DOI:10.1111/cyt.12245
INVITED REVIEW
Development of a technical external quality assurance scheme in non-gynaecological cytology in UK P. A. Cross*, C. Hodgson†, J. Crossley‡ and B. Crossley§ *Department of Pathology, The Pathology Centre, Queen Elizabeth Hospital, Gateshead, Tyne and Wear, UK, †UK NEQAS CPT, Department of Pathology, The Pathology Centre, Queen Elizabeth Hospital, Gateshead, Tyne and Wear, UK, ‡
Department of Cytology, Royal Hallamshire Hospital, Sheffield, UK, §The Royal Oldham Hospital, Oldham, Lancashire, UK
Accepted for publication 31 January 2015
P. A. Cross, C. Hodgson, J. Crossley and B. Crossley Development of a technical external quality assurance scheme in non-gynaecological cytology in UK
Abstract Technical external quality assurance (EQA) schemes are well established for histopathology and cervical cytology but, to date, sadly lacking for diagnostic cytology (DC). This timely review redresses the balance by describing the development and evaluation of a technical EQA scheme for DC available to the UK, Europe and beyond. Keywords: diagnostic cytology EQA, cytology quality, cytology technical quality
Introduction The field of DC is vast, with numerous publications on the morphological criteria and staining techniques used to reach a diagnosis,1,2 but comparatively little has been written about the technical aspects of the preparations used or acceptable practice in this respect.3,4 In the UK, many laboratories report cervical cytology and DC. Comprehensive guidance exists for cervical cytology within the English Cervical Screening Programme (CSP) about laboratory function, specimen reporting and quality assurance in general.5 One such document6 gives details of the staining criteria and how these are assessed for the Papanicolaou stain within the CSP as part of a mandatory EQA scheme. Such guidance has helped to produce greater consistency of sample staining and to raise technical standards in cervical cytology. There is a striking contrast with the lack of accepted guidance in DC.
In the UK, most laboratories are accredited with Clinical Pathology Accreditation (CPA) (UK) Ltd. under International Organization for Standardization (ISO) standards.7 This requires laboratories to take part in any relevant EQA schemes. Technical cellular pathology EQA schemes are largely provided by UK NEQAS for CPT (United Kingdom National External Quality Assessment Service for Cellular Pathology Techniques).8 For many years, this has provided EQA for haematoxylin and eosin and specialist histology stains, neuropathology, renal biopsy pathology and muscle histochemistry. The lack of technical guidance for DC has been highlighted previously,9 and the lack of an external independent national accredited EQA scheme has often been discussed; however, few concrete steps have been taken to rectify this. We detail here the design, development and introduction of such a scheme. Background
Correspondence Dr P A Cross, Department of Pathology, The Pathology Centre, Queen Elizabeth Hospital, Gateshead, Tyne and Wear, NBE9 6SX E-mail: [email protected] © 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
In 2011, the British Association for Cytopathology (BAC) was keen to promote, develop and apply appropriate standards to all cytology, and perceived the lack of a technical quality scheme within DC as a major issue. A survey of BAC members revealed
71
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that 76% of respondents would take part in such a scheme if it existed.10 BAC then approached UK NEQAS CPT to discuss the development of a scheme and, following discussions, a draft protocol was developed. BAC agreed to fund the cost of the pilot phase. The draft protocol was developed by senior BAC members and the UK NEQAS CPT scheme manager, using existing UK NEQAS CPT protocols and specialist modules as a basis for format and style. The cytology contributors were asked to help assess the draft protocol within two pilots. To test the draft protocol, BAC and current UK NEQAS CPT scheme members were invited to take part in a pilot study during 2012/2013. Seventy-two laboratories expressed a desire to take part. Two pilot rounds were planned to test the draft protocol. Thirty-five laboratories representing a wide range of practice in the UK and overseas were chosen for pilot one, and all 72 laboratories were invited into pilot two. There was no cost for participation in these two pilots. All laboratories were sent the draft protocol for inspection and comment. Pilot one asked the laboratories for a serous fluid (ascitic/pleural) and urine sample for assessment. Results from each laboratory’s slide submissions were fed back individually. Comments were encouraged on the protocol and this was amended over the two pilot rounds. Following the two pilots, the protocol was updated, together with the documentation of the criteria, and was used as the basis for a DC technical EQA scheme. The protocol was available via the UK NEQAS CPT website,8 and was also sent to all contributing laboratories. All UK NEQAS CPT scheme participants, including those who had taken part in the pilot schemes, were invited to take part as paying members of the scheme, and the first formal round was held in January 2014; to date (January 2015), seven rounds have been undertaken. In common with other UK NEQAS CPT schemes, this scheme operates six EQA rounds per year. Protocol development The initial protocol drew upon existing guidance to suggest standards and develop areas for assessment in the technical quality of DC samples covering aspects such as sample preparation, staining and mounting. Definitions of the criteria were devised, with an explanation of the scoring criteria and model descriptions, and incorporated in a DC criteria
handbook. Existing guidance identified that Papanicolaou and Romanowsky stains were advocated for use in all samples, and haematoxylin and eosin (H&E) was not.4 The scheme would assess samples only if the two accepted stains had been used; it did not assess any H&E-stained samples submitted. For the pilot schemes, assessors worked in pairs, assessed the submitted samples at a double-headed microscope and agreed a score out of five for the overall technical quality. From the second pilot onwards, the same double assessor approach was used, but with each assessor scoring individually, to produce a combined overall score out of ten. Submitted slides that scored four or below were passed to a second pair of assessors for further assessment before a final score was issued. If there was a discrepancy of two or more between the scores of the initial pair of assessors, e.g. three and five, or if there was a discrepancy of pass/fail between the initial pair of assessors, the slide was also passed to a second pair of assessors for assessment. Individual laboratory reports were produced for all participating laboratories showing their score for that run assessment. Full details are available on the UK NEQAS CPT website. All assessments were held over 1 day, and allowed for discussion between assessors and refinement and development of the protocol. Bespoke software to aid with assessment, recording and result production/laboratory feedback was developed by UK NEQAS and used for the pilots and subsequent rounds. To try to minimize assessor bias and variation, a short discussion of the protocol with examples was undertaken prior to each assessment, which developed over the rounds into a structured process with assessors formally assessed against an agreed set of prescored samples to demonstrate competency and ensure consistency. An assessor educational and training day has been developed, and assessors are only allowed to assess if they have completed such a session. Samples were photographed and used as digital images accessible via the UK NEQAS CPT website for participating laboratories (and assessors) as examples to help in the understanding of the scheme criteria and definitions. Best methods are requested from high scoring participants and are available both on the website and in a newsletter, produced three times a year. Three participant feedback meetings have indicated a high level of satisfaction with the scheme. © 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
Non-gynaecological cytology EQA development
Serous cavity fluids and urine samples were used for the pilots and first two rounds proper, as these are the most common DC samples in UK practice. In rounds three to five, the urine samples were replaced by respiratory samples. Discussion The appetite for such a scheme is apparent in that, from a non-existent scheme prior to 2012, there are now a total of 159 participating laboratories. These are mostly in the UK, but also include laboratories from Europe and further afield. The acceptance of the scheme has been overwhelming, and the comments received indicate very little dissatisfaction with the protocol. Although very much in its early days, what has the scheme achieved? One basic aim is to raise the technical quality of DC samples by peer comparison and the sharing of good practice. The scheme allows laboratories to assess the technical quality of their DC samples against other laboratories using a transparent protocol. It also allows for educational feedback via the definitions used and digital photographic examples. The development of webbased educational systems, such as the TASTE (Telepathological ASsessment of histopathological and cytological TEchniques) project,11 will also help raise standards and promote quality. The scheme has allowed laboratories to become better aware of guidance (where it exists) and to share best methods and demonstrate their quality objectively. It also allows for the collection of data on laboratory practice with regard to DC, and has highlighted the huge variation in preparation techniques and the number and type of samples used. Now that the DC scheme is established within the repertoire of UK NEQAS CPT, a second survey is being issued to all participants to further develop the scheme. The scheme has also highlighted the continuing use of H&E for cytology reporting, which existing UK guidance does not advocate,4 and the scheme appears to be being used in some organizations to amend laboratory practice. It would appear that the use of the H&E stain in cytology is one of longstanding historic practice and, often, pathologist preference. Any EQA scheme must reflect agreed professional guidance and, if such guidance were to change, then the scheme must reflect this. Adequacy for technical assessment is difficult to define, given that there is virtually no guidance about actual sample adequacy for DC. DC covers © 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
nearly all body sites and there can be a huge variation in the sample content depending on the site. As such, and within a technical EQA scheme, it is important to distinguish ‘diagnostic’ adequacy from ‘technical’ adequacy. For the purposes of the technical EQA scheme, the requirement is for sufficient cell content to assess preparation and staining techniques. In the absence of any published or agreed criteria, as a guide, we advise that a submitted slide for scheme assessment should contain at least five fields, each with at least 10 cells (excluding inflammatory and/ or blood-derived cells) per 920 high-power field for assessment. Although not evidence based, it provides a working pragmatic definition for assessment. Many samples assessed are of a high technical standard, and the widespread use of liquid-based sample techniques appears to allow for a consistent approach to sample handling. However, many cytology samples suffer from obscuration by blood, from being too thickly spread or from being affected by air drying, cracking or poor cover slip mounting in circumstances in which the laboratory has full control over sample processing. It is apparent that some laboratories are presented samples taken by clinicians which are of very poor quality, and there is very little even the best laboratory can do with such substandard samples. Some laboratories appear to be using the scheme to offer feedback to clinicians about this. It should be noted that UK NEQAS for CPT also offers a validation service for participants having issues with staining or those validating new methodology or equipment. In the future, the scheme will need to reflect the wide range of cytology samples, not only by site, but also by technical method, and may require more specialist sample assessment. The need for such a scheme is demonstrated by its high uptake rate, but, like all such schemes, it must help raise standards to be of use to its participants. It must also evolve to reflect and potentially help validate new cytology technical preparation techniques as the specialty develops in the future.
References 1. Koss LG, Melamed MR. Koss’ Diagnostic Cytology and its Histopathologic Basis, 5th edn. Baltimore: Wolters Kluwer; 2005. 2. Gray W, Kocjan G. Diagnostic Cytopathology, 3rd edn. China: Elsevier; 2010.
73
74
P. A. Cross et al.
3. Chandra A, Cross P, Denton K et al. The BSCC code of practice – exfoliative cytopathology (excluding gynaecological cytopathology). Cytopathology 2009;20: 211–23. 4. Tissue pathways for exfoliate and fine needle aspiration cytology. The Royal College of Pathologists: London; 2010 http://www.rcpath.org/Resources/RCPath/Migrated %20Resources/Documents/G/g086tpexfoliativecytologyfnacytology.pdf 5. NHSCSP Publications list, NHS CSP, UK http://www. cancerscreening.nhs.uk/cervical/publications/numberedindex.html 6. NHS CSP Publication No 15 External Quality Assessment Scheme for Gynaecological Cytopathology Ver-
7. 8. 9.
10.
11.
sion 5 http://www.cancerscreening.nhs.uk/cervical/ publications/nhscsp15.html Clinical Pathology Accreditation, UK http://www.ukas.com/ services/CPA/Clinical_Pathology_Accreditation_CPA.asp UK NEQAS for CPT, UK, http://www.ukneqascpt.org.uk/ content/PageServer.asp?S=558056691&C=1252&ID=311 Egan M, Gray J. Quality procedures in non-gynaecological cytology laboratories in England and Wales. Cytopathology 1999;10:240–9. British Association for Cytopathology, UK http://www. britishcytology.org.uk/news/viewnewsitem.asp?id=214& num=28 TASTE Project EU http://www.system.tasteproject.eu/ system/
© 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
Copyright of Cytopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
INVITED REVIEW
Development of a technical external quality assurance scheme in non-gynaecological cytology in UK P. A. Cross*, C. Hodgson†, J. Crossley‡ and B. Crossley§ *Department of Pathology, The Pathology Centre, Queen Elizabeth Hospital, Gateshead, Tyne and Wear, UK, †UK NEQAS CPT, Department of Pathology, The Pathology Centre, Queen Elizabeth Hospital, Gateshead, Tyne and Wear, UK, ‡
Department of Cytology, Royal Hallamshire Hospital, Sheffield, UK, §The Royal Oldham Hospital, Oldham, Lancashire, UK
Accepted for publication 31 January 2015
P. A. Cross, C. Hodgson, J. Crossley and B. Crossley Development of a technical external quality assurance scheme in non-gynaecological cytology in UK
Abstract Technical external quality assurance (EQA) schemes are well established for histopathology and cervical cytology but, to date, sadly lacking for diagnostic cytology (DC). This timely review redresses the balance by describing the development and evaluation of a technical EQA scheme for DC available to the UK, Europe and beyond. Keywords: diagnostic cytology EQA, cytology quality, cytology technical quality
Introduction The field of DC is vast, with numerous publications on the morphological criteria and staining techniques used to reach a diagnosis,1,2 but comparatively little has been written about the technical aspects of the preparations used or acceptable practice in this respect.3,4 In the UK, many laboratories report cervical cytology and DC. Comprehensive guidance exists for cervical cytology within the English Cervical Screening Programme (CSP) about laboratory function, specimen reporting and quality assurance in general.5 One such document6 gives details of the staining criteria and how these are assessed for the Papanicolaou stain within the CSP as part of a mandatory EQA scheme. Such guidance has helped to produce greater consistency of sample staining and to raise technical standards in cervical cytology. There is a striking contrast with the lack of accepted guidance in DC.
In the UK, most laboratories are accredited with Clinical Pathology Accreditation (CPA) (UK) Ltd. under International Organization for Standardization (ISO) standards.7 This requires laboratories to take part in any relevant EQA schemes. Technical cellular pathology EQA schemes are largely provided by UK NEQAS for CPT (United Kingdom National External Quality Assessment Service for Cellular Pathology Techniques).8 For many years, this has provided EQA for haematoxylin and eosin and specialist histology stains, neuropathology, renal biopsy pathology and muscle histochemistry. The lack of technical guidance for DC has been highlighted previously,9 and the lack of an external independent national accredited EQA scheme has often been discussed; however, few concrete steps have been taken to rectify this. We detail here the design, development and introduction of such a scheme. Background
Correspondence Dr P A Cross, Department of Pathology, The Pathology Centre, Queen Elizabeth Hospital, Gateshead, Tyne and Wear, NBE9 6SX E-mail: [email protected] © 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
In 2011, the British Association for Cytopathology (BAC) was keen to promote, develop and apply appropriate standards to all cytology, and perceived the lack of a technical quality scheme within DC as a major issue. A survey of BAC members revealed
71
72
P. A. Cross et al.
that 76% of respondents would take part in such a scheme if it existed.10 BAC then approached UK NEQAS CPT to discuss the development of a scheme and, following discussions, a draft protocol was developed. BAC agreed to fund the cost of the pilot phase. The draft protocol was developed by senior BAC members and the UK NEQAS CPT scheme manager, using existing UK NEQAS CPT protocols and specialist modules as a basis for format and style. The cytology contributors were asked to help assess the draft protocol within two pilots. To test the draft protocol, BAC and current UK NEQAS CPT scheme members were invited to take part in a pilot study during 2012/2013. Seventy-two laboratories expressed a desire to take part. Two pilot rounds were planned to test the draft protocol. Thirty-five laboratories representing a wide range of practice in the UK and overseas were chosen for pilot one, and all 72 laboratories were invited into pilot two. There was no cost for participation in these two pilots. All laboratories were sent the draft protocol for inspection and comment. Pilot one asked the laboratories for a serous fluid (ascitic/pleural) and urine sample for assessment. Results from each laboratory’s slide submissions were fed back individually. Comments were encouraged on the protocol and this was amended over the two pilot rounds. Following the two pilots, the protocol was updated, together with the documentation of the criteria, and was used as the basis for a DC technical EQA scheme. The protocol was available via the UK NEQAS CPT website,8 and was also sent to all contributing laboratories. All UK NEQAS CPT scheme participants, including those who had taken part in the pilot schemes, were invited to take part as paying members of the scheme, and the first formal round was held in January 2014; to date (January 2015), seven rounds have been undertaken. In common with other UK NEQAS CPT schemes, this scheme operates six EQA rounds per year. Protocol development The initial protocol drew upon existing guidance to suggest standards and develop areas for assessment in the technical quality of DC samples covering aspects such as sample preparation, staining and mounting. Definitions of the criteria were devised, with an explanation of the scoring criteria and model descriptions, and incorporated in a DC criteria
handbook. Existing guidance identified that Papanicolaou and Romanowsky stains were advocated for use in all samples, and haematoxylin and eosin (H&E) was not.4 The scheme would assess samples only if the two accepted stains had been used; it did not assess any H&E-stained samples submitted. For the pilot schemes, assessors worked in pairs, assessed the submitted samples at a double-headed microscope and agreed a score out of five for the overall technical quality. From the second pilot onwards, the same double assessor approach was used, but with each assessor scoring individually, to produce a combined overall score out of ten. Submitted slides that scored four or below were passed to a second pair of assessors for further assessment before a final score was issued. If there was a discrepancy of two or more between the scores of the initial pair of assessors, e.g. three and five, or if there was a discrepancy of pass/fail between the initial pair of assessors, the slide was also passed to a second pair of assessors for assessment. Individual laboratory reports were produced for all participating laboratories showing their score for that run assessment. Full details are available on the UK NEQAS CPT website. All assessments were held over 1 day, and allowed for discussion between assessors and refinement and development of the protocol. Bespoke software to aid with assessment, recording and result production/laboratory feedback was developed by UK NEQAS and used for the pilots and subsequent rounds. To try to minimize assessor bias and variation, a short discussion of the protocol with examples was undertaken prior to each assessment, which developed over the rounds into a structured process with assessors formally assessed against an agreed set of prescored samples to demonstrate competency and ensure consistency. An assessor educational and training day has been developed, and assessors are only allowed to assess if they have completed such a session. Samples were photographed and used as digital images accessible via the UK NEQAS CPT website for participating laboratories (and assessors) as examples to help in the understanding of the scheme criteria and definitions. Best methods are requested from high scoring participants and are available both on the website and in a newsletter, produced three times a year. Three participant feedback meetings have indicated a high level of satisfaction with the scheme. © 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
Non-gynaecological cytology EQA development
Serous cavity fluids and urine samples were used for the pilots and first two rounds proper, as these are the most common DC samples in UK practice. In rounds three to five, the urine samples were replaced by respiratory samples. Discussion The appetite for such a scheme is apparent in that, from a non-existent scheme prior to 2012, there are now a total of 159 participating laboratories. These are mostly in the UK, but also include laboratories from Europe and further afield. The acceptance of the scheme has been overwhelming, and the comments received indicate very little dissatisfaction with the protocol. Although very much in its early days, what has the scheme achieved? One basic aim is to raise the technical quality of DC samples by peer comparison and the sharing of good practice. The scheme allows laboratories to assess the technical quality of their DC samples against other laboratories using a transparent protocol. It also allows for educational feedback via the definitions used and digital photographic examples. The development of webbased educational systems, such as the TASTE (Telepathological ASsessment of histopathological and cytological TEchniques) project,11 will also help raise standards and promote quality. The scheme has allowed laboratories to become better aware of guidance (where it exists) and to share best methods and demonstrate their quality objectively. It also allows for the collection of data on laboratory practice with regard to DC, and has highlighted the huge variation in preparation techniques and the number and type of samples used. Now that the DC scheme is established within the repertoire of UK NEQAS CPT, a second survey is being issued to all participants to further develop the scheme. The scheme has also highlighted the continuing use of H&E for cytology reporting, which existing UK guidance does not advocate,4 and the scheme appears to be being used in some organizations to amend laboratory practice. It would appear that the use of the H&E stain in cytology is one of longstanding historic practice and, often, pathologist preference. Any EQA scheme must reflect agreed professional guidance and, if such guidance were to change, then the scheme must reflect this. Adequacy for technical assessment is difficult to define, given that there is virtually no guidance about actual sample adequacy for DC. DC covers © 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
nearly all body sites and there can be a huge variation in the sample content depending on the site. As such, and within a technical EQA scheme, it is important to distinguish ‘diagnostic’ adequacy from ‘technical’ adequacy. For the purposes of the technical EQA scheme, the requirement is for sufficient cell content to assess preparation and staining techniques. In the absence of any published or agreed criteria, as a guide, we advise that a submitted slide for scheme assessment should contain at least five fields, each with at least 10 cells (excluding inflammatory and/ or blood-derived cells) per 920 high-power field for assessment. Although not evidence based, it provides a working pragmatic definition for assessment. Many samples assessed are of a high technical standard, and the widespread use of liquid-based sample techniques appears to allow for a consistent approach to sample handling. However, many cytology samples suffer from obscuration by blood, from being too thickly spread or from being affected by air drying, cracking or poor cover slip mounting in circumstances in which the laboratory has full control over sample processing. It is apparent that some laboratories are presented samples taken by clinicians which are of very poor quality, and there is very little even the best laboratory can do with such substandard samples. Some laboratories appear to be using the scheme to offer feedback to clinicians about this. It should be noted that UK NEQAS for CPT also offers a validation service for participants having issues with staining or those validating new methodology or equipment. In the future, the scheme will need to reflect the wide range of cytology samples, not only by site, but also by technical method, and may require more specialist sample assessment. The need for such a scheme is demonstrated by its high uptake rate, but, like all such schemes, it must help raise standards to be of use to its participants. It must also evolve to reflect and potentially help validate new cytology technical preparation techniques as the specialty develops in the future.
References 1. Koss LG, Melamed MR. Koss’ Diagnostic Cytology and its Histopathologic Basis, 5th edn. Baltimore: Wolters Kluwer; 2005. 2. Gray W, Kocjan G. Diagnostic Cytopathology, 3rd edn. China: Elsevier; 2010.
73
74
P. A. Cross et al.
3. Chandra A, Cross P, Denton K et al. The BSCC code of practice – exfoliative cytopathology (excluding gynaecological cytopathology). Cytopathology 2009;20: 211–23. 4. Tissue pathways for exfoliate and fine needle aspiration cytology. The Royal College of Pathologists: London; 2010 http://www.rcpath.org/Resources/RCPath/Migrated %20Resources/Documents/G/g086tpexfoliativecytologyfnacytology.pdf 5. NHSCSP Publications list, NHS CSP, UK http://www. cancerscreening.nhs.uk/cervical/publications/numberedindex.html 6. NHS CSP Publication No 15 External Quality Assessment Scheme for Gynaecological Cytopathology Ver-
7. 8. 9.
10.
11.
sion 5 http://www.cancerscreening.nhs.uk/cervical/ publications/nhscsp15.html Clinical Pathology Accreditation, UK http://www.ukas.com/ services/CPA/Clinical_Pathology_Accreditation_CPA.asp UK NEQAS for CPT, UK, http://www.ukneqascpt.org.uk/ content/PageServer.asp?S=558056691&C=1252&ID=311 Egan M, Gray J. Quality procedures in non-gynaecological cytology laboratories in England and Wales. Cytopathology 1999;10:240–9. British Association for Cytopathology, UK http://www. britishcytology.org.uk/news/viewnewsitem.asp?id=214& num=28 TASTE Project EU http://www.system.tasteproject.eu/ system/
© 2015 John Wiley & Sons Ltd Cytopathology 2015, 26, 71–74
Copyright of Cytopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
