Quality Assurance in Surgical Pathology Practice
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.
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. 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.
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.
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. 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.
STEPS TO ACHIEVE QUALITY CONTROL:
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.
STEPS TO ACHIEVE QUALITY CONTROL :
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.
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 :
- Change in diagnosis. Some have used the terms amended or revised reports to indicate these Change.
- Change of information other than the diagnosis. Some have used the term corrected report for this change.
- 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.
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. 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.
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:
- Processing – 5 marks
- Sectioning – 5 marks
- Staining – 5 marks.
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.
- Prematilleke I. Quality Control in Histopathology. CPSL National Guidelines. http://www.slcog.lk/img/guidelines/Other%20national%20Gidelines/Pathol.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Nakhleh RE. What is quality in surgical pathology? J Clin Pathol 2006; 59: 669-72.
- Layﬁeld LJ, Anderson, GM. Specimen Labeling Errors in Surgical Pathology: An 18-month Experience. Am J Clin Pathol. 2010;134:466-70.
- Dahl J. Quality, Assurance, Diagnosis, Treatment, and Patient Care. Pathologist Review,2006. http://psqh.com/marapr06/pathologist.html
- Key Performance Indicators in Pathology – Recommendations from the Royal college Of Pathologists. 2013
- 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.
- CLIA Regulations: Retention Requirements (42CFR§493.1105).
- Nakhleh RE. Error Reduction in Surgical Pathology. Arch Pathol Lab Med 2006;130:630-32.
- 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.