Misread Scan, Biopsy or Histopathology
A misread biopsy, scan or histopathology slide is one of the most serious ways a cancer diagnosis goes wrong in Ireland. This page explains misread biopsy negligence and how a false negative on a scan or a tissue sample can found a cancer claim. It is cancer-specific. Our general guide to pathology and laboratory error claims covers laboratory mechanics. A separate page deals with test results not followed up, where a correct result was simply never acted on. Here the focus is narrower. The image or sample was looked at, and it was read wrong.
Quick answer: A misread scan or biopsy can found a cancer negligence claim in Ireland if the misreading fell below the Dunne standard for a competent radiologist or pathologist, and the delay caused avoidable harm. A mistake on its own isn't enough.
Contents
What is a misread scan, biopsy or histopathology?
A misread scan, biopsy or histopathology result is a diagnostic interpretation error. A radiologist or pathologist examines the image or tissue and reports it as normal or benign when cancer was present, or grades the cancer wrongly. The test was done. The reading was at fault.
This failure isn't the same as a doctor failing to order a test. It also isn't the same as a correct report that was filed and never acted on. Those are different claims with their own pages. A misread sits inside the reading itself, in the radiology reporting room or the pathology laboratory.
In Irish cancer cases, a misread tends to fall into one of four patterns. Knowing which pattern applies shapes the evidence and the experts a claim needs.
| Type of error | What happens | Cancer example |
|---|---|---|
| Perceptual | The finding is visible on the image or slide, but the reader does not perceive it, often through fatigue, distraction or excessive caseload. | A lung nodule present on a CT scan is not noticed and the scan is reported as clear. |
| Cognitive or interpretive | The finding is seen, but its meaning is misjudged. | A suspicious spiculated mass is recorded as a benign cyst. |
| Sampling (pre-analytical) | The biopsy does not capture the malignant tissue, so the slide genuinely contains no cancer. | An inadequate core biopsy misses the tumour and returns a false-negative report. |
| Grading or staging | Cancer is identified, but its aggressiveness or extent is understated. | A prostate biopsy is given too low a Gleason grade, so treatment is too conservative. |
The first two patterns concern the reader's judgement, and perceptual errors where a visible finding is not seen make up the larger share in radiology 3. The third can be a fault of technique rather than interpretation. The fourth changes the treatment a patient is offered. Each carries a different proof burden, which is why a careful early assessment matters.
One related failure sits at the edge of this topic. A radiologist who spots a critical, unexpected finding has a duty to communicate it directly and promptly, not only to file the report 4. Where a correct report was issued but never acted on, that is a different claim, explained on our separate page about test results that are not followed up.
The table below shows how a misread differs from the claims that sit beside it in Ireland.
| What happened | Failure type | Where it belongs |
|---|---|---|
| A scan or slide was read and reported as normal or benign when cancer was present. | Interpretive misread | This page |
| The biopsy did not capture the tumour, so the sample held no cancer to find. | Sampling failure | This page, with a different expert |
| A correct report was issued, but no one acted on it. | Follow-up failure | Test results not followed up |
| A GP did not refer or investigate clear red-flag symptoms. | Referral failure | Failure to refer |
Why this is a recognised basis for a claim
Irish courts treat a misread scan or biopsy as a recognised basis for a cancer negligence claim. The Supreme Court confirmed in Morrissey v HSE [2020] IESC 6 (March 2020) [1] that the standard for reading a diagnostic sample is the Dunne test.
Morrissey arose from cervical smears that were reported as negative and later found, on audit, to have been misread by laboratories the HSE had contracted abroad. The Court reaffirmed the test from Dunne v National Maternity Hospital [1989] IR 91. A reader is negligent where the reading falls below the standard that no competent practitioner of equal specialist status would fall below when acting with ordinary care 1. The Court also clarified that a screener's practical duty of confidence describes the medical task. It isn't a separate legal test. The HSE could not avoid responsibility by outsourcing the testing, because the duty was non-delegable.
This standard differs from the Bolam approach in England and Wales. Under the Dunne principles an Irish court can reject a defence expert's opinion where a practice has inherent defects that should be obvious on careful consideration. A defendant can't defend a clearly visible missed tumour simply by producing another reader who says they might have missed it too.
One point decides many of these cases. A misread isn't automatically negligent. Reading scans and slides involves judgement under uncertainty, and a baseline rate of discrepancy is unavoidable. An Irish review of radiology error puts the day-to-day discrepancy rate at roughly three to five per cent of reported studies. It confirms that a discrepancy doesn't equate to negligence Brady, Insights into Imaging (2017) [3]. The same theme runs through the national quality programmes for radiology and histopathology overseen by the relevant faculties Faculty of Radiologists, Quality Improvement (2024) [4]. A claim succeeds where the evidence shows the specific reading crossed the line into a breach.
Two Irish events show how seriously these failures are taken. The investigation into the care of Rebecca O'Malley found that a false-negative breast biopsy was the result of a once-off interpretive error by a locum consultant pathologist HIQA, Rebecca O'Malley Investigation (2008) [2]. Her diagnosis was then delayed and her prognosis fell. Separately, a review at University Hospital Kerry re-examined tens of thousands of images reported by a single overworked locum radiologist and identified patients whose cancer diagnosis had been delayed.
In the misread-sample cases we handle, the question is rarely whether a mistake happened. It is whether the mistake was one a careful specialist of the same standing would not have made.
↑ Back to topHow we prove breach of duty and causation
We prove a misread biopsy claim with an independent re-read. A consultant of equal specialist status reviews the original images or slides and shows the finding was there and should have been reported. A claim has two limbs, and both must be met.
The first limb is breach of duty. Beyond the re-read, we test the reading against the national quality standards the relevant faculties publish 4. Those standards cover synoptic reporting datasets, double-reading for certain screening, defined turnaround times, and mandatory review of complex cases at a multidisciplinary team meeting. For histopathology, the Faculty of Pathology sets measurable targets, including reporting 80 per cent of small biopsies within five days RCPI National Histopathology QI Programme (2024) [14]. It also asks laboratories to reconcile any discordance between a frozen-section diagnosis and the final report. A departure from those standards is strong evidence of breach. We also account for hindsight bias, because a finding can look obvious once the answer is known. The State Claims Agency makes the same point about missed cancers preserved on a scan, so we keep the re-read independent and, where possible, blind to the outcome 13.
The second limb is causation. The State Claims Agency, which defends most public-hospital claims in Ireland, often accepts that a misreading occurred and instead fights on whether it changed anything 6. We meet that by proving stage shift and loss of chance in cancer claims. Irish law treats the lost opportunity for earlier or less aggressive treatment as a compensable harm in its own right, following Philp v Ryan [2004] IESC 105 (December 2004) [5].
| Common defence argument | How we answer it |
|---|---|
| The finding was not really visible, given dense tissue or a difficult image. | Independent re-read and side-by-side comparison showing the finding was perceptible and reportable. |
| It was an honest difference of opinion between competent readers. | Evidence of a departure from the national reporting datasets and a failure to seek the required peer or MDT review. |
| The outcome would have been the same because the cancer was aggressive. | Stage-shift analysis and the loss-of-chance principle in Philp v Ryan. |
Early evidence preservation is the practical priority. We request the full records by data access request. We also ask the hospital to preserve the original slides, the paraffin blocks and the imaging files, so an independent expert can review the same material the original reader saw. Where imaging and pathology do not agree, that discordance is itself a prompt to re-review.
We move quickly to preserve the original slides and images, because the independent re-read is usually the point on which a misread-sample case turns.
↑ Back to topHow it links to your cancer type and outcome
How a misread scan or biopsy affects you depends on your cancer type and stage. The interpretive failure is the same, yet the harm it causes is shaped by tumour biology and by how far the cancer moved during the delay.
The mechanism repeats across cancers. A mammogram or a breast biopsy can be reported as clear, which is covered in detail on our breast cancer misdiagnosis page. A lung nodule can be missed on a chest scan, which our lung cancer misdiagnosis page addresses. A skin lesion can be misclassified, and a prostate or bowel biopsy can be under-graded. In each case the misread is the failure, while the cancer type decides the likely harm and the experts a claim needs.
The compensable gap is the stage shift. If a treatable, early cancer is allowed to grow because a scan or sample was read wrong, the patient can lose the chance of curative or less aggressive treatment. That lost chance is the heart of the claim, and it is why two cases with the same misreading can have very different value depending on what the delay cost.
Compensation and next steps
Compensation in a misread biopsy claim reflects the avoidable harm the delay caused. Every case is different and awards in Ireland vary on the facts, so we don't quote figures. We offer a free, confidential consultation to assess whether you have a claim.
A claim can take account of the lost treatment opportunity and any extra or more aggressive treatment the delay made necessary. It can also cover the pain, the impact on daily life, and financial losses such as care, equipment and lost earnings. Where a misdiagnosis has tragically proved fatal, dependants may bring a claim under the Civil Liability Act 1961 (1961) [10]. General damages in clinical negligence are assessed on the specific facts, with the Judicial Council Personal Injuries Guidelines (2021) [11] as the general reference point, and outcomes vary case by case.
The first practical step is to gather your medical records and seek advice early, because building this kind of case takes time. Most cancer negligence claims in Ireland are handled on a no-win, no-fee basis. That means you pay no solicitor fees unless compensation is recovered, subject to the standard terms explained at the outset. Clinical negligence claims proceed through the courts rather than the Injuries Resolution Board.
Steps to take if you think your scan or biopsy was misread
- Request your full medical records, including the images and the tissue slides.
- Ask the hospital in writing to preserve the original images, slides and blocks.
- Have an independent specialist of equal standing re-read the original material.
- Take legal advice within the time limit, which is usually two years from your date of knowledge.
Time limits
In Ireland you generally have two years to bring a misread biopsy claim. The two years usually run from your date of knowledge. That's often the day a later re-read or second opinion revealed the earlier error, not the day of the original result.
The two-year period and the date-of-knowledge rule come from the Statute of Limitations (Amendment) Act 1991 (1991) [7], as amended by the Civil Liability and Courts Act 2004 (2004) [15], which reduced the period from three years to two. For a misread sample, knowledge frequently arrives late, because the first report told the patient nothing was wrong. It can be triggered by a fresh diagnosis, a second opinion, or an audit. Mandatory open disclosure, brought in under the Patient Safety Act, can also be the moment a patient learns of an earlier error gov.ie, Patient Safety Act commencement (2024) [8].
There are limited exceptions. For a child, the period generally doesn't start until their eighteenth birthday, and time can be paused where a person lacks the capacity to manage their affairs. Because the exact start date turns on the facts, it's safest to take advice quickly. You can read more about how the clock works on our date of knowledge page.
↑ Back to topCommon questions
Is a misread scan or biopsy on its own enough to claim?
No. A misread on its own isn't enough to claim.
You must show two things. First, that the reading fell below the Dunne standard expected of a competent radiologist or pathologist 1. Second, that the delay caused avoidable harm, which is the question of causation. A genuine error within the accepted margin of judgement doesn't, by itself, found a claim.
In practice the dividing line is whether a careful specialist of equal standing would have made the same call on the same material.
A solicitor can arrange an independent review to test that question.
How do you prove the failure caused harm?
We prove harm by showing the misreading cost you treatment options, survival time, or both.
An independent re-read shows the finding was present and should have been reported. We then prove stage shift, showing the cancer advanced during the delay, and apply the loss-of-chance principle from Philp v Ryan [2004] IESC 105 5.
Causation, rather than the error itself, is where most Irish misread cases are won or lost.
Preserving the original slides and images early protects this evidence.
How do you prove a scan or biopsy was actually misread?
We prove a misread with an independent re-read of the original images or slides.
A consultant of equal specialist status reviews the same material the original reader saw and reports whether the finding was there. We compare that reading against the national reporting standards the faculties publish 4.
A re-read done blind to the later diagnosis carries more weight, because it controls for hindsight.
We request your records and ask the hospital to preserve the originals at the outset.
What records and evidence do I need?
You need the original images or slides, the pathology blocks, and your full medical records.
We obtain these through a data access request and a preservation letter to the hospital. The DICOM imaging files, the paraffin blocks and the reporting history all matter to an independent expert.
Slides and blocks can be discarded as retention periods expire, so timing affects what survives for review.
A solicitor can send the preservation request on your behalf without delay.
Is a misread always negligent?
No. A misread isn't always negligent.
Reading scans and slides involves judgement under uncertainty, and an Irish review puts the day-to-day discrepancy rate at roughly three to five per cent 3. A discrepancy becomes negligence only where it falls below the Dunne standard.
The defence often argues an honest difference of opinion, which we meet with the reporting standards and the peer-review record.
An independent expert opinion decides whether the threshold is crossed.
What is the time limit?
Generally two years from your date of knowledge.
The period comes from the Statute of Limitations (Amendment) Act 1991 7, as amended by the Civil Liability and Courts Act 2004 15, which cut it to two years. For a misread sample, that date often runs from a later re-read, second opinion or open-disclosure notification rather than the original result.
Because the start date turns on when you could reasonably have known, it's worth checking even if the first result was years ago.
Different rules apply for children and those who lack capacity, so take advice promptly.
What if the biopsy sample itself missed the cancer?
A sampling failure can still found a claim, but it's a different question from a misread.
If an inadequate biopsy never captured the malignant tissue, the slide genuinely contained no cancer. The question then is whether the sampling technique fell below the expected standard, not whether the pathologist misread the slide.
Telling a sampling error apart from an interpretive error changes which expert and which records matter.
An early review can identify which type of failure occurred in your case.
What should I do if I think my scan or biopsy was misread?
Gather your medical records and seek legal advice early.
Building a misread case takes time, and the original images and slides need to be preserved before they are lost. Most cancer negligence claims in Ireland are handled on a no-win, no-fee basis, subject to the standard terms explained at the outset.
A free, confidential consultation can tell you whether you have a claim worth pursuing.
What is the difference between a misread scan and a missed diagnosis?
A missed finding on a scan is a type of misread, but a missed diagnosis can also mean a test was never done or never acted on.
Where the cancer was visible on the image or slide and the reader did not report it, that is a perceptual misread, covered here. Where the diagnosis was missed because no test was ordered, or a correct report was not acted on, those are different claims.
Pinning down which failure occurred decides which page applies, and which expert a claim needs.
An early review of your records identifies the failure type.
Do I need a second opinion or re-read to claim?
Yes, in practice. An independent re-read is how a misread claim is proven.
A consultant of equal specialist status reviews the original images or slides to show the finding was there and should have been reported. You do not need to arrange this yourself before contacting a solicitor.
The re-read should be blind to the later diagnosis where possible, to control for hindsight.
A solicitor arranges the independent review as part of investigating the claim.
This information is for educational purposes only and does not constitute legal advice. Every case is different and outcomes vary. Consult a qualified solicitor for advice specific to your situation. Reviewed by Gary Matthews, Solicitor, Law Society of Ireland Practising Certificate No. S8178. Last reviewed .
References
All external sources were last accessed in June 2026. Legislation links resolve to the electronic Irish Statute Book.
- Morrissey v Health Service Executive [2020] IESC 6, Supreme Court (March 2020). Reaffirms the Dunne v National Maternity Hospital [1989] IR 91 standard and the non-delegable duty.
- HIQA, Investigation into the care received by Rebecca O'Malley (2008).
- Brady AP, Error and discrepancy in radiology: inevitable or avoidable?, Insights into Imaging (2017).
- Faculty of Radiologists and Radiation Oncologists, RCSI, Quality Improvement Programme (2024), with the National Histopathology Quality Improvement Programme, RCPI.
- Philp v Ryan [2004] IESC 105, Supreme Court (December 2004). Loss of chance as a recognised head of damage.
- State Claims Agency, NTMA Annual Report 2024 (published July 2025). Clinical claims volume, liability and mediation data.
- Statute of Limitations (Amendment) Act 1991, section 3 (two-year limitation period), with date of knowledge defined at section 2.
- gov.ie, Commencement of the Patient Safety (Notifiable Incidents and Open Disclosure) Act 2023 (2024).
- National Cancer Registry Ireland, cancer incidence statistics (2024).
- Civil Liability Act 1961, section 48 (action for the benefit of dependants in fatal cases).
- Judicial Council, Personal Injuries Guidelines (2021).
- Citizens Information, Taking and appealing a civil case (2025). Personal-injury time limits.
- State Claims Agency, Learning from Radiology Claims (October 2023). Diagnostic-error and missed-diagnosis breakdown.
- RCPI, National Histopathology Quality Improvement Programme (2024). Histopathology key quality indicators and turnaround targets.
- Civil Liability and Courts Act 2004, section 7 (reduced the personal-injuries limitation period to two years, effective 31 March 2005).
Related reading on this site: cancer misdiagnosis claims in Ireland, radiology misdiagnosis claims, and pathology and laboratory error claims.
This page is general legal information about the law in Ireland, not legal advice. Outcomes vary on the facts of each case.
Gary Matthews Solicitors
Medical negligence solicitors, Dublin
We help people every day of the week (weekends and bank holidays included) that have either been injured or harmed as a result of an accident or have suffered from negligence or malpractice.
Contact us at our Dublin office to get started with your claim today
