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Pulmonology Coding Alert

Take the Mystery out of Coding for Hypersensitivity Pneumonitis

Published on Sat Feb 01, 2003

If you're tired of stressing about how to code for the numerous tests your doctor uses to diagnose occupational antigen diseases, just remember that selecting the appropriate diagnosis code can solve the mystery behind reporting separate pulmonary function tests and E/M services.

Because environmental antigens find their unsuspecting human hosts in a broad range of everyday places, pulmonologists face a growing number of mysterious cases that they may misdiagnose and report as common respiratory problems, such as asthma. Dust in the air (whether inorganic, such as silica, or organic, such as tree bark, pigeon droppings and mold) infiltrates the human body and causes the immune system to make antibodies, says Anthony Marinelli, MD, FCCP, chairman of the American Thoracic Society's Clinical Practice Committee. These antibodies attach to the antigens, and the antigens go through the body attacking organs, often the lungs.

When a patient has a Type III allergic reaction to environmental allergens and develops local inflammation that causes tissue damage, the pulmonologist should diagnose the patient as having a common occupational antigen disease hypersensitivity pneumonitis. The steps that a pulmonologist must take to properly diagnose this disease, however, can lead to complicated coding issues.

Sift through the Numerous Diagnosis Codes

Hypersensitivity pneumonitis is an inflammatory lung disorder that is often referred to as extrinsic allergic alveolitis (EAA). The disorder is the result of long-term or intense exposure to environmental antigens, such as inorganic dust and other occupational antigens. You will encounter patients with this disease if you practice in certain areas of the country, such as cities with nearby farms or factories, says Jeffrey Berman, MD, FCCP, executive director of the Florida Pulmonary Society. Symptoms can include fever (780.6), shortness of breath (786.05), chest pain (786.50), weight loss (783.21) and fatigue (780.79), Marinelli says. Once the pulmonologist definitively diagnoses the patient with EAA, you should code to the highest level of specificity.

The ICD-9 manual covers EAAin the 495.x series (Extrinsic allergic alveolitis) and differentiates among antigens by using a fourth digit:

  • 495.0 Farmers'lung

  • 495.1 Bagassosis

  • 495.2 Bird-fanciers'lung

  • 495.3 Suberosis

  • 495.4 Malt workers'lung

  • 495.5 Mushroom workers'lung

  • 495.6 Maple bark-strippers'lung

  • 495.7 "Ventilation" pneumonitis

  • 495.8 Other specified allergic alveolitis and pneumonitis

  • 495.9 Unspecified allergic alveolitis and pneumonitis.

    Code for E/M and Other Procedures Separately

    "In pulmonary medicine, it is thought that 70 percent of the time the patient's history gives the diagnosis," Marinelli says. Apatient may present in your office with varying symptoms that could be confused with other respiratory problems, so the pulmonologist will usually take an in-depth history, perform a thorough exam and order several diagnostic tests.

    For example, a 35-year-old male presents in the office with symptoms that include a cough (786.2), fever, fatigue and weight loss. Aphysical exam may reveal crackles in the lung (786.7), wheezing (786.07) and shortness of breath. Suspecting some type of environmental antigen, the pulmonologist obtains an extensive history that includes an analysis of the patient's past and present occupational settings, pets and hobbies. The patient reports that he has been working several months in a pet store that sells various kinds of birds. Given this history and the results of a comprehensive exam, the physician decides to perform several tests that will help to definitively diagnose EAA.

    Bronchoscopies (31622, 31623, 31624 and 31628), pulmonary function tests (94010, 94240, 94375 and 94720) and chest x-rays (71010-71035) are some of the most common tests, Berman says. Several other tests that the pulmonologist may order can be useful in diagnosing EAA:

  • Complete blood count (85025-85027)

  • Antibody blood tests (86001, 86003)

  • High-resolution chest computed tomography (71275)

  • Oxygen saturation assessment (94760, 94761)

  • Prolonged postexposure evaluation (94070, 95070)

  • Antigen challenge tests (95071)

  • Skin testing (95004-95010).

    For example, the physician performs several pulmonary function tests (PFTs), including spirometry (94010), flow volume loop (94375), lung volume (94240) and diffusing capacity (94720). He also performs an antigen challenge test (94070, 95071) and a blood workup (86001, 85025). The Physician Fee Schedule designates each of these services, excluding the lab tests and 94760, as status "A," which means they are separately payable from other services performed on the same day, unless the Correct Coding Initiative (CCI) bundles them.

    You would code for the appropriate level of E/M care documented (99205-99215), taking into account the in-depth history, examination and level of medical decision making. You cannot bill for the laboratory tests but can report some of the other tests in addition to the E/M visit. There is one exception in that you cannot report 94760 on the same day as another payable service, and you should not report 95070-95071 if you work in an inpatient or outpatient hospital and the test is performed in a PFT lab. Be sure to append modifier -25 (Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure or other service) to the E/M code. Take a look at the CCI to determine which codes it bundles into more comprehensive procedures. Do not report these separately, unless appropriate.

    In the scenario above, report the highest-valued procedure first and list the other procedures next:

  • 992xx-25

  • 94070

  • 94720

  • 94240

  • 95071.

    You would not report 94010 or 94375 because CCI bundles them into the more-comprehensive 94070 code. The only time you would report these codes separately is when the pulmonologist performs the procedures for separate and distinct reasons. For example, 94010 is the first test done, and it indicates a problem that requires additional testing with the prolonged postexposure test (94070).

    You would code this scenario as 94070, 94010-59 (Distinct procedural service).

    Putting the Pieces Together

    So, what symptoms will tell the physician to diagnose and code for hypersensitivity pneumonitis? Most patients will show a restriction on spirometry and lung volume, a low diffusing capacity, and raised levels of IgG antibodies. Some people with hypersensitivity also have Type I and IV allergic reactions that result in further indications. For example, the patient would have raised IgE antibodies. When given a challenge test, the patient may wheeze a few minutes after the test and then wheeze again 8-10 hours later, showing the immediate and delayed components of the disease. When the physician sees these results and correlates them with the patient's occupational history, he or she would diagnose and report the corresponding EAAcode, Marinelli says. For the patient working in a pet store, the diagnosis would be 495.2 (Bird-fanciers' lung).

    Treatment includes immediately removing the patient from the environment that causes the problem, and, in severe cases, the physician may prescribe steroids. Pulmonologists may even deal with patients who enter into a critical-care state as a result of an allergic reaction to environmental antigens, Marinelli says. In rare circumstances like this, you should report critical-care codes (99291-99292) for any time spent monitoring and treating the patient.

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