Laterality errors in radiology reports: causes and how to catch them

Laterality errors in radiology reports are the kind of mistake that looks small on first read and turns serious on second look. A report that places a finding on the right when the image shows left, or that uses different sides in the findings and impression, may reflect nothing more than a dictation artifact. But it can also lead to a wrong side biopsy, a wrong side surgery, or removal of a healthy organ.

For operations managers at radiology groups and teleradiology services, laterality errors represent a specific category of risk worth understanding on its own terms. They are not just another report mistake. They are one of the few report errors where the clinical consequence of letting one through can be irreversible.

This article covers what causes laterality errors to appear in finished reports, how often they occur, why many go undetected and uncorrected, and what operations managers can put in place to catch them before a report submits.

What is a laterality error in a radiology report?

A laterality error occurs when the side documented in a radiology report does not match the side shown in the images. This can take several forms:

• A finding described as “right” in the report body but appearing on the left in the images
• “Left” in the findings section and “right” in the impression for the same lesion
• Laterality that is correct in one section but carried forward incorrectly into another
• A comparison reference that states the correct side but a conclusion that contradicts it
• Bilateral anatomy discussed with the correct side in the findings but omitted or reversed in the clinical recommendation

The error is not always the radiologist misreading the image. In many cases the radiologist correctly identifies the side while reading, but the final text drifts from that correct interpretation through the process of dictating, editing, and finalizing the report.

How common are laterality errors in radiology reports?

Laterality errors are rare in absolute terms. A study published in Academic Radiology reviewing more than one million reports at a single institution found a rate below 0.01%. A separate automated detection system identified 32 laterality errors over a seven month period at one facility.

That low rate is somewhat reassuring, but two other findings from the research are not.

First, around 70% of laterality errors identified in studies were graded as clinically important. These were not clerical oddities that any reasonable clinician would read past. They were errors that carried genuine potential to alter clinical management.

Second, and more concerning for operations managers: most laterality errors in one study were not corrected after they were discovered, and most were not identified at all over a one year follow up period. The errors that exist in finalized reports are not just theoretical. Many stay in the record.

For a teleradiology group reading across multiple hospitals and referring clinicians, this matters. A report goes to a clinician who may have no way to assess whether the laterality is correct without the images. If the finding is on a body part that looks symmetric on imaging and the side is wrong in the text, the clinician proceeds on the report they have.

What causes laterality errors in a finished report?

The research points to several specific mechanisms. Understanding them helps in designing a process that interrupts each one.

Speech recognition artifacts. Voice recognition is faster than conventional transcription, but it introduces a specific class of error: wrong word substitution. “Right” and “left” are short, phonetically distinct, and common. A recognition system should handle them reliably. In practice, a confident but incorrect substitution of one for the other can enter the transcript without the radiologist catching it, especially at speed or at the end of a long shift. Applied Radiology notes the higher error rate in voice recognition reports compared to conventional transcription.

Impression written separately from findings. Many radiologists complete findings and then write the impression separately, sometimes using a different dictation approach or summarizing from memory. If the findings section of a CT chest correctly documents a right lung nodule and the impression is then summarized with “left” through a slip or autocomplete, the internal contradiction may not be obvious during a quick read.

Copy forward from prior reports. Radiology operations that use prior report templates or carry forward language from previous studies inherit whatever was written in the prior. A correct prior that documented a left finding may carry “left” into a new report where the finding has changed, migrated, or resolved on the contralateral side.

Combined and bilateral reports. When a report covers bilateral anatomy or multiple findings across both sides, the risk of a laterality drift increases. More side references mean more opportunities for one to be wrong, and detecting an inconsistency is harder in a longer, more complex report. The research notes that laterality errors are most common in verbose CT and mammography reports, which tend to document multiple structures across both sides.

Editing after dictation. Reports are frequently edited, shortened, or reformatted after the initial dictation. An edit that adjusts one section without updating references in another creates the same inconsistency as a dictation error, but can be harder to attribute or detect because the image review itself was correct.

Why laterality errors often reach clients uncorrected

The clinical sign off process in most radiology groups relies on the radiologist reviewing the complete report before submitting. For obvious factual errors, that review is effective. For laterality, it is less reliable than it appears.

When a radiologist reviews a finalized report, they are re reading text they just produced. They know what they intended to write, and that knowledge makes the text harder to read critically. A laterality mismatch between findings and impression can be invisible to the person who produced the report because their mental model of the correct side fills in the discrepancy.

Manual QA processes and peer review help, but they operate retrospectively. By the time a peer reviewer sees the report, it has typically already been delivered. The ACR practice parameters establish clear expectations for accuracy in reporting, but they do not specify how to catch laterality errors at the workflow level.

Second readers and coordinator checklists can intercept errors before delivery if they are positioned correctly in the workflow, but they face the same scaling constraints as any manual process: a second reader adds time and cost, and their coverage is typically limited to a sample, not every report. As volume grows, the gap between what the process intends to catch and what it actually reviews tends to widen.

What operations managers can do to reduce laterality errors

Operations managers cannot change how speech recognition handles phonetic ambiguity or prevent radiologists from editing their own reports incorrectly. What they can change is when and how a laterality check occurs.

Move the check to before submit, not after. Most laterality errors that reach clients were not caught because the check, if it existed at all, happened after the report had already been delivered. A check that runs at finalization, before the report submits, can interrupt the error at the moment when correction is cheapest. The radiologist is still in the case. The images are still open. Fixing a laterality flag takes seconds rather than the time required to issue an amended report and follow up with the referring clinician.

Check the whole report, not just one field. Laterality in radiology reports is a consistency problem. The error often lives not in a single wrong word but in a mismatch between the findings section, the impression, and the recommendation. A check that flags “right” in one place and “left” in another for the same anatomical structure covers the full pattern rather than spot checking individual terms.

Separate laterality checks from clinical review. Clinical review requires judgment. Laterality consistency does not. A findings section that says “right” and an impression that says “left” for the same nodule is objectively inconsistent regardless of the clinical interpretation. Separating that mechanical check from the subjective clinical review allows each to happen reliably. The peer review vs automated QA comparison makes clear that these are complementary functions, not substitutes.

Track laterality callback rate as a leading indicator. Most groups track callbacks by category, but laterality corrections are sometimes buried under general accuracy callbacks. Pulling them out separately gives a cleaner view of where the process is failing and whether a change you made actually moved the number.

Audit report workflows that use copy forward. If your operation uses templates or prior report carry forward as standard practice, a laterality audit of those workflows specifically is worthwhile. The risk is concentrated there because the prior text that enters the report may have been correct for a different study and is now serving a new one where the laterality may differ.

More on how these categories connect to the broader error landscape is covered in the post on common errors in radiology reports.

How SkiaQA checks for laterality errors before a report submits

SkiaQA runs on every report at finalization. One of its checks is laterality consistency: it flags a right finding written into a left section, or sides that contradict between findings and impression, before the report submits.

The check is not a word scanner. It reads the report the way a reviewer would, looking for contradictions between what the findings say and what the impression concludes. When a flag appears, the radiologist sees it inline in the report. Most flags are resolved in the moment, without a reopen or an amended report.

Because SkiaQA runs on every report, not a sample, the coverage does not depend on shift timing, volume, or whether a second reader was available. A report finalized at 2am in the middle of a high volume teleradiology shift gets the same laterality check as one finalized at 10am with full day team support. The QA program built around it, which is described in detail in the scalable radiology QA program guide, handles the overall structure; SkiaQA handles the per report execution.

Skia stores zero patient data. Your data never leaves your PACS.

For groups that want a laterality check and the broader pre submit quality layer on every report, book a demo to see how SkiaQA fits your operation.

Frequently asked questions

How often do laterality errors occur in radiology reports?

Studies place the rate at less than 0.01% of reports. One institution reviewing over one million reports found rates below that threshold. The absolute number is low, but approximately 70% of identified laterality errors are classified as clinically important, and many go undetected and uncorrected after finalization.

What causes laterality errors in radiology reports?

The most common causes are speech recognition wrong word substitutions, impressions written separately from findings and summarized from memory, copy forward from prior reports, and edits made after dictation that update one section without updating others. Complex bilateral reports with multiple side references carry higher risk.

Are laterality errors always the radiologist’s fault?

Not always. Many laterality errors are workflow artifacts rather than clinical mistakes. The radiologist may correctly identify the correct side on the image and produce an incorrect text through the dictation and editing process. Workflow changes that catch inconsistencies before submit address the process, not the individual.

What is the best way to catch laterality errors before a report leaves?

A submit time check that reads the whole report for side consistency, comparing findings, impression, and recommendations, catches the pattern before delivery. The check needs to cover the full report rather than individual terms, and it needs to run on every report rather than a sample to be reliable as volume grows.

Does peer review catch laterality errors?

Peer review can identify laterality errors when a reviewer examines the same case. The limitation is timing and coverage: peer review typically happens after delivery on a fraction of reports. It is useful for identifying patterns and for clinical accuracy review, but it is not a reliable submit time gate for laterality consistency on every report.