---|---|
| 94010 | Spirometry, with graphic record | The baseline study |
| 94060 | Spirometry with bronchodilator responsiveness | Pre- and post- measurements required in the record |
| 94726 | Plethysmography / lung volume measurement | Distinct from spirometry — don't substitute |
| 94729 | Diffusing capacity (DLCO) | Commonly billed with lung volumes; check payer edit pairs |
| 94618 | Pulmonary stress testing | Simple exercise-induced testing |
| 94760 / 94761 | Pulse oximetry, single / continuous | Often bundled into E/M by payers — know your payer's policy |
The rule that causes most PFT denials
Every PFT claim has two components: performing the test, and a signed physician interpretation report. Many payers deny claims outright when the interpretation isn't documented at the time of billing. The interpretation must be signed by the interpreting physician, state the clinical significance of the findings, and be in the record — “report available on request” is how denials happen.
Prevention checklist:
- Interpretation signed and filed before claim submission — make it a hard stop in the workflow.
- Interpretation states clinical significance, not just values.
- Ordering diagnosis supports medical necessity under the payer's policy.
Component billing: 26, TC, and global
Where the test happens decides how it bills. Practice-owned equipment, practice-employed staff: bill global — no modifier. Hospital or shared facility performs the test, your physician interprets: the physician bills modifier 26 (professional component) and the facility bills TC. Billing global when you only provided the interpretation is a routine denial — and occasionally a payback letter.
Medical necessity
PFT coverage is governed by payer policy and, for Medicare, by local coverage determinations (LCDs). The ordering diagnosis must support the specific test performed. Asthma and COPD evaluation, unexplained dyspnea, and pre-operative assessment are commonly covered indications — but the mapping of diagnosis code to covered test varies by payer, so confirm against the applicable LCD.
Frequently asked questions
What is CPT 94010?
Spirometry including graphic record, total and timed vital capacity, and expiratory flow rate measurement. It's the baseline pulmonary function study; use 94060 instead when bronchodilator responsiveness testing was performed.
Can 94010 and 94060 be billed together?
No — 94060 includes the spirometry, so billing both for the same session is a bundling error.
Why do payers deny PFTs for missing documentation?
Usually the signed physician interpretation. It's a required claim component, and it must exist in the record when the claim is submitted, not after the denial arrives.
Does Medicare require modifier 26 for PFT interpretation?
When the test is performed on facility equipment and the physician provides only the interpretation, yes — the professional component bills with modifier 26 and the facility bills TC. Practice-owned global testing needs no modifier.