External Quality Assessment (EQA) Schemes in Immunohaematology

1. External Quality Assessment (EQA) Schemes in Immunohaematology Jenny White, Scheme Manager UK NEQAS for Blood Transfusion Laboratory Practice (BTLP)

2. What is EQA? Objective comparison of results from a group of laboratories, where each tests identical specimens of ‘known’ but undisclosed content Can be local / regional / national / international Organised by an EQA Scheme

3. EQA cycle Scheme Participants Both

4. IQC EQA Competency Assessment Today’s results same as yesterday’s Your result the same as other laboratories’ result Perform and interpret test. Decide on follow up tests / actions. Instrument 1 same as Instrument 2 Booking in samples Requires same level of testing as clinical samples Demonstrates day to day reproducibility Demonstrates competency of individual staff members Demonstrates that system works

5. EQAS aims / benefits • Identify problems in individual laboratories • Deliver advice / education • Support accreditation (ISO 15189 in UK labs) • Demonstrate weaknesses (& strengths) in systems • Provide evidence for guidelines and manufacturers • Provide impetus for change Dependent on EQA testing reflecting clinical practice

6. Network of 390 schemes 26 centres UK NEQAS Consortium not-for-profit company limited by guarantee and a UK Registered Charity www.ukneqas.org >8,000 labs from >100 countries regularly participate in UK NEQAS exercises UK NEQAS is part of the

7. UK NEQAS Schemes • Membership open to all • Subscription based funding • Independent and impartial • Confidential reporting • Evolving to reflect clinical practice • Informed by expert opinion (advisors) • Accountable within wider quality framework

8. Dept. of Health RCPath UKAS ISO 17043 National Quality Assurance Advisory Panels and Joint Working Group UK NEQAS Organisation Inspection and accreditation Unsatisfactory Performance in UK Code of practice, designation of status, approval of subscriptions UK NEQAS SCHEME Professional advice and review Performance monitoring and education Steering Committee and SAGs What are our external accountabilities? Participants

9. Performance standards

10. UK NEQAS BTLP -EQA schemes and pilot schemes • Pre -transfusion testing • Other full schemes • FMH • ABO titration • Pilots Schemes • Red cell genotyping • DAT • Extended phenotyping • Antenatal titration • ‘Emergency’ provision of blood • PTT practice surveys Providing EQA services to 350 UK hospital and red cell reference laboratories &, 650 non-UK

11. Pre-transfusion testing EQA scheme (PTT) Tests assessed Schedule to include Antibody mixtures Weak antibodies Incompatibility due to IgG and ABO antibodies Anomalous ABO and / or D Emergency and urgent scenarios • ABO/D typing • Antibody screening and identification • Establishing compatibility (serology or EI) • Red cell phenotyping Explore areas highlighted by SHOT and with variation in practice

12. UK BSH guidance • BCSH guidelines for pre-transfusion compatibility procedures in blood transfusion laboratories (2013) • BCSH guidelines for the specification and use of information technology systems in blood transfusion practice (2014) www.bcshguidelines.com

13. UK Haemovigilance Scheme Serious Hazards of Transfusion (SHOT) Transfusion Incident Actual Error EQA exercise Potential Error SHOT Near Miss

14. EQA Material • Provided by NHSBT • Prepared in 3L pools and split into 3mL samples Nine samples per exercise • 3 ‘patient’ whole blood • 3 ‘patient’ plasma • 3 ‘donors’ red cells

15. Cycle of in-house testing

16. UK PTT error rates over time(% opportunity for error) UK 2017: 99% of all routine ABO/D typing and antibody screening fully automated

17. ABO/D groupingErrors mainly procedural Exceptions • DAT positive samples • D Variants • Dual population of red cells ABO and/or D

18. Detection of dual populations in EQA over time Mixed field reaction • ? Occurs in test system used • ? Is recognised • ? If recognised, is a safe a ABO/D interpretation made

19. Exercise 18R2 A+/O- dual population interpretationFemale age 28, recently transfused Reaction with anti-A vs. interpretation for Patient 1 (n=377) ? Influenced by reverse group (A) Reaction with anti-D vs. interpretation for Patient 1 (n=377) Patient 1 Female, age 28 D + unsafe result

20. 17R5 D negative, DAT+ sample Front Back Anti-D reagents potentiated with PEG Will react with IgG coating on red cells regardless even if no D antigen +ve reaction in control well invalidates the test

21. 17R5 – rr (cde/cde) DAT +ve sample • 60/99 labs using this reagent reported +ve reactions vs. anti-D and/or control; 52 reported D negative as: • Aware of the limitations of technology in use • Followed manufacturer’s instructions for interpretation • Had policy for defining and investigating anomalous ABO/D results • Staff had knowledge to recognise potential sources of error BUT…. 8/60 made an interpretation of D+ or D weak/variant

22. Antibody Screen • Historically EQA identified problems with profile of screening cells and use of pooled cells, manual testing • Rarely problems with sensitivity now • Errors usually procedural or interpretative • EQA less likely to identify unknown problem as have IQC for mostly automated, standardised procedure • Few errors but high impact… as supporting electronic issue

23. Establishing compatibility in UK - EQA data

24. Exercise 17E4 – weak anti-E 4 labs reported a negative antibody screen • 3 had equivocal reactions in the initial screen • 2 discounted a weak positive reaction in the screen • 1 on the basis of a field safety notice relating to screening QC samples • 1 due to a pre-existing problem with false positive screening reactions • 1 protocol for investigating equivocal screen not followed • 1 negative initial screen • on repeat negative on one analyser and positive on another

25. Crossmatching • Error rate for missed incompatibility significant • EQA reveals procedural and technical problems • Insensitivity of IAT and transposition errors

26. Screen Crossmatch Reactants Donor cells Unknown zygosity Variable condition Require manipulation All reactants variable Process Manual steps even if automation used Often under pressure Reactants • Reagent red cells • Known antigen profile • Stored in optimal medium • At correct cell suspension • Controlled with weak abs. Process • Usually batch testing • Usually automated

27. Emergency Exercise 15R1 • One extra whole blood sample • Provide 4 units of red cells in 10 minutes • Report extent of testing and results of ABO/D if undertaken Patient group B D negative

28. Emergency issue of group specific red cells Following an rapid group, a 2nd test to detect ABO incompatibility should be undertaken prior to release of group specific red cells (BSH 2012) Immediate spin crossmatch ABO group on new aliquot / sample

29. Provision of blood in 10 mins 233 (72%) did an initial group 99 grouped 2 aliquots or one group + I/S 134 one group only 99 2nd group 8 used same aliquot 105 no I/S crossmatch 63 issued group O 14 (6%) issued group B on inadequate testing 10 (4%) still issued group O, even after receipt and confirmatory testing of 2nd sample.

30. Antibody Identification • Manual steps – procedural error • Interpretation – lack of specialist knowledge • Protocols for inclusion / exclusion lacking • More often protocols not followed • CAPA often involves re-training / education • Resources also an issue – option to submit panels for review if unable to complete ID

31. 2006 Theoretical ID - Female age 72, A D Negative

32. 2006 Theoretical ID - Female age 72, A D Negative

33. 2006 Theoretical ID - results • 165/356 (46%) positively identified anti-M, where reactions could have been due to D+K • Of the 165 • 12 did not consider anti-D • 18 did not consider anti-K • 16% overall did not select D-K- blood for tx

34. ‘UI’ Submission - in place 2006 - 2018 Report: • What can be identified (if anything) + UI • What cannot be excluded • Reasons why ID cannot be completed • Panel profiles (ID and screen) • If agreed then no penalty for incomplete ID • If no UI submission made then assessment is on antibodies positively ID only... not able to assess whether interpretation of UI is correct if cannot see full results • If disagree then letter to explain why – opportunity to target education

35. November 2016 UK NEQAS BTLP Exercise 16E10 DISCUSSION AND LEARNING POINTS • A process of exclusion should be undertaken as the first step in antibody identification. For specificities that cannot be excluded based on the phenotype, BCSH guidance is that “A single example only of each phenotype is sufficient for exclusion” and “The presence of anti-Jka, anti-Jkb, anti-S, anti-s, anti-Fya and anti-Fyb should be excluded using red cells having homozygous expression of the relevant antigen” 3. • BCSH guidance on inclusion is that “Antibody specificity should only be assigned when the plasma is reactive with at least two examples of reagent red cells expressing the antigen and non-reactive with at least two examples of reagent red cells lacking the antigen” 3. • There is no requirement to exclude antibodies of low clinical significance and/or low frequency, as long as all the positive reactions obtained have been accounted for.

36. Red cell phenotypingEQA • Antigens CcEe, Kk, Ss, MN, Fya, Fyb, Jka, Jkb • EQA error rate in the UK 0.5 – 1% • Data entry, transposition in testing • Issues with reagents and/or controls • Not noticing unlikely results • e.g. all 3 ‘donors’ as S-s-

37. 18R2 Jkbtyping – unusually high error rate Additional survey of all UK labs • Association with an anti-Jkbtyping reagent • New reagent supplied by a reagent company but some labs did not check product insert • Tube method – many used CAT as recommended for previous reagent • Some false negatives even where method followed – problem with reagent – reported to MHRA • General problems with phenotyping also identified • 25% of all laboratories selected a Jk(a-b+) cell as the positive control for Jkb typing • Typing reported on weak reactions obtained for test and/or control

38. Investigating an EQA error • Look for the ‘root cause’ of the error • Keep in mind that this is ‘organisational’ not ‘individual’ assessment • Understand implications for equivalent clinical practice • Share with EQA scheme so they can share learning with all participants • Document and carry out corrective and preventative actions (CAPA) • Accreditation – looking at response to EQA rather than no errors

39. Response to EQA errors

40. Example CAPA - EQA phenotyping error: anti-Jkb reagent is found not to be working as expected

41. What have we learnt through EQA? • Importance of following manufacturers’ instructions (Phenotyping) • Importance of selecting appropriate controls (Phenotyping) • Risks in not understanding characteristics of reagents (D typing) • Knowledge gaps in recognising anomalous results (ABO/D) • Knowledge gaps in interpreting results (ABO/D and antibody ID) • Need for policy to investigate anomalous results (Screening, ABO/D) • Need to interpret results in clinical context (ABO/D) • Security of automation / IT reduces human error (all BTLP schemes) Any interlaboratory comparison improves overall results!

42. EQA is part of a bigger picture Manufacturers Haemovigilance Guidelines EQA Quality Systems

43. Reveals problems in QS Offers peer comparison Gives reliable overview information Provides evidence based constructive advice Supportive Educative Seen as judgmental A competition! Replacement for other QA measures Guarantee of quality Effective EQA

44. Acknowledgements • All at UK NEQAS (BTLP) including • Scientific advisory panels for FMH, red cell genotyping and ABO titration • BTLP Steering Committee • All participating laboratories • ISTM / ISBT for the opportunity to be here today…. Further information: btlp@ukneqas.org Contact: jenny.white@whht.nhs.uk

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