1800 202 8726
Quality & second opinions

Errors in Pathology: — How Often They Happen and What Stops Them

Worrying that a diagnosis could be wrong is one of the most common fears a patient or family describes. Pathology errors do occur — but knowing what kinds exist, how often they happen, and what safeguards are built into the process gives you something to act on rather than just something to fear.

Medically reviewed by Dr. Mohammed Imaduddin, Surgical Oncologist, MBBS · MS (General Surgery) · M.Ch (Surgical Oncology) · Last reviewed September 2026

  • Errors are tracked openly — The College of American Pathologists and the Royal College of Pathologists run quality programmes specifically to study and reduce discordance.
  • Not all errors are equal — Minor discordances are more common than major ones. A major error is where the diagnosis changes enough to alter your treatment.
  • Quality checks are layered — Accredited laboratories build in peer review, internal consultation, and multidisciplinary team discussion before treatment is planned.
  • A second opinion is a legitimate option — Requesting a review of your slides is a standard quality step — not a challenge to your pathologist, and not unusual to ask for.
4.8 · 800+ Google reviews · 15,000+ patients treated
Limited Slots Today

Get this explained properly

₹950   Today: FREE  ·  Including free written second opinion

Reply within 2 working hours
Report reviewed by a senior oncologist
Confidential. No commitment to start treatment.
or
Call 1800 202 8726
17+
Cancer Specialists
on Panel
96.9%
Breast Cancer
Survival Rate*
15,000+
Patients
Treated
4.8★
Google Rating
(800+ reviews)

Pathology errors are real and are tracked openly by the College of American Pathologists and the Royal College of Pathologists. Minor discordances between two pathologists reviewing the same case are more common than major ones — where a diagnosis changes enough to alter treatment. Most laboratories use layered quality checks to catch problems before a report reaches you.

How common are pathology errors?

Pathology errors exist and are tracked openly by quality programmes run by the College of American Pathologists and the Royal College of Pathologists. That tracking is what allows the question to be answered honestly.

The answer depends on how 'error' is defined. A minor discordance — where two pathologists looking at the same slide reach slightly different conclusions about grade or margin detail — is more common than a major discordance. A major discordance is where the diagnosis is different enough that the treatment you would receive changes.

The rate is also higher for some diagnoses than others. Lymphomas, soft tissue tumours, and rare cancer types involve genuine classification uncertainty, and even subspecialty pathologists acknowledge this. A discordant second opinion in these areas is not necessarily evidence that someone made a mistake.

What kinds of errors occur in pathology?

  • Sampling errorThe biopsy did not include the abnormal cells. The sample was uninformative from the start, not misread.
  • Processing errorTissue was handled or stored in a way that damaged it or made it harder to interpret clearly.
  • Interpretation errorThe pathologist read the slide differently from what it shows. This is what most people mean by misdiagnosis.
  • Grading errorThe tumour was given the wrong grade, which affects decisions about how intensively to treat.
  • Transcription errorA correct interpretation was recorded incorrectly in the written report — a clerical rather than a clinical failure.
  • Labelling errorThe wrong patient's sample is linked to the wrong name. Very rare and usually caught by internal identity checks.

Still unclear?

Send your reports across and a specialist will walk you through what they mean — what is known, what is not, and what the options actually are.

Meet the Specialists

17+ senior cancer specialists. One panel for your case.

Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.

Dr. Naresh Gundu
Medical Oncologist

Dr. Naresh Gundu

MBBS, DNB (Internal Medicine), DM (Medical Oncology)

View Profile
Dr. C. Raghavendra Reddy
Medical Oncologist

Dr. C. Raghavendra Reddy

MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)

View Profile
Dr. Bharati Devi Gorantla
Medical Oncologist

Dr. Bharati Devi Gorantla

MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)

View Profile
Dr. Owais Mohammed
Medical Oncologist

Dr. Owais Mohammed

MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)

View Profile
Dr. T. Raghavender Reddy
Medical Oncologist

Dr. T. Raghavender Reddy

MBBS, DM (Medical Oncology), MD (Radiation Oncology)

View Profile
Dr. N. Kiranmayee
Medical Oncologist

Dr. N. Kiranmayee

MBBS, DM (Medical Oncology), MD (Internal Medicine)

View Profile
Dr. Muralidhar Muddusetty
Surgical Oncologist

Dr. Muralidhar Muddusetty

MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)

View Profile
Dr. Raghavendra Naik
Surgical Oncologist

Dr. Raghavendra Naik

MBBS, MS (General Surgery), M.Ch (Surgical Oncology)

View Profile
Dr. Mohammed  Imaduddin
Surgical Oncologist

Dr. Mohammed Imaduddin

M.B.B.S, MS (General Surgery), M.Ch (Surgical Oncology)

View Profile
Dr. Vinay Mamidala
Surgical Oncologist

Dr. Vinay Mamidala

MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)

View Profile
Dr. Paila Gowri Naidu
Surgical Oncologist

Dr. Paila Gowri Naidu

MBBS, MS (General Surgery), M.Ch (Surgical Oncology), FMAS

View Profile
Dr. Venkata Sushma P
Radiation Oncologist

Dr. Venkata Sushma P

MBBS, MD (Radiation Oncology)

View Profile
Dr. Kirti Ranjan Mohanty
Radiation Oncologist

Dr. Kirti Ranjan Mohanty

MBBS, MD (Radiation Oncology)

View Profile
Dr. Gangadhar Vajrala
Radiation Oncologist

Dr. Gangadhar Vajrala

MBBS, MD (Radiation Oncology), MPH

View Profile
Dr. Basudev Pokhrel
Hematologist

Dr. Basudev Pokhrel

MBBS, M.D (Immunohematology & Blood Transfusion)

View Profile
Dr. Mohammed Imran
Interventional Radiologist

Dr. Mohammed Imran

View Profile
Dr. Vajja Sandeep Kumar
Surgical Oncologist

Dr. Vajja Sandeep Kumar

MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology

View Profile
Dr. Sridhar Kamani
Surgical Oncologist

Dr. Sridhar Kamani

MBBS, MS (General Surgery), DrNB (Surgical Oncology)

View Profile

Want a specific doctor for your case? Mention them when booking.

Book Free Consultation

Get a straight answer from a specialist

45 minutes, your reports reviewed, your questions answered in plain language.

Book Free Consultation Call 1800 202 8726

What is the difference between a minor and a major discordance?

Minor discordanceMajor discordance
What it meansA difference in grade, staging detail, or margin descriptionA different diagnosis, or a change significant enough to alter treatment
Does it change treatment?Usually notYes — surgery, systemic therapy, or radiotherapy planning may change
More common inComplex or rare tumour types; borderline or ambiguous findingsAny case where diagnosis depends on subtle microscopic features
Typically caught byInternal peer review before sign-off; multidisciplinary team discussionSecond-opinion review; sometimes only apparent when disease behaves unexpectedly

How does a laboratory catch errors before your report reaches you?

  1. Tissue collection and labelling

    The surgeon or interventionist labels the sample at the point it is taken — noting the site, side, and size. Any labelling ambiguity is raised before processing begins.

  2. Gross examination

    A pathologist examines the sample with the naked eye, selects representative sections, and records what is visible. This is the first clinical judgement in the chain.

  3. Tissue processing and slide preparation

    The selected tissue is embedded in wax, cut into thin sections, and stained so structures are visible under the microscope. Slide quality is checked before reporting.

  4. Primary reporting

    A pathologist examines the stained slides and prepares a report. Complex or unusual cases are referred for internal consultation before a final report is issued.

  5. Internal peer review

    Accredited laboratories require a proportion of all cases — and all complex or discordant cases — to be reviewed by a second pathologist before the report is released.

  6. Multidisciplinary team discussion

    Your oncologist presents your case to a team that includes a pathologist and a radiologist. Questions about the pathology are raised here before treatment is planned.

Did you know?

When oncology biopsy slides are sent for external expert review, studies audited by the College of American Pathologists find that a meaningful proportion result in a change to the diagnosis or grade.

Second-opinion review is not a sign of distrust in a laboratory. It is one of the most evidence-based quality steps available to a cancer patient.

Source: College of American Pathologists Quality and Patient Safety Committee

Explore 112 more Markers, Molecular Testing and Test Accuracy topics

HUB — How Accurate Is a Biopsy? Repeats, Errors and Second Opinions

HUB — IHC and Molecular Markers on a Biopsy

HUB — Labs, Slides and Second Opinions on a Biopsy

All Markers, Molecular Testing and Test Accuracy →

Next step

Still not sure what applies to you?

Send your reports across and a senior medical oncologist will go through what they mean, what is known, and what the options actually are.

Book Free Consultation Call 1800 202 8726
Common questions

Frequently asked questions

Does asking for a second opinion mean the first pathologist made a mistake?

No, and most oncologists do not interpret it that way. Pathology interpretation involves genuine uncertainty at the edges of classification — two experienced pathologists can read the same slide differently and both be within the range of defensible opinion. Asking for a second look is a quality step, not an accusation. Pathologists who work at institutions with formal peer review programmes review each other's cases routinely. A second opinion is part of good practice, not a challenge to it.

Which tumour types are most likely to produce a discordant second opinion?

Lymphomas, soft tissue sarcomas, rare epithelial tumours, and borderline ovarian tumours consistently show higher discordance rates when second opinions are studied, because their classification requires subspecialty knowledge and can involve genuinely ambiguous features. More common diagnoses — adenocarcinomas of the breast or colon, for example — tend to show lower rates. If you have been told you have a rare or unusual tumour type, the case for seeking specialist review is stronger.

How do I ask for my slides to be reviewed by a second pathologist?

Tell your oncologist at your next appointment that you would like an expert second opinion on the pathology. You do not need to arrange this yourself. Your treating team can request that your glass slides and paraffin blocks are sent to a specialist centre. In India, major cancer institutes accept referral material for review. The original slides belong to the laboratory that prepared them, but you and your treating team have the right to request that they are released.

Can a pathology error be found after treatment has already started?

Yes. Sometimes a second opinion is sought mid-treatment because the tumour is not responding as expected, a patient transfers to a different centre, or a multidisciplinary team meeting raises a question. Finding a discordance at that stage is disruptive, but catching an error at any point is better than not catching it. Treatment plans can be changed. The important thing is that the question is asked rather than avoided because it feels difficult.

Is a pathology second opinion different from a clinical second opinion?

Yes, and the difference matters. A pathology second opinion is a review of your actual slides by a second pathologist — ideally one with subspecialty expertise in your tumour type. A clinical second opinion is a second oncologist reviewing your case using your existing pathology report. Both are useful but they answer different questions. If there is any doubt about the diagnosis itself, the pathology review should come first, because everything else is built on what the slides say.

Full index

Browse all 701 biopsy topics

Every page in this section, grouped by the part of the journey it belongs to. Pick a group to see what is in it.

What Is a Biopsy?

What Is a Biopsy? Everything You Need to Know →

Types of Biopsy Compared

Which Biopsy Will You Have? Techniques Compared →

Preparing for a Biopsy

What to Expect on the Day of Your Biopsy →

Recovery and Aftercare

After a Biopsy: Recovery, Aftercare and Warning Signs →

Biopsy by Body Part

Biopsy by Body Part: What to Expect at Each Site →

Understanding Your Report

How to Read a Biopsy Report: Terms Explained →

IHC and Molecular Markers

IHC and Molecular Markers on a Biopsy: What They Mean →

Grading and Scoring Systems

Cytology & Prostate Scoring Systems Explained →

How Accurate Is a Biopsy?

How Accurate Is a Biopsy? Errors and Second Opinions →

If Your Result Is Benign

Your Biopsy Is Benign: What It Means and What Comes Next →

Call now Book free consultation