Pulmonology Coding Alert

Look for clues in the method used: injection or inhalation.

When your pulmonologist orders a ventilation/perfusion scan (or VQ scan) to help rule out a suspected pulmonary embolism, you might encounter terms such as "MAA" and "DTPA" in the physician's notes, and question why you can't find them in the code's descriptors. This can be confusing, and can cause coding inconsistency -- putting your practice at compliance or financial risk.

In order to code with consistency, you will need to confirm if the physician provided a perfusion or ventilation service. Check out these lung scan language refresher to help you with your 'whys and hows':

Proceed With An Injection Using 78580

If the pulmonologist wants to learn how well a patient is getting oxygen into their blood, he'd generally like to measure two things: how well the blood is getting down into the capillaries surrounding the alveoli in the lungs (perfusion), and how well the oxygen is getting down into those same alveoli (ventilation). A pair of nuclear scan tests -- pulmonary ventilation/perfusion scan -- will accomplish this purpose.

Definition: A VQ scan uses inhaled and injected radioactive material called radioisotopes to measure breathing (ventilation) and circulation (perfusion). The physician may perform these tests separately or together.

During a perfusion scan, a provider injects radioactive albumin into the patient's vein. This material travels through the vascular system, allowing for a scan of the patient's lungs as blood flows through them to detect the location of the radioactive particles. To describe a service that is specific to perfusion, you would use 78580 (Pulmonary perfusion imaging, particulate).

Look for the injection of the radioisotope to differentiate between perfusion and ventilation. This is unique to perfusion. The physician would likely refer to macroaggregated albumin (the radioactive particles injected into the patient's vein) in her report of a perfusion scan service. You may see it documented as "Tc-99m- MAA, MAA" or "Technetium MAA". The term "macrospheres" can also narrow your choice to a perfusion study.

Relate Ventilation Study To Aerosol and Gaseous Radioactivity

Say the documentation says the patient inhaled the radioactive substance for a lung scan -- instead of getting it injected -- you would choose from the following ventilation study codes:

• 78586 -- Pulmonary ventilation imaging, aerosol; single projection
• 78587 -- ... multiple projections (e.g., anterior, posterior, lateral views)
• 78591 -- Pulmonary ventilation imaging, gaseous, single breath, single projection
• 78593 -- Pulmonary ventilation imaging, gaseous, with rebreathing and washout with or without single breath; single projection
• 78594 -- ... multiple projections (e.g., anterior, posterior, lateral views).

What happens: During a ventilation study, the provider places a mask over the patient's mouth and nose so he breathes in the radioactive material while images are taken to measure air flow in and out of the lungs.

When determining if the physician performed a ventilation study, you may see clear documentation, for instance the word "ventilation." Also, you should know if the patient inhaled a radioactive gas (generally xenon), or if the patient actually inhaled oxygen that had been aerosolized with particles of a radioactive substance. You would bill 78586 or 78587 for aerosol study; 78591, 78593, or 78594 for gaseous.

The key term to look for indicating aerosol is "DTPA," the radioactive aerosol the provider has the patient inhale, says Becki Garaud, CPC, CPCE/M, RCC, compliance education and coding trainer for the University of Washington Physicians and Children's University Medical Group Compliance Program. Other terms you might see indicating aerosol include "Technetium DTPA", "particulate," and "mist."

Meanwhile, you may identify gaseous ventilation studies from referencesto the gas used, typically xenon gas (such as Xenon-133 or Xe 133), says Garaud. Another possibility is krypton gas (Krypton-81 or Kr 81), although you may not see this much in practice.

Rebreathing vs Washout: More Clues To Gaseous Ventilation Service

CPT® further distinguishes gaseous ventilation studies by whether the patient takes only a single breath or the patient does rebreathing and washout with plain oxygen.

"Rebreathing" is inhalation of the gasses previously exhaled. "Washout" is the elimination of the radioisotope from the lungs. The xenon gas exams typically consist of three phases:

1. a single breath -- the patient takes a single deep inhalation

2. rebreathing -- the patient takes normal breaths while rebreathing a mix of oxygen and xenon

3. washout -- the patient breathes room air while exhaling the xenon, clearing the lungs of the radioactive gas.

The physician will usually mention "air trapping," "gas trapping," or "clearance" when a washout has been part of the exam.

Don't Forget The Combo 78588

Perfusion and lung ventilation scans almost always go together. A pulmonologist would often perform these procedures jointly to detect a characteristic pattern of perfusion deficits. Together, these procedures provide an accurate noninvasive screening test both for the detection of emboli and for documentation of resolution during and after therapy. In this case, you would be safe coding 78588 (Pulmonary perfusion imaging, particulate, with ventilation imaging, aerosol, 1 or multiple projections), which combines codes 78580 and 78586.

CPT® 78588 describes a combined procedure to determine both pulmonary perfusion and ventilation. You would report 78588 (Pulmonary perfusion imaging, particulate, with ventilation imaging, aerosol, 1 or multiple projections) when a patient is imaged twice: once after inhalation of a radioactive aerosol to determine pulmonary ventilation and again after injection of a radioactive particulate to determine lung perfusion.

Important: You should note that the code descriptor for 78588 includes the phrase "1 or multiple projections." This means you should report 78588 regardless of the number of projections that were performed as part of the pulmonary perfusion procedure. This helps eliminate the misuse of modifier 52 (Reduced services) to indicate reduced services. For instance, if you do only one part of the 78588 procedure, you can just report the perfusion code 78580 or the ventilation code (78586) -- no need for you to append modifier 52.