Guide · checked October 2026
RADPEER scoring explained: 1, 2a, 2b, 3a and 3b
RADPEER is the American College of Radiology's peer review scale: 1 means the reviewer concurs, 2 is a discrepancy not ordinarily expected to be made (an understandable miss), 3 is a discrepancy that should be made most of the time, and an a or b modifier says whether it is unlikely or likely to be clinically significant.
The scale
- 1: concur with interpretation.
- 2: discrepancy in interpretation, not ordinarily expected to be made (understandable miss).
- 3: discrepancy in interpretation, should be made most of the time.
- Modifier a: unlikely to be clinically significant.
- Modifier b: likely to be clinically significant.
So 2a is an understandable miss unlikely to matter clinically, and 3b is a miss most radiologists would be expected to avoid that is likely to matter. ACR says scores of 2b, 3a and 3b should go to internal review first, for example by a chair, medical director or QA committee.
How RADPEER works in the US
ACR describes RADPEER as its peer review programme for routine interpretation: scoring a prior study while reading a new one counts as a peer review event, and scores are submitted through a secure website. ACR's page says it is not accepting applications from international facilities, so UK departments cannot join the programme itself, though many borrow the scale.
The UK view on scoring
The RCR's 2020 REALM standards do not recommend scoring or grading suspected errors in learning meetings, warning that a scoring culture can feed a blame culture. The 2026 working draft for consultation keeps that position. A department can still use a scale inside a structured peer review programme while keeping REALMs score-free.
What a score does not mean
- A 2 is not "no error": it is a discrepancy that is understandable.
- A b modifier is a judgement of likely significance, not a record of patient harm.
- A score is not a disciplinary finding; ACR routes the higher scores to internal review.
Where RadQA fits
RadQA records peer review scores as 1, 2a, 2b, 3a or 3b, each with its plain-language description, and marks every score other than 1 as a discrepancy and the b scores as clinically significant. Analytics show the score distribution and discrepancy rate over a range, by modality and, for users allowed to see it, by radiologist. Where a model compares a current report with a prior, it suggests a score for a person to accept or change.
RadQA is not affiliated with ACR's RADPEER programme. RadQA is a pilot. It is a quality-assurance assistant, not a diagnostic device, and it does not replace radiologist reporting or clinical judgement.
Questions
Which RADPEER scores need review?
ACR says 2b, 3a and 3b should go to internal review first, for example by a chair, medical director or QA committee.
Can UK hospitals join RADPEER?
ACR's page says it is not accepting applications from international facilities.
Sources
Official pages, checked October 2026. Guidance changes, so check the current version before you rely on it.
General information for healthcare managers and clinical teams, checked October 2026. It is not legal, regulatory or clinical advice; follow the current official guidance and your organisation's own policies. No patient data is used in these examples. RadQA is a quality-assurance assistant for imaging departments. It is not a diagnostic device and does not replace radiologist reporting or clinical judgement. Validate against your own systems and local governance before production use.