Pulmonology Billing has never been simple. Between the complexity of respiratory diagnosis coding, the documentation requirements for pulmonary function testing, the prior authorization hurdles on high-cost biologics, and the ever-shifting payer policies on sleep studies billing for a pulmonology practice requires a level of specificity that leaves very little room for error.
If you manage billing for a pulmonology practice or you are a pulmonologist who’s ever looked at your denial rate and felt a familiar frustration this guide is built for you. We’re covering the CPT codes that matter most, the ICD-10 codes that pair with them, where documentation tends to fall short, and what’s driving denials in pulmonology practices right now.
Essential CPT Codes for Pulmonology Billing in 2026
This is not every code a pulmonologist might ever bill it’s the core set that drives the most revenue and creates the most billing questions in a typical practice.
Evaluation and Management Codes
Office visits are the foundation of any pulmonology practice’s billing. Under the current E&M guidelines which have been in effect since 2021 and remain current in 2026 office visits for established patients are coded based on either total time or medical decision-making complexity.
For pulmonology billing, the most commonly billed established patient codes are:
CPT 99213: Low complexity visit, 20-29 minutes total time. Appropriate for stable patients with a single well-controlled condition, such as a patient with mild, well-managed asthma coming in for a routine check.
CPT 99214: Moderate complexity visit, 30-39 minutes total time. This is where most pulmonology established patient visits land. A patient with COPD who has two or three ongoing issues, medication adjustments, or a new symptom to evaluate. The reality is that many pulmonology practices are undercoding here defaulting to 99213 out of habit when the documentation clearly supports 99214.
CPT 99215: High complexity visit, 40-54 minutes total time. Appropriate for patients with multiple chronic conditions, significant comorbidities, or major treatment decisions being made. End-stage COPD, pulmonary fibrosis with declining function, complex pulmonary hypertension management these are 99215 encounters when documented correctly.
For new patients, the corresponding codes are 99202 through 99205, with similar complexity and time thresholds.
One practical note: Pulmonology patients are often medically complex enough to support a higher E&M level than what’s being billed. A quick internal audit of your E&M distribution what percentage of visits are 99213 versus 99214 versus 99215 can tell you a lot about whether your coding reflects the actual clinical work being done.
Pulmonary Function Testing CPT codes
Pulmonary function testing is one of the highest-value procedure categories in pulmonology, and it’s also one where billing errors and missed codes are common.
| CPT Codes | Procedure | Description |
|---|---|---|
| 94010 | Spirometry, including graphic record, total and timed vital capacity, expiratory flow rate measurement | This is the basic spirometry code pre and post-bronchodilator testing falls under this code when performed together with 94060. |
| 94060 | Bronchodilation responsiveness, spirometry before and after bronchodilator | Billed in addition to 94010 when bronchodilator response is being assessed. |
| 94070 | Prolonged postexposure evaluation of bronchospasm with multiple spirometric determinations | Used for methacholine or other bronchoprovocation challenges. |
| 94150 | Vital capacity, total. | Vital capacity, total. |
| 94200 | Maximum breathing capacity, maximal voluntary ventilation. | Maximum breathing capacity, maximal voluntary ventilation. |
| 94375 | Respiratory flow-volume loop. | Respiratory flow-volume loop. |
| 94726 | Plethysmography for determination of lung volumes and/or airway resistance | This is your body plethysmography code: total lung capacity, residual volume, functional residual capacity. |
| 94727 | Gas dilution or washout for determination of lung volumes and/or distribution of ventilation | Helium dilution or nitrogen washout for lung volumes. |
| 94729 | Diffusing capacity — DLCO | One of the most commonly performed pulmonary function tests, and one that’s sometimes billed incorrectly or not billed at all when it’s performed as part of a comprehensive PFT battery. |
| 94621 | Cardiopulmonary exercise testing | Includes measurements of minute ventilation, CO2 production, O2 uptake, and ECG recordings. |
When multiple PFT components are performed in the same session, each separately billable component should be coded. The common mistake is billing only the “main” test and missing the additional components that were also performed and interpreted.
Bronchoscopy CPT Codes
Bronchoscopy is one of the highest-reimbursing procedure categories in pulmonology billing, and the coding is more nuanced than it looks.
| CPT Code | Procedure | Description |
|---|---|---|
| 31622 | Bronchoscopy, rigid or flexible, including fluoroscopic guidance, when performed; diagnostic, with or without cell washing (separate procedure) | This is the base bronchoscopy code |
| 31623 | Bronchoscopy with brushings | Bronchoscopy with brushings |
| 31624 | Bronchoscopy with bronchial alveolar lavage | Bronchoscopy with bronchial alveolar lavage |
| 31625 | Bronchoscopy with bronchial or endobronchial biopsy | Bronchoscopy with bronchial or endobronchial biopsy |
| 31627 | Bronchoscopy with computer-assisted, image-guided navigation | Bronchoscopy with computer-assisted, image-guided navigation |
| 31628 | Bronchoscopy with transbronchial lung biopsy, including fluoroscopic guidance when performed; single lobe | Bronchoscopy with transbronchial lung biopsy, including fluoroscopic guidance when performed; single lobe |
| 31629 | Bronchoscopy with transbronchial needle aspiration biopsy | Bronchoscopy with transbronchial needle aspiration biopsy |
| 31632 | Bronchoscopy with transbronchial lung biopsy; each additional lobe | Billed in addition to 31628 |
| 31635 | Bronchoscopy with removal of foreign body | Bronchoscopy with removal of foreign body |
| 31641 | Bronchoscopy with destruction of tumor | Bronchoscopy with destruction of tumor |
The most common bronchoscopy billing error is failing to code the base bronchoscopy separately from the additional procedures when multiple procedures are performed through the same scope. Know your add-on codes and your bundling rules some combinations are appropriate and separately billable, others are bundled by NCCI edits and cannot be unbundled even with a modifier.
Thoracentesis and Pleural Procedures
CPT 32554: Thoracentesis, needle or catheter, aspiration of the pleural space; without imaging guidance.
CPT 32555: Thoracentesis with imaging guidance. If ultrasound is used, document it clearly image documentation must be stored and the note must reflect real-time imaging guidance.
CPT 32557: Pleural drainage, percutaneous, with insertion of indwelling catheter; with imaging guidance.
Sleep Medicine CPT Codes
Many pulmonologists oversee sleep medicine services, and this is an area where billing complexity and payer scrutiny run especially high.
| CPT Codes | Procedure |
|---|---|
| 95800 | Sleep study, unattended, simultaneous recording of heart rate, oxygen saturation, respiratory analysis, and sleep time |
| 95801 | Sleep study, unattended, minimum recording including heart rate, oxygen saturation, and respiratory analysis |
| 95808 | Polysomnography; any age, with 1-3 additional parameters of sleep |
| 95810 | Polysomnography; age 6 years or older, attended, with 4 or more additional parameters of sleep |
| 95811 | Polysomnography with continuous positive airway pressure titration (CPAP) |
| 95806 | Home sleep apnea testing |
| 95782 / 95783 | Polysomnography for patients under 6 years |
Sleep study interpretation fees billed separately when the interpreting physician is not the performing facility are commonly missed. If your pulmonologist is reading sleep studies performed at a hospital or independent sleep center, the interpretation is separately billable under the professional component using modifier 26.
Ventilator Management Codes
CPT 94002: Ventilation assist and management, initiation of pressure or volume-preset ventilators for assisted or controlled breathing; hospital inpatient/observation, initial day.
CPT 94003: Ventilation assist and management; hospital inpatient/observation, each subsequent day.
CPT 94004: Ventilation assist and management; nursing facility, per day.
These codes are often underbilled in practices where pulmonologists round on ventilated patients. Each day of ventilator management is separately billable. Make sure your rounding documentation reflects active ventilator management decisions, not just a note that the patient is on the vent.
Key ICD-10 Diagnosis Codes for Pulmonology
Specificity in diagnosis coding is critical in pulmonology billing. Payers look hard at whether your diagnosis codes match the clinical picture and support the procedures billed.
COPD and Respiratory Conditions
J44.0: COPD with acute lower respiratory infection
J44.1: COPD with acute exacerbation
J44.9: COPD, unspecified
J43.9: Emphysema, unspecified
J45.20: Mild intermittent asthma, uncomplicated
J45.21: Mild intermittent asthma with acute exacerbation
J45.30: Mild persistent asthma, uncomplicated
J45.40: Moderate persistent asthma, uncomplicated
J45.41: Moderate persistent asthma with acute exacerbation
J45.50: Severe persistent asthma, uncomplicated
J45.51: Severe persistent asthma with acute exacerbation
One coding note that matters for COPD: always code to the highest level of specificity. J44.9 should only be used when the record genuinely doesn’t support a more specific code. If there’s an acute exacerbation, J44.1 is the right code. Defaulting to J44.9 across the board is a pattern that auditors notice.
Interstitial Lung Disease
J84.10: Pulmonary fibrosis, unspecified
J84.112: Idiopathic pulmonary fibrosis
J84.116: Cryptogenic organizing pneumonia
J84.17: Other interstitial pulmonary diseases with fibrosis in diseases classified elsewhere
J84.89: Other specified interstitial pulmonary diseases
Pulmonary Vascular Disease
I27.0: Primary pulmonary hypertension
I27.20: Pulmonary hypertension, unspecified
I27.21: Secondary pulmonary arterial hypertension
I27.29: Other secondary pulmonary hypertension
I26.09: Other pulmonary embolism without acute cor pulmonale
I26.99: Other pulmonary embolism with acute cor pulmonale
Sleep Disorders
G47.30: Sleep apnea, unspecified
G47.31: Primary central sleep apnea
G47.33: Obstructive sleep apnea (adult)
G47.37: Central sleep apnea in conditions classified elsewhere
G47.19: Other hypersomnia
Pleural Conditions
J90: Pleural effusion, not elsewhere classified
J91.0: Malignant pleural effusion
J94.0: Chylous effusion
J94.8: Other specified pleural conditions
J93.11: Primary spontaneous pneumothorax
J93.12: Secondary spontaneous pneumothorax
Lung Malignancy
C34.10: Malignant neoplasm of upper lobe, bronchus or lung, unspecified side
C34.11: Malignant neoplasm of upper lobe, right bronchus or lung
C34.12: Malignant neoplasm of upper lobe, left bronchus or lung
C34.30: Malignant neoplasm of lower lobe, unspecified side
C78.00: Secondary malignant neoplasm of unspecified lung
Common Denial Reasons in Pulmonology Billing and How to Fix Them
Medical Necessity Denials on Pulmonary Function Tests
PFTs get denied for medical necessity more often than most pulmonologists realize, especially when the diagnosis code on the claim doesn’t clearly connect to the test ordered. A spirometry performed on a patient whose chart shows only hypertension and diabetes as active diagnoses is going to raise questions. The respiratory diagnosis needs to be on the claim.
Fix: Make sure the ordering diagnosis for every PFT is a respiratory condition documented in the clinical note. If the patient is being evaluated for a new respiratory symptom, code the symptom dyspnea (R06.09), chronic cough (R05.9), wheezing (R06.2) until a definitive diagnosis is established.
Bronchoscopy Denied for Insufficient Documentation
Bronchoscopy is an area of high payer scrutiny. Denials commonly occur when the operative report doesn’t include sufficient detail about the findings, the indication for the procedure isn’t clearly documented, or the report is templated in a way that looks generic.
Fix: Every bronchoscopy report needs to describe the specific indication, the anatomical findings at each airway segment examined, what procedures were performed and where, specimen information if biopsies were taken, and any complications. A procedure note that reads the same for every patient is a documentation problem that will catch up with you.
Sleep Study Prior Authorization not Obtained
Commercial payers almost universally require prior authorization for attended polysomnography. Getting the sleep study done and then submitting the claim without auth is one of the most avoidable denials in the specialty.
Fix: Build authorization verification into your sleep study scheduling workflow as a hard stop. The study doesn’t get scheduled until auth is confirmed. Document the authorization number and attach it to the claim.
Modifier 26 Missing on Interpreted Studies
When a pulmonologist interprets studies performed at a facility they don’t own sleep studies, PFTs, or imaging the professional component needs to be billed with modifier 26. Without it, the claim either denies or gets paid at the wrong rate.
Fix: Audit your interpretation billing quarterly. Identify every study type your physicians are reading and make sure the billing correctly reflects whether it’s a global, professional component (26), or technical component (TC) bill.
Duplicate Billing on PFT Components
Some practices accidentally bill overlapping PFT codes for example, billing 94726 and 94727 together when only one method of lung volume measurement was used. NCCI edits catch many of these, but not all payers apply them consistently.
Fix: Your billing team needs to understand which PFT components are separately billable when performed together and which are mutually exclusive. When in doubt, pull the NCCI edit table and check the specific code pair.
Undercoded E&M Visits
This isn’t a denial, but it’s a revenue leak that’s just as real. Many pulmonology billing practices run a higher percentage of 99213 codes than the clinical complexity of their patient population actually supports. A patient with COPD, pulmonary hypertension, and sleep apnea being managed at the same visit is not a 99213.
Fix: Run an E&M distribution report and compare your coding pattern to national benchmarks for pulmonology billing. If your 99214 and 99215 rates are lower than average, that’s a signal worth investigating.
Frequently Asked Questions
What is the most commonly undercoded CPT in Pulmonology Billing?
Hands down, it’s the E&M visit. Pulmonology patients are medically complex, and the clinical work done during a typical established patient visit managing multiple chronic conditions, reviewing test results, adjusting medications, and coordinating care often supports 99214 or even 99215. Many practices default to 99213 out of habit, leaving meaningful revenue behind on every visit.
Can pulmonary function tests be billed on the same day as an office visit?
Yes. PFTs performed on the same day as an E&M visit can be billed separately. The E&M should have modifier 25 if the office visit is a separately identifiable service beyond the pre-procedure evaluation for the PFT. The PFT result should be referenced in the office visit note, showing that you reviewed and interpreted it as part of your clinical decision-making.
How should COPD exacerbations be coded in pulmonology billing?
When a patient presents with an acute COPD exacerbation, J44.1 is the primary diagnosis code. If there’s a concurrent lower respiratory infection, J44.0 should be considered. Code additional comorbidities, such as respiratory failure, hypoxia, or cor pulmonale as secondary diagnoses when documented and clinically relevant to the encounter. Specificity matters here because it affects both payment and risk adjustment.
What documentation is required to bill for home oxygen?
To bill for home oxygen setup and support the payer’s coverage criteria require your documentation to include: a qualifying diagnosis, oxygen saturation measurement at rest (and with exertion if ordering ambulatory O2), the specific flow rate and delivery system ordered, and a certificate of medical necessity (CMN) completed according to the payer’s requirements. Medicare has very specific qualifying thresholds oxygen saturation at or below 88% at rest, or 89% with qualifying criteria that must be documented in the medical record.
Conclusion
Every day your pulmonology billing team sees patients with serious, chronic, complex conditions. The clinical work is demanding. The last thing your practice needs is billing complexity on top of it missed codes, prior auth denials, documentation deficiencies, and aging AR on high-value procedures.
The practices that do pulmonology billing well aren’t necessarily the ones with the biggest billing departments. They’re the ones with clear documentation standards, consistent coding workflows, and a billing partner who understands what pulmonology actually looks like at the claim level.
At Med Bridge LLC, pulmonology billing services is one of our core specialties. We work with practices to optimize E&M coding, capture procedure revenue that’s being missed, build prior authorization workflows that prevent denials before they happen, and work aged claims back to resolution.
