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Quality Assurance in Surgical Pathology Practice



Article By

Prema Saldanha





Quality assurance and quality control are used to achieve a desirable quality of service. The main objective of any quality assurance programme is to ensure the completeness, accuracy and timeliness of the service. The practice of Surgical Pathology is prone to human error and there should be a constant endeavor to minimize this error to provide the patients with the highest standard of care.



Introduction :

Quality assurance is a term used for a management system designed to achieve an acceptable level of service. Quality control (QC) measures are all the operational techniques and activities used to fulfil these requirements. The objective of any quality assurance programme is to ensure the completeness, accuracy and  timeliness of the service.[1] This  applies to  surgical pathology practice as well.

The practice of Pathology like any other field is prone to human error. There should be a constant endeavour of all concerned to minimize this error to provide the patients with the highest standard of care. Each one involved in  Pathology  reporting should be aware of one’s responsibilities and the medico legal repercussions if any, of the actions. Quality control in histopathology can reduce the possibility of misdiagnosis and thus also the risk of medico-legal issues.[2]

The Concept  of QC in  histopathology (HP)  is relatively new and complex. It may be due to the presence of many variables including descriptive nature of the report, lack of objective numerical data, individual judgement and bias with varying degrees of subjectivity, and lack of uniformity of the reporting pattern.[3]




A review of the  literature  from  peer-reviewed journals published in English was performed using electronic searching methods.


Results & Discussion :

Quality control is traditionally applicable to three phases of operation and the same may be applied to histopathology. These include the Pre-examination (pre-analytical) phase which includes all processes for generation of a good Examination  (analytical)  phase which is the interpretation  of slides and making an accurate diagnosis, and  the  Post-examination  (post- analytical)  phase  which includes  the  proper dispatching of result, storage/disposal of samples, slides and  blocks and  proper  retention  of test results.[3-8]

Errors in pre examination aspects include improper fixation or improper choice of fixation, incorrect patient identification, wrong identification of anatomic location as well as laterality of biopsy, forms without relevant clinical data/patient details, misplaced or lost specimens, inadequate volume/size, inadequate gross description or gross sampling, erroneous measurements, extraneous tissue (floaters), improper sections/inadequate serials, and poor staining and mounting quality.[4-8]

Major labelling issues could be that the specimen container is unlabelled; the patient name on the container does not match the name on the requisition/form; there is a significant mismatch between the source/site indicated on the container and the source/site indicated on the requisition/form; there is no identifiable tissue in the specimen container.[9] Less significant labelling issues are:  spelling discrepancies;  transposed numbers or small inaccuracies in 2nd identifiers; minor mismatch in description of specimen source/site; mismatch of left versus right designation; no second identifier; specimen site/source not indicated or specimen container labelled with patient information and/or site/source on lid.[9]



Use of Standard operating procedure (SOP) for sample accession, identification, acceptance/rejection, gross examination and sampling and all the steps that follow must be documented using simple language that can be understood by all. It should be available at the workplace and all technical staff should be aware of its contents. The laboratory may have designed its own “referral/requisition form” for histopathology and immunohistochemistry, which is made available to all areas of sample collection. The requisition form should include patient demographic data, nature and site of specimen, clinical diagnosis, all relevant clinical, investigative and intraoperative findings.[2,3]

The technique of sectioning and staining can be considered or described as more of an “art” than a quantifiable process with measurements. It varies with the skill and experience of the  technician. However, certain procedures should be followed on  a routine  basis. There  should  be  a planned changing of chemicals used for processing based on the number of tissues passed through. Usage of controls for routine and special stains daily as a routine  is strongly  recommended.  The paraffin used for impregnation and embedding should be of good  quality with  an  appropriate  melting point.[2,3]

Recording the temperature  of the paraffin bath, water floatation  bath  and  slide warming  table should be done on a daily basis. These  and other equipment  should  be of standard  quality and calibrated at periodic intervals. The microtome should be of good quality and serviced regularly. Periodic calibration of the micrometer should be made to ensure consistency of section thickness. The knife should be properly maintained. The use of disposable blades is recommended.[2,3]

Care should be taken not to induce tissue artefacts due to improper processing, sectioning, staining and mounting. The label affixed on the stained slide should be of an appropriate size so that it does not project  beyond  the  slide or  cover  the  tissue sections. The identification should be legible and should ideally carry the name of the laboratory. Using   bar   code  labels, one  can   incorporate demographic  data  such  as the  name  of the laboratory, the name of the patient, the laboratory ID number and the date. All the above steps when performed  should  be  signed  by the  person performing  the  individual steps, thus  bringing about accountability which makes the person more vigilant and  thus    there  is a lesser chance of negligence.[2,3]

Examination aspects include studying the slides along with relevant data and additional information,  and preparation  of the report with diagnosis. Unlike in other disciplines of laboratory medicine, assessment of analytical aspects in histopathology is not easy given the subjectivity of the reports.

Challenges faced in examination phase include change in categorical interpretation (e.g., benign to malignant, malignant to benign), false positives and  false negatives;  change within  the  same category of interpretation  (change in  type of malignancy) and change in threshold, change in information unrelated to the diagnosis and Frozen section–permanent section concordance.[4-6]

Misinterpretation  may occur due to inadequate specimen, non  representative  specimen  and incomplete clinical data. Uniformity in reporting can be achieved by using standard  protocols or templates.  The  WHO  and  CAP (College  of American Pathologists)  are  used  by  many pathologists.



These include intra-departmental  consultation; comparison with other reports (frozen/cytology/ histopathology); random case review (blinded re-reporting of random cases) by the same person (as a check for precision) and by a different person (as a  check for  accuracy);  hierarchical  form of reporting; intra- and inter-departmental conferences  (clinicopathological conference(CPC)/clinical rounds/ tumour boards); external consultations; review by experts and participation in continued medical education (CME) programmes.[2,8,10] Autopsies have medico- legal importance and hence it is important to find out the relevant history from the forensic expert before giving the final report.[2,11]

QC in Immunohistochemical analysis include checks for frequency and causes of repeated stains; turnaround   time  (TAT) issues; audit  for issues regarding integration of stains with morphologic diagnosis; annual  review of antibody  inventory and  frequency of use  and  consideration  of enrolment in external proficiency testing particularly for tests that  directly affect patient therapy, such as HER-2/neu immunostaining.[4-6]

QC in frozen section reporting include demarcation of a specific area for performing frozen sections; fresh tissue received for frozen section treated as infective and universal precautions be taken; left over tissue processed for permanent section; ensure that the turnaround time for frozen section/squash smears does not exceed 20-30 minutes and frozen section/squash smears be retained and filed along with the permanent sections for the stipulated time.[12]

Post examination aspects include report turnaround time, archiving of report data, and archiving of slides/blocks/specimens with ease of retrieval according to the guidelines put forth by the Royal College of Pathologists of the United Kingdom.[11,13]

Errors in post examination phase include case or patient  misidentification,  site misidentification (e.g., right  versus left),  incomplete  reports, verification errors during electronic sign-out or report finalization and report delivery errors.[3-6]


Most changes fall into 3 categories :

  1. Change in diagnosis. Some have used the terms amended or revised reports to indicate these Change.
  2. Change of information other than the diagnosis. Some have used the term corrected report for this change.
  3. Additional information, no changes to original report. Most have used the term addendum to report this change.[4-6]


Error reduction in surgical pathology is dependent on our understanding  of how errors occur and applying error-reduction strategies that have been developed in  other  areas of medicine. Surgical pathology is the analytic process of interpretation of tissue findings. However, errors occur not only as a result of diagnostic misinterpretation  but at any stage in  the  process were the  department receives, processes, and  reports  on  specimens. There is an inherently complex process with ample opportunity  for error  with deleterious  patient effects when things go wrong at any point in the process.[14]

Standard  recommendations  afford a framework for the creation of a standard protocol containing all of the components  that  are required  in the report  for  optimal  for  patient  care.[15] Many institutions include some type of grading scheme to determine what harm or potential harm may result from an error such as No harm or impact on patient care, slight harm or impact on patient care, significant harm or alteration of clinical management.[4-6]

External quality assessment (Proficiency testing) – Accrediting authorities insist that every laboratory should  have some  form  of external  quality assessment for all the tests performed under  its scope of activity. Organized EQA programs are available in other countries (CAP, UK-NEQAS). These  are either  prohibitively expensive or  not easily available in India.

The Inter-Laboratory Quality Assessment program for Histopathology (ILQA-HP) which is a part of the activities of parent organization ILQA- Bangalore is an important  programme in India. External quality assessment in histopathology to NABL accredited laboratories in India, with the long-term  goal of including  non  accredited laboratories into the programme is the goal. The scheme is divided into two portions : assessing the pre-analytical aspects and assessing the analytical aspects.[3]

Slices of formalin fixed tissue measuring approximately 1x1x0.5 cms are made from one common source and mailed to each of the participating laboratories who in turn process the tissue, make stained sections and return the slides to the nodal laboratory for pre-analytical assessment. Wide spectrum of tissues is sent. The stained sections are scored by an expert according to the scale: Score 1 = unsatisfactory, 2 = poor, 3 = average, 4 = good, 5 = excellent. A total of 15 marks are allotted as follows:

  1. Processing – 5 marks
  2. Sectioning – 5 marks
  3. Staining – 5 marks.[3]


Sections obtained from one common tissue block are stained with Haematoxylin and Eosin and distributed to all participating laboratories along with relevant clinical history and other information. All the diagnoses received within the notified period are analyzed and a consensus diagnosis is given.[3]


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References :

  1. Prematilleke I. Quality Control in Histopathology. CPSL National Guidelines.
  2. Venkatraman NT, Bhadranna  A,   Sadhana Shenoy  S,  Leeky Mohanty  L.  To    err    is human:  Quality  management  practices in surgical oral pathology, a safety net for medico-legal complications. J Oral Maxillofac Pathol. 2013 May-Aug; 17(2): 234–239.
  3. Iyengar JN. Quality control in the histopathology laboratory: An overview with stress on the need for a structured national external quality assessment scheme. Indian J Pathol Microbiol 2009; 52:1-5.
  4. Association of Directors of Anatomic and Surgical Pathology. Recommendations  for Quality Assurance and Improvement in Surgical and  Autopsy Pathology. Am J Clin Pathol 2006; 126: 337-40.
  5. Association of Directors of Anatomic and Surgical Pathology. Recommendations  for Quality Assurance and Improvement in Surgical and  Autopsy Pathology. Am J Surg Pathol 2006; 30: 1469-71.
  6. Cooper K, Association of Directors of Anatomic and Surgical Pathology. Recommendations for Quality Assurance and Improvement in Surgical and Autopsy Pathology. Hum Pathol 2006; 37: 985-88.
  7. Smith ML, Raab SS. Quality Assurance and Regulations for Anatomic Pathology. Essentials of Anatomic Pathology. In: Cheng L, Bostwick DG (eds.). Essentials of Anatomic Pathology, 3rd Ed, Springer Science+Business Media, LLC 2011, 481-7.
  8. Nakhleh RE. What is quality  in  surgical pathology? J Clin Pathol 2006; 59: 669-72.
  9. Layfield LJ, Anderson, GM. Specimen Labeling Errors in Surgical Pathology:  An 18-month Experience. Am J Clin Pathol. 2010;134:466-70.
  10. Dahl J. Quality, Assurance, Diagnosis, Treatment, and Patient Care. Pathologist Review,2006.
  11. Key Performance Indicators in Pathology – Recommendations from the Royal college Of Pathologists. 2013
  12. Chbani L, Mohamed S, Harmouch T, El Fatemi H, Amarti A. Quality assessment of intraoperative frozen sections: An analysis of 261 consecutive cases in a resource limited area: Morocco. Health 2012; 4; 433-435.
  13. CLIA Regulations: Retention Requirements (42CFR§493.1105).
  14. Nakhleh RE. Error Reduction in  Surgical Pathology. Arch Pathol Lab Med 2006;130:630-32.
  15. Goldsmith JD, Siegal GP, Suster S, Wheeler TM, Brown RW. Reporting Guidelines for Clinical Laboratory Reports in Surgical Pathology. Arch Pathol Lab Med 2008;132:,1608-16.