What R91 covers · when clinicians use it
ICD-10 code R91 identifies Abnormal findings on diagnostic imaging of lung in the U.S. ICD-10-CM clinical and billing record set. It sits within the Symptoms, Signs & Abnormal Findings chapter (R00–R99), the section that groups related diagnoses so providers, payers, and public-health agencies report them consistently. Clinicians and medical coders apply R91 when an encounter's findings match the Abnormal findings on diagnostic imaging of lung description, attaching it to the patient record so downstream insurance claims, payer audits, quality reporting, and epidemiological surveillance all reference the same standardized diagnosis. The ICD-10-CM is maintained by the Centers for Medicare & Medicaid Services and the CDC's National Center for Health Statistics, with an updated official code set released each U.S. fiscal year — always verify R91 against the current CMS/CDC release and your payer's documentation guidance before final use. This page summarizes documentation context for R91 and is a coding reference, not clinical, diagnostic, or billing advice.
ICD10 code R91 describes Abnormal findings on diagnostic imaging of lung, identifying unexplained abnormalities observed in imaging tests like MRI, CT scans, X-rays, or functional studies that require additional investigation.
Symptoms
- Brain lesions or atrophy seen on MRI – R90
- Abnormal lung nodules or masses on chest X-ray – R91
- Suspicious breast masses requiring biopsy – R92
- Unexplained findings in bones, abdomen, or soft tissues – R93
- Abnormal EEG, ECG, or pulmonary function test results – R94
Diagnosis
Findings flagged under these codes typically result from imaging modalities such as MRI, CT, ultrasound, mammography, or functional diagnostics like EEGs, ECGs, spirometry, and often prompt further targeted diagnostic or biopsy procedures.
ICD10 Code Usage
R91 is critical for billing, clinical documentation, and follow-up planning when imaging or diagnostic studies show potential pathology without yet having a confirmed diagnosis.
Related Codes
- R90 – Abnormal findings on diagnostic imaging of central nervous system
- R92 – Abnormal and inconclusive findings on diagnostic imaging of breast
- R93 – Abnormal findings on diagnostic imaging of other body structures
- R94 – Abnormal results of function studies
FAQs
Q1: What is ICD10 code R91?
A: It captures imaging or functional test findings that appear abnormal but are not yet definitively diagnosed.
Q2: Does an abnormal finding always mean disease?
A: No, some abnormalities are benign or age-related but require clarification or monitoring.
Q3: Why use a separate code for abnormal imaging?
A: It flags the need for further investigation without prematurely labeling a condition.
Q4: What happens after an abnormal imaging result?
A: Physicians may recommend follow-up imaging, biopsy, specialist referral, or additional testing based on the nature and location of the abnormality.
Q5: Are these codes used in preventive health screenings?
A: Yes, especially in breast cancer screening (R92) and lung cancer screenings (R91).
Conclusion
ICD10 code R91 is vital for documenting Abnormal findings on diagnostic imaging of lung, ensuring patients with potential abnormalities receive timely follow-up, aiding early detection of serious conditions.