R91 is a non-billable ICD-10 code for Abnormal findings on diagnostic imaging of lung. It should not be used for HIPAA-covered transactions as a more specific code is available to choose from below.
A 3-character code is to be used only if it is not further subdivided. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7 th character, if applicable.