Pulmonology Coding Alert

Combine plethysmography and spirometry for a complete PFT.

Spirometry receives a lot of attention in pulmonology coding, as it is performed often. But before you report it, you should also pay attention to another pulmonary function test (PFT) that is useful in determining if the patient is suffering from an obstructive or restrictive lung condition.

Learn about plethysmography and understand how to locate the correct codes for it and for other PFT codes when the procedures are performed together.

Examine Spirometry’s and Plethysmography’s Differences

Spirometry is a PFT that measures how much air the patient exhales and how fast the patient blows air out of their lungs.

Plethysmography, or lung volume, is a PFT in which the pulmonologist measures the amount of air in the patient’s lungs after inhaling deeply. The physician also measures any remaining air in the lungs after the patient exhales.

“Plethysmography is the most accurate way to measure the amount of air your lungs can hold and the amount of air that remains in your lungs after you force out as much as you can,” says Carol Pohlig, BSN, RN, CPC, manager of coding and education in the department of medicine at the Hospital of the University of Pennsylvania in Philadelphia.

A provider might order plethysmography to assess the patient’s lung or airway symptoms, which include:

• Cough
• Shortness of breath
• Wheezing
• Difficulty inhaling deeply
• Chest pain, pressure, or tightness

“Typically, plethysmography is performed in conjunction with spirometry for ‘complete pulmonary function testing’ because the pairing of information (how much air your lungs can hold and how well you move air in and out of your lungs when you breathe) will help determine the type of problem (obstructive vs. restrictive) and the corresponding treatment plan,” Pohlig says.

Obstructive conditions cause the patient’s airways to narrow making it difficult for air to flow out of your lungs. Asthma, bronchitis, and emphysema are examples of obstructive conditions, which can reduce the amount of air the patient’s lungs can hold. Patients diagnosed with scleroderma, sarcoidosis, pulmonary fibrosis, and interstitial lung diseases will also suffer from restrictive conditions.

Cracking the Code on Plethysmography

The CPT^® code set features two lung volume measurement codes — one for plethysmography and one for gas or nitrogen washout. You’ll assign 94726 (Plethysmography for determination of lung volumes and, when performed, airway resistance) when the pulmonologist performs plethysmography to measure the patient’s lung volume. If the provider administers a gas mixture to assess the lung volume, then you’d assign 94727 (Gas dilution or washout for determination of lung volumes and, when performed, distribution of ventilation and closing volumes) for the procedure.

Code 94726 includes total lung capacity, residual volume, functional residual capacity, and airway resistance measurements. Physicians will use helium dilution or nitrogen (N₂) washout with 94727 to assess lung volumes, closing volume, and distribution of ventilation.

If the provider performs complete pulmonary function testing with a plethysmography test and a spirometry test, you’ll assign one of the lung volume assessment codes listed above as well as one of the following spirometry codes:

• 94010 (Spirometry, including graphic record, total and timed vital capacity, expiratory flow rate measurement(s), with or without maximal voluntary ventilation)
• 94060 (Bronchodilation responsiveness, spirometry as in 94010, pre- and post-bronchodilator administration)
• 94070 (Bronchospasm provocation evaluation, multiple spirometric determi­nations as in 94010, with administered agents (eg, antigen[s], cold air, methacholine))

Plethysmography and spirometry procedure codes aren’t bundled together, so you won’t need modifiers to report the codes together. “There are no National Correct Coding Initiative (NCCI) procedure-to-procedure (PTP) edits that prohibit 94726 or 94727 from being reported with either 94010, 94060, or 94070,” Pohlig says.

Put Your Plethysmography Knowledge Into Action

Examine the scenario below and assess your newfound understanding to assign the correct codes for the situation.

Scenario: A 65-year-old patient presents to a pulmonology practice with complaints of shortness of breath and difficulty breathing, especially during physical activities. The patient also mentioned fatigue and a chronic cough and confessed to a current 40-year smoking history. The pulmonologist performed a lung volume test and interpreted the results, which indicated a reduced lung volume. The test results were consistent with an obstructive condition, so the physician administered a bronchodilation test. After reviewing the bronchodilation test results, the pulmonologist confirmed chronic obstructive pulmonary disease (COPD).

Starting with the procedure, the pulmonologist performed plethysmography and a bronchodilation test. This leads you to assign 94726 and 94060 for the physician’s procedures.

Expert tip: “Paying attention to the details of the testing is key, especially when trying to select between 94010 and 94060 or 94726 and 94727,” Pohlig says. She adds that the testing location also factors into whether you can bill for global services or the professional component using modifier 26 (Professional component). In this case, the pulmonologist provided the services in a private office rather than an outpatient hospital department, which means you can bill for the global services without appending a modifier for the professional component.

Next, you’ll turn to the ICD-10-CM code set to identify the diagnosis codes. The pulmonologist diagnosed the patient with COPD after reviewing the test results, factoring in the patient’s symptoms and smoking history.

You’ll assign J44.9 (Chronic obstructive pulmonary disease, unspecified) for the COPD diagnosis, unless the pulmonologist documents the diagnosis with greater specificity. The patient also confessed to smoking cigarettes for 40 years, which you’ll report with F17.210 (Nicotine dependence, cigarettes, uncomplicated).