Nonspecific abnormal results of pulmonary function study

This code signifies abnormal findings from tests measuring lung function, such as spirometry, lung volumes, or diffusing capacity, when the specific underlying cause of the abnormality has not yet been definitively diagnosed. It indicates that the patient's respiratory system is not functioning within normal parameters, but further investigation is required to pinpoint the etiology.

Use this code when pulmonary function tests (PFTs) show results outside the normal range, but the physician's documentation does not specify a definitive diagnosis like asthma, COPD, or restrictive lung disease. It is appropriate for initial PFT interpretations where the findings are abnormal but non-diagnostic, prompting further workup.

• Do not use this code if a specific diagnosis explaining the abnormal PFTs is documented.
• Always sequence this code after any definitive diagnoses that are present.
• Look for documentation indicating "abnormal PFTs," "nonspecific ventilatory defect," or "abnormal spirometry" without a clear diagnostic conclusion.