Pulmonology Coding Alert

Question: How will I code interpretation of a pulmonary function test for a patient with suspected COPD if the results are abnormal? What separates the different COPD ICD-9 codes?

Texas Subscriber

Answer: Under Medicare ICD-9 coding rules, the pulmonologist can only bill for interpretation using the confirmed diagnosis of the test and not the diagnosis or symptoms that prompted the test. If the interpretation is abnormal but did not provide a definitely confirmed diagnosis, you may code the pulmonary function test with 794.2 (Nonspecific abnormal result of function study of pulmonary system) or 786.00 (Respiratory abnormality, unspecified). The signs and/or symptoms that prompted ordering the test may be reported as additional diagnoses if they are not fully explained or related to the confirmed diagnosis. If the test is normal, code for the signs and symptoms that initially prompted the test. 

As for the ICD-9 codes, a specified exacerbation along with the COPD will decide the correct ICD-9 code for reporting the condition. In cases of patients diagnosed with COPD with an exacerbation, you will report 491.21 (Obstructive chronic bronchitis with [acute] exacerbation). For COPD patients classified as obstructive “bronchitis” by the physician in the documentation/medical record, but without an exacerbation, you will report 491.20 (Obstructive chronic bronchitis without exacerbation). For otherwise unspecified COPD, you may report 496 (Chronic airway obstruction, not elsewhere classified).