Pathology and Laboratory Error Claims in Ireland: When the Lab Test Itself is Negligent

Gary Matthews, Medical Negligence Solicitor Dublin

Author: Gary Matthews, Principal Solicitor, Law Society of Ireland PC No. S8178 • 3rd Floor, Ormond Building, 31–36 Ormond Quay Upper, Dublin D07 • 01 903 6408

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A pathology and laboratory error claim in Ireland is a specialised medical negligence action brought when a testing facility, pathologist, or laboratory technician produces a flawed result that causes avoidable harm. This is not the same as a doctor failing to act on a correct result. The error happens inside the laboratory itself, through slide misreads, sample contamination, mislabelling, staining failures, or equipment calibration problems.

Irish laboratories must comply with ISO 15189:2022 accreditation standards (INAB)1, and a breach of those standards is admissible as direct evidence of substandard care. The Supreme Court confirmed in Morrissey v HSE [2020] IESC 62 that the HSE retains a non-delegable duty of care even when testing is outsourced to a private laboratory. This is general information, not legal advice. Every case turns on its own facts and outcomes vary. Consult a solicitor for advice specific to your situation.

Lab-internal errors (slide misreads, sample mix-ups, staining failures) create a separate claim pathway from general misdiagnosis. Prove breach through a blinded independent pathology review. Two-year time limit from date of knowledge. Clinical negligence claims bypass the IRB entirely. Private labs can be sued directly. Sources: INAB1Morrissey v HSE [2020] IESC 62.

Contents
Legal test: Dunne principles (not the UK's Bolam test). Would no competent pathologist of equal status have made this error?
Time limit: Two years from date of knowledge. The clock does not pause for expert reports. Time limits guide
IRB exemption: Clinical negligence claims bypass the Injuries Resolution Board entirely under s.3(d) of the PIAB Act 20033.
Private lab liability: According to RTÉ Business (November 2025)4, Medlab Pathology Ltd paid €26.86m in settlements and legal costs in a single year (2023).

Just discovered a possible lab error? Act within 48 hours.

  1. Contact a medical negligence solicitor immediately. The two-year clock may already be running from the date you learned the earlier result was wrong.
  2. Send a preservation letter to the laboratory requesting that all original slides, paraffin tissue blocks, and LIMS processing records be preserved and not destroyed.
  3. Submit a DSAR under GDPR specifically naming the laboratory's own data systems, not just the hospital chart. See our records request guide for the exact wording.
Diagnostic Chain of Custody: specimen collection to clinician receipt, left to right Specimen collected Patient / phlebotomist Lab processes sample Technician / equipment Pathologist interprets Slide / result analysis Result dispatched Healthlink / phone Clinician receives
The Diagnostic Chain of Custody. This page covers errors in the shaded green and blue stages (lab processing and pathologist interpretation). Errors after dispatch are covered in our test results not followed up guide.

What counts as a laboratory error (and what doesn't)?

A laboratory error occurs when the testing facility itself produces an incorrect, contaminated, or lost result, and that failure causes avoidable harm to the patient. The liability sits with the pathologist, laboratory technician, or testing facility rather than with the treating doctor. According to the Dunne principles established in Dunne v National Maternity Hospital [1989] IR 91, Irish courts assess whether no competent pathologist of equal specialist status would have made the same error when exercising ordinary care. Unlike in England and Wales, where the Bolam test applies, Ireland uses this distinctly higher threshold.

A detail that catches many claimants off guard: an honest difference of opinion between two competent pathologists about a complex cellular anomaly does not automatically amount to negligence. Pathology involves genuine interpretive judgment, particularly when grading borderline tissue samples. The claim succeeds when the error falls below the floor of acceptable professional competence, not simply because two experts disagree.

This page does not cover scenarios where a laboratory produces a correct result but the treating doctor fails to read, open, or act on it. Those claims involve administrative communication failures with a different liability profile. It also doesn't cover the disease-specific impacts of delayed cancer diagnosis, which are addressed in our cancer misdiagnosis guide.

How lab errors actually happen

Laboratory errors in Ireland fall into distinct categories, each creating a different evidence trail and requiring a specific type of independent expert review. According to the INAB accreditation framework (2022)1, laboratories must maintain documented quality systems across every stage of testing. Understanding the technical mechanism matters because it determines which records your solicitor must request and which expert must examine them.

Interpretive errors

A consultant pathologist examines a tissue sample under a microscope and misclassifies what they see. Common examples include undergrading a biopsy (calling a malignant cell cluster benign), confusing reactive tissue changes with genuine pathology, or failing to request additional immunohistochemistry staining when the initial slide is ambiguous. The CervicalCheck audit ultimately identified 221 women who had received false-negative cervical smear results, many of which involved interpretive failures at the slide-reading stage2.

Processing and handling errors

These occur before the pathologist ever sees the sample. They include mislabelling specimen vials (attaching one patient's name to another patient's tissue), cross-contaminating paraffin blocks during sectioning, using expired reagents for staining, and calibration failures in automated analysers such as centrifuges or haematology platforms. Processing errors are often traceable through the laboratory's internal quality control records and equipment calibration logs.

Pre-analytical errors

Some errors happen even earlier in the Diagnostic Chain of Custody, before the sample reaches the laboratory bench. These pre-analytical failures include using the wrong collection tube (affecting how the sample is preserved), delayed transport causing the specimen to degrade, or inadequate patient identification at the point of collection. Under ISO 15189, laboratories have a duty to assess incoming specimens and reject those that are inadequate for testing. A lab that processes a visibly haemolysed or degraded sample without flagging the limitation, and then issues a report based on that material, has failed at the pre-analytical quality gate.

Which types of tests carry the highest error risk?

Error mechanisms differ across laboratory disciplines, and the type of test determines which expert your solicitor needs to instruct. The main areas where lab errors generate claims in Ireland include histopathology (biopsy and surgical tissue slides, where interpretation is inherently subjective), cytology (cervical smears, fine needle aspirates, and fluid specimens), haematology (full blood count analysis, clotting studies), biochemistry (liver function, kidney function, tumour markers such as PSA or CA-125), and microbiology (bacterial cultures and antibiotic sensitivity testing). Histopathology and cytology claims typically require a blinded slide review, while biochemistry and haematology claims often turn on equipment calibration records and internal quality control data.

Transcription and dispatch errors

The pathologist analyses the sample correctly, but the result entered into the Laboratory Information Management System (LIMS) contains a data-entry mistake, such as transposing digits in a tumour grading or attaching the report to the wrong patient record. Under HSE laboratory protocols (HSE Pathology, December 2025)11, critical results are classified into three categories with mandatory communication timelines. Category A results (potential immediate danger to the patient) must be communicated within two hours. Category B results (urgent but not immediately life-threatening) require communication within 24 hours, preferably the same working day. Category C results have an immediate impact on patient management. Relying solely on routine electronic dispatch via Healthlink for a Category A result, rather than telephoning the requesting clinician within two hours, is itself a provable breach of mandatory safety protocols.

HSE critical result categories: mandatory laboratory communication timelines Category A Immediate danger to patient e.g. critical potassium, severe sepsis markers Telephone within 2 hours Healthlink alone = breach Category B Urgent, not immediately life-threatening e.g. significant abnormal pathology findings Within 24 hours (same day) Category C Immediate impact on patient management e.g. results requiring change in treatment plan Same working day
HSE mandatory communication timelines for critical laboratory results. A laboratory that fails to follow these protocols has provable evidence of substandard practice. Source: HSE National Laboratory Handbook11.

Who is liable when a lab gets it wrong?

The liable party depends on where the test was performed and who ordered it. According to the Supreme Court in Morrissey v HSE [2020] IESC 62, the HSE retains liability even when testing is outsourced to a private contractor. Irish law creates multiple routes to hold testing facilities accountable.

Who is liable for a laboratory error? Three pathways based on where testing occurred Where was the test performed? Public hospital lab Defendant: HSE Managed by: State Claims Agency Scheme: Clinical Indemnity Scheme Lab staff covered as HSE employees Outsourced private lab Defendants: HSE + private lab HSE: non-delegable duty (Morrissey) Private lab: own insurer pays Both can be sued simultaneously Private hospital lab Defendant: private hospital Not covered by CIS Hospital's own indemnity insurer e.g. Beacon, Blackrock, Mater Private
Your solicitor identifies the correct defendant based on where the test was processed. In outsourced cases, both the HSE and the private laboratory can face claims simultaneously under the Morrissey ruling2.

Public hospital laboratories

The HSE is the defendant for errors in its own hospital laboratories. The State Claims Agency (SCA) [5] manages these claims under the Clinical Indemnity Scheme. According to the SCA's 2024 data reported in the NTMA 2024 Annual Report (RTÉ, July 2025) [6], outstanding clinical negligence liabilities reached €5.35 billion across 10,968 active claims. Laboratory technicians, phlebotomists, and hospital-employed pathologists are all covered under the Scheme.

Outsourced and private laboratories

The Supreme Court's ruling in Morrissey v HSE [2020] IESC 6 confirmed that the HSE holds a non-delegable duty of care to patients, even when screening or testing is outsourced to a private laboratory2. In practice, this means both the HSE and the private lab can face claims. Medlab Pathology Ltd, a Dublin-based private laboratory involved in the CervicalCheck programme, paid €26.86 million in settlements and legal costs in the 12 months to June 2023 alone, according to company accounts signed in October 20254. The company had set aside a gross provision of €49.6 million to deal with the full cost of CervicalCheck-related High Court actions.

One aspect the official guidance doesn't cover: the SCA itself paid only €710,000 in CervicalCheck-related damages by mid-2023. The overwhelming majority of payouts came directly from the private laboratory's own insurance and reserves. This confirms that private labs in Ireland carry real financial exposure and can be held directly accountable.

Private hospital laboratories

The Clinical Indemnity Scheme does not cover private hospitals such as the Beacon, Blackrock Clinic, or Mater Private. Claims against private hospital labs go to the hospital's own professional indemnity insurer. Your solicitor identifies the correct defendant based on where the test was processed, not where the sample was collected.

How to prove a laboratory error in Ireland

Proving a lab error requires obtaining the original physical specimens and laboratory processing records, then commissioning an independent blinded review by a consultant pathologist of equal specialist standing. According to the Dunne principles (Dunne v National Maternity Hospital [1989] IR 91), the reviewing expert must demonstrate that no competent pathologist of equal status would have made the same error. A generic request for "medical records" will not produce the laboratory-specific evidence needed to establish breach.

  1. Secure your laboratory records specifically. Your solicitor should submit a targeted Data Subject Access Request (DSAR) under GDPR that explicitly names the LIMS records, original pathology slides or preserved tissue blocks, equipment calibration logs, and Healthlink dispatch records. Standard hospital chart requests typically do not capture this data. See our medical records request guide for the full process.
  2. Preserve the physical specimens. HSE policy requires paraffin blocks to be retained for a minimum of ten years. These blocks allow an independent pathologist to cut new sections and re-examine the tissue under a microscope. The timing matters more than most guides suggest: act quickly, because private labs are not bound by identical retention periods.
  3. Commission a blinded independent review. The reviewing pathologist examines the original slides or newly cut sections without knowing the original report's conclusion. This removes confirmation bias and produces a genuinely independent assessment. The expert must hold qualifications and standing equivalent to the pathologist being criticised, as required for any expert medical report in Irish clinical negligence proceedings.
Blinded review process: three steps from slides received to findings compared 1. Slides received blind Expert receives slides WITHOUT seeing the original lab report 2. Independent examination Consultant pathologist examines tissue and records own findings 3. Findings compared Independent findings measured against original report Removes confirmation bias. Courts give this significantly more weight than a standard second opinion.
The blinded review removes confirmation bias. The expert forms their own conclusion before ever seeing what the original pathologist reported.

Common mistake: Requesting a "second opinion" where the reviewing pathologist reads the original report first. This isn't a blinded review. Courts give significantly more weight to an expert who examined the tissue independently and reached their own conclusion before seeing the original report.

Quality assurance failures as independent evidence of breach

ISO 15189 requires every accredited laboratory to operate two quality safety nets. Internal Quality Control (IQC) involves running known reference samples alongside patient specimens each day to verify that equipment and reagents are performing correctly. External Quality Assessment (EQA), also called proficiency testing, is a separate process where an external body such as UK NEQAS sends blind unknown samples to participating laboratories, and results are compared nationally. A lab that failed its EQA proficiency testing around the date of your test, or that skipped IQC runs on the relevant analyser, has independent, documented evidence of systemic substandard practice. This evidence exists separately from the blinded review and can significantly strengthen the breach element of a claim. Your solicitor should specifically request the laboratory's IQC and EQA records for the relevant period as part of the DSAR.

The causation challenge in lab error claims

Proving that a laboratory made a mistake is only the first step. The second, and often more contested, hurdle is proving that the mistake actually caused your harm. This is the causation element of the claim. According to State Claims Agency data for 2024 (RTÉ, July 2025)6, only about 2% of clinical claims reach a court judgment, which means the vast majority are resolved through negotiation or mediation where causation is the central battleground.

The SCA frequently accepts that a breach occurred at the laboratory level but argues the causation element fails. The standard defence relies on expert testimony arguing that the disease, such as an aggressive carcinoma, had already progressed beyond curative intervention by the time the original misread test was taken. The defence position is that the lab error, while regrettable, made no material difference to the patient's ultimate outcome.

To counter this defence, your legal team needs an interlocking matrix of expert reports. A pathology expert proves the lab made the analytical error. A separate specialist, typically an oncologist or the relevant clinical expert, proves that an earlier correct result would have altered the treatment pathway or statistically improved survival probability on the balance of probabilities. This can involve complex clinical modelling, including tumour doubling-time calculations, to demonstrate precisely how the delay caused by the lab error allowed the condition to progress from a treatable stage to a more advanced one.

Between assessment and settlement, the sticking point is usually causation rather than breach. Labs and the SCA rarely deny the analytical mistake outright when the blinded review is compelling. The dispute almost always centres on whether earlier detection would have changed the outcome.

There is, however, a second common defence strategy: the defendant laboratory hires its own consultant pathologist, who reviews the same slides and testifies that the original reading fell within the range of acceptable professional judgment. This "honest difference of opinion" defence is strongest in borderline cases, where tissue shows ambiguous cellular changes that competent pathologists could reasonably classify differently. It fails in clear-cut cases, such as a biopsy containing obvious malignant cells that were reported as benign. The distinction matters for your solicitor's case assessment: a claim based on a genuinely grey-zone interpretation is harder to prove than one where the blinded review reveals an error no competent pathologist would have made. Experienced solicitors assess this boundary before advising you to proceed.

How a lab error claim typically unfolds (anonymised example): A patient has a biopsy taken in a public hospital. The pathologist reports the tissue as benign. Two years later, persistent symptoms lead to a repeat biopsy at a different facility, which reveals an advanced malignancy. The patient's solicitor issues a preservation letter to the original laboratory and submits a targeted DSAR for the LIMS records, original slides, and paraffin blocks. An independent consultant pathologist performs a blinded review of the original slides and confirms the first reading missed clear abnormal cells. A separate oncology expert then calculates the tumour doubling time and demonstrates that the cancer was at a treatable stage when the first biopsy was taken. The claim settles through mediation with both the HSE (under its non-delegable duty) and the laboratory's insurer contributing to the award.

Time limits and the date of knowledge rule

The limitation period for a pathology error claim in Ireland is two years from the date of knowledge. According to the Statute of Limitations (Amendment) Act 19917, the clock begins when you possess four interlocking pieces of information: you recognise you've suffered a significant injury, you understand the injury is attributable to a specific medical act or omission, you identify the responsible provider or laboratory, and you have sufficient foundational facts to investigate the negligence.

Lab error claims create a particular risk because the original error may remain hidden for years. You receive a "normal" test result, and only when symptoms persist or a second test years later reveals advanced disease does the earlier failure become apparent. The date of knowledge is typically the date of your correct diagnosis, or the date you're told the earlier result was wrong. Unlike in England and Wales, where the limitation period is three years, Irish law allows only two years from this date. That one-year difference catches people who read UK guidance and assume they have more time than they actually do.

The clock does not pause while you wait for an independent expert report to confirm the lab's mistake. Under Irish case law, the limitation period runs from when you have sufficient foundational facts to begin investigating, not from when a medical expert formally confirms the negligence. Under the Patient Safety (Notifiable Incidents and Open Disclosure) Act 20238 (Parts 1 to 4 commenced 26 September 2024), a formal open disclosure meeting about a testing error may crystallise your date of knowledge and start the two-year countdown immediately.

Clinical negligence claims, including lab error claims, are entirely exempt from the Injuries Resolution Board process under s.3(d) of the PIAB Act 20033. You don't apply to the IRB. The claim proceeds directly to the High Court. For children, the two-year clock doesn't start until their 18th birthday. See our date of knowledge and time limits guides for the full rules.

What evidence to request in your DSAR

Standard hospital records requests produce discharge summaries and outpatient letters, which are insufficient for investigating a lab-internal error. According to the Data Protection Commission (DPC)13, you have a right of access under GDPR to all personal data held about you, including data held in laboratory systems separate from the main hospital chart. Your solicitor's DSAR must specifically target the laboratory's own data systems at each stage of the Diagnostic Chain of Custody, from specimen reception through analysis, interpretation, and electronic dispatch.

Specific records to request in a suspected laboratory error claim
Record typeWhat it revealsWhere it's held
LIMS processing recordsTimestamps, analyst identity, quality control flags, batch numbersLaboratory Information Management System (separate from hospital chart)
Original pathology slidesThe physical tissue sections the pathologist examinedLaboratory slide archive
Paraffin tissue blocksPreserved tissue for re-cutting and independent re-examination (retained minimum 10 years under HSE policy)Laboratory tissue store
Equipment calibration logsWhether analysers and staining equipment were within specification on the relevant dateLaboratory quality management system
Healthlink dispatch logsWhen and how the result was transmitted to the requesting clinicianHealthlink electronic messaging system
IQC and EQA recordsInternal Quality Control daily run data and External Quality Assessment (proficiency testing) results for the relevant analyser and periodLaboratory quality management system

What if your case involves additional complexity?

The process above covers straightforward lab error claims where a single laboratory produced a single flawed result. Some cases, however, involve layers of complexity that affect both the strategy and the timeline.

If testing was outsourced, your solicitor must identify whether the laboratory operated as an agent of the HSE (engaging the non-delegable duty from Morrissey) or as an independent private provider with its own insurance. ISO 15189 accreditation status matters here. The INAB directory of accredited medical testing laboratories9 lists every laboratory operating under the standard in Ireland, along with their scope of accreditation. A laboratory that was not accredited at the time of the error faces a particularly difficult defence, because ISO 15189 compliance is the recognised benchmark for quality and competence in Irish medical testing.

Cases involving national screening programmes (CervicalCheck, BreastCheck, BowelScreen) add a further dimension. Part 5 of the Patient Safety Act 2023 creates a right for patients to request a review of their screening results, but this provision has not yet commenced as of March 20268. Affected patients currently need to pursue court proceedings for actual compensation.

Can you complain about a pathologist as well as claim?

A complaint to the Medical Council (Guide to Professional Conduct and Ethics, 9th Edition 2024)12 runs on a completely separate track from a civil compensation claim. Filing a complaint does not replace or substitute for a claim, and bringing a claim does not require you to have complained first. The complaint process investigates whether the pathologist met the Council's professional standards. The civil claim investigates whether the laboratory's failure caused you compensable harm. Medical scientists (laboratory technicians) are registered with CORU rather than the Medical Council, so a processing error by a technician would involve a different regulatory body. Your solicitor can advise on whether pursuing both routes is appropriate for your circumstances.

Check a laboratory's accreditation yourself. The INAB directory9 is publicly accessible. Search for the laboratory that processed your test and check whether it held current ISO 15189 accreditation at the time of your test. A laboratory that was unaccredited, or that had its accreditation suspended or withdrawn around the relevant period, faces a considerably stronger claim against it. Your solicitor can use the accreditation schedule to identify exactly which tests the laboratory was and was not accredited to perform.

What about false positive results?

Most of this page focuses on false-negative errors, where the lab misses something that should have been found. False-positive errors work in the opposite direction: the laboratory reports a condition that does not exist. A patient told they have cancer based on a misread biopsy may undergo surgery, chemotherapy, or radiation that was never medically necessary. The causation proof is different from a false-negative claim. You prove that you would not have undergone those procedures, and would not have suffered the associated physical and psychological harm, with a correct laboratory result. The unnecessary treatment itself is the compensable harm. These claims can involve substantial general damages for the psychological trauma of living under a false cancer diagnosis, undergoing invasive treatment, and then discovering it was avoidable.

How compensation works in lab error claims

According to the Personal Injuries Guidelines (Judicial Council, 2021)10, compensation in a successful lab error claim is assessed under the same framework that applies to all clinical negligence claims in Ireland. Awards are divided into two categories.

General damages compensate for pain, suffering, and the psychological impact of the error. Lab errors involving false-negative cancer results frequently involve severe anxiety, post-traumatic stress, and the trauma of learning that a treatable condition has become advanced. The Guidelines set out specific bands based on injury severity, duration, and prognosis. Special damages cover quantifiable financial losses directly caused by the error, such as additional medical treatment, private consultations, travel costs, loss of earnings, and future care needs. In catastrophic cases where delayed diagnosis leads to permanent disability, special damages can include the cost of home adaptations and lifelong support. See our compensation guide for the detailed breakdown.

The SCA resolves approximately 43% of clinical claims through mediation, according to its 2024 data6. Only about 2% of resolved claims reach a court judgment. Lab error claims tend to sit at the longer end of the timeline because causation disputes require multiple expert reports from different specialities.

What most guides miss about lab error claims

Every other Irish solicitor page treats laboratory errors as a subset of general misdiagnosis. That approach misses five things that can determine whether a claim succeeds or fails.

  1. The lab has its own quality records. LIMS processing data, IQC daily calibration runs, and EQA proficiency testing results exist separately from the hospital chart. A generic medical records request will not capture them. Your solicitor must name these systems specifically in the DSAR.
  2. A blinded review is not the same as a second opinion. An expert who reads the original report before examining the slides is subject to confirmation bias. Courts give significantly less weight to a review that was not conducted blind.
  3. Private labs carry real financial exposure. Medlab Pathology Ltd paid €26.86 million in a single year from its own insurance. The SCA paid only €710,000 in the same period. Knowing who actually pays matters for settlement strategy.
  4. ISO 15189 accreditation breaches create objective evidence. Unlike subjective disputes about clinical judgment, a laboratory that failed its proficiency testing or operated without current accreditation has measurable, documented evidence of substandard practice.
  5. The physical specimens must be preserved immediately. Paraffin blocks and original slides can be destroyed after retention periods expire. Private labs are not bound by the same ten-year HSE retention policy. A preservation letter sent within the first 48 hours protects the most critical evidence.

How lab error claims differ from other diagnostic failures

Where the error happened determines the claim pathway
Claim typeWhere the error occursWho is liableKey evidence
Pathology / lab error (this page)Inside the laboratory: slide misread, sample mix-up, staining failure, equipment faultPathologist, lab technician, testing facility, ISO 15189 accreditation breachLIMS records, original slides, paraffin blocks, blinded independent review
Test results not followed upAfter the lab correctly generates a result: the clinician does not open, read, or act on itGP, hospital consultant, practice management software failureHealthlink logs, GP management system records, patient recall records
General misdiagnosisAt the clinical assessment stage: the doctor fails to piece together symptoms, history, and testsThe treating clinician failing to meet the Dunne standard during examinationClinical notes, symptom timeline, referral records, expert clinical opinion
Cancer misdiagnosisThe disease-outcome level: cancer not detected in time, affecting staging and survivalOncologist, GP referral failure, NCCP Rapid Access Clinic targetsTNM staging progression, tumour doubling-time modelling, NCCP referral guidelines

Was the error in the lab or somewhere else?

Common Questions

What is a pathology error claim?

A pathology error claim is a medical negligence action in Ireland brought when a laboratory's analytical mistake, such as misreading a biopsy slide or mixing up blood samples, causes avoidable harm to a patient.

  • The error happens inside the lab, not at the clinical consultation stage.
  • The Dunne principles set the legal test for breach of duty.
  • ISO 15189 accreditation breach is admissible as evidence of substandard care.

Why it matters: Lab errors create a distinct claim pathway with different evidence requirements from general misdiagnosis claims.

Read more: Expert medical report guide

Can you sue a laboratory directly in Ireland?

Yes. Private laboratories can be sued directly in the High Court. Medlab Pathology Ltd paid €26.86 million in CervicalCheck-related settlements in 2023 alone.

The HSE is also liable under its non-delegable duty (Morrissey ruling). Private hospital labs face claims through their own insurers. Your solicitor identifies the correct defendant based on where testing occurred.

The key point: Many people assume you can only sue the hospital or HSE. Private labs carry real financial exposure.

See also: Causation guide

How do you prove a lab made a mistake?

Through a blinded independent review: an expert pathologist of equal standing examines the original slides or tissue blocks without knowing the original report's conclusion.

  • Request LIMS records and physical specimens through a targeted DSAR.
  • The reviewing expert must hold equivalent specialist qualifications.
  • A "second opinion" that reads the original report first isn't the same as a blinded review.

In practice: Courts give significantly more weight to genuinely independent, blinded assessments.

Next step: Medical records request guide

What is ISO 15189 and why does it matter for lab claims?

ISO 15189:2022 is the international standard for quality and competence in medical laboratories. In Ireland, the Irish National Accreditation Board (INAB) accredits labs to this standard.

  • A lab that breaches its accreditation requirements has objective evidence of substandard practice.
  • All Irish labs were required to transition to the 2022 edition by 20 August 2025 under INAB's transition plan.
  • Blood bank laboratories have been required to operate to ISO 15189 since 2008 under S.I. 360 of 2005.

Why it matters: Unlike subjective clinical judgment disputes, accreditation breaches provide measurable, documented evidence of failure.

Related: INAB accreditation (official)

How long do I have to make a lab error claim?

Two years from the date of knowledge under Irish law. The date of knowledge is typically the date you discover the earlier result was wrong, not the date the original test was performed.

The clock runs continuously and doesn't pause for expert reports. Clinical negligence claims bypass the IRB entirely. An open disclosure meeting about a testing error may crystallise your date of knowledge.

Worth knowing: Delayed discovery is common in lab error cases. You may have years between the original test and learning it was wrong.

Read more: Date of knowledge guide

Is the HSE liable if a private lab made the error?

Yes. The Supreme Court in Morrissey v HSE [2020] IESC 6 confirmed that the HSE has a non-delegable duty of care to patients. Outsourcing testing to a private laboratory does not shift liability.

  • Both the HSE and the private lab can face claims simultaneously.
  • The private lab's own insurer handles its portion of the claim.
  • The SCA manages the HSE's portion under the Clinical Indemnity Scheme.

Why it matters: Patients don't need to choose between suing the HSE or the lab. Both can be held accountable.

What are paraffin blocks and why do they matter?

Paraffin blocks are wax-embedded tissue samples preserved after a biopsy or surgical procedure. They allow new sections to be cut and re-examined years after the original test.

  • HSE policy requires retention for a minimum of ten years.
  • Private labs may apply different retention periods.
  • Your solicitor should send a preservation letter immediately to prevent destruction.

The key point: Without the original tissue, an independent pathologist cannot perform a blinded review. Securing these specimens early is critical.

Next step: How to request records

Does this apply to national screening programme errors?

Yes. CervicalCheck, BreastCheck, and BowelScreen all involve laboratory analysis. The Morrissey ruling arose directly from CervicalCheck, confirming the legal framework for screening-related lab claims.

  • Part 5 of the Patient Safety Act 2023 (screening review right) has not yet commenced.
  • Affected patients currently pursue court proceedings for compensation.
  • 385 CervicalCheck claims were received by the SCA, with 183 still active as of mid-2023.
  • The CervicalCheck Tribunal provides a separate resolution pathway for eligible claimants.

In practice: Screening errors follow the same legal principles, with the additional support of the non-delegable duty doctrine.

Related: Cancer misdiagnosis guide

Next in this series

Cancer Misdiagnosis Claims Ireland: Proving Delayed Diagnosis Changed Your Outcome

Test Results Not Followed Up: When the Lab Got It Right But Your Doctor Didn't Act

How to Request Medical Records in Ireland: A Targeted DSAR for Clinical Negligence Claims

References

[1] INAB, Accreditation of Medical Testing (ISO 15189:2022)

[2] Morrissey v HSE [2020] IESC 6 (Supreme Court)

[3] PIAB Act 2003, s.3(d) (Irish Statute Book)

[4] RTÉ Business, "Private lab firm pays out €26.86m" (November 2025)

[5] State Claims Agency (official)

[6] NTMA 2024 Annual Report, SCA section (RTÉ, July 2025)

[7] Statute of Limitations (Amendment) Act 1991 (Revised Acts)

[8] Patient Safety (Notifiable Incidents and Open Disclosure) Act 2023

[9] INAB Directory of Medical Testing Laboratories

[10] Personal Injuries Guidelines (Judicial Council, 2021)

[11] HSE Pathology Department, Laboratory User Manual (December 2025), implementing National Laboratory Handbook critical result protocols

[12] Medical Council, Guide to Professional Conduct and Ethics, 9th Edition (2024)

[13] Data Protection Commission, Rights of Individuals Under GDPR

Related guides on this site

Medical negligence in Ireland (pillar guide)

Misdiagnosis claims Ireland

Cancer misdiagnosis claims

Test results not followed up

Expert medical report

How to request medical records

Causation in medical negligence

Date of knowledge

Time limits

Compensation guide

*In contentious business, a solicitor may not calculate fees or other charges as a percentage or proportion of any award or settlement. This statement is made in compliance with Reg. 8 of S.I. 518 of 2002.

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