Annual Report April March 2015

Transcription

1 Annual Report April March 2015 Laboratory Service: Scottish Toxoplasma Reference Laboratory Author: Drs E Watson/R Evans Date : 19 th June 2015 Report due: 19 th June 2015 Table of Contents 1 Summary with key points for consideration Public Health impact Public Health benefits relating to the service delivered, including changes in clinical practise, activity underpinning national action plans, participate in national surveillance and support in outbreaks and incidents Public Health benefits relating to other activities, include items such as membership of national and regional committees, guideline writing groups New service developments Activity data Contracted activity Activity by NHS Board Total number of samples received for all organisms by NHS Board (for equity purposes) Quality assurance Turnaround times Summary of audit activity User engagement and feedback, including user audits Incidents and complaints Accreditation schemes Research and development (R&D) Education and training a) Internal staff training b) Individual placements c) External training Staffing Ongoing/ future developments Finance Appendices Appendix A Appendix B Appendix C Glossary... 15

2 1 Summary with key points for consideration Public Health impact The service provided by the STRL indicates that the epidemiology of toxoplasma is changing in Scotland. Cases of congenital toxoplasmosis are exemplar of the cost of toxoplasma to Scotland and the need for clinicians to be aware of this disease. The identification of particular ethnic groups (Eastern European) with a higher seroprevalence of toxoplasma to the majority population in the NHS Highland region has important public health implications with a larger national study indicated. The development of novel antibody tests for the detection of sporozoites in the US has provided more accurate information about the transmission of toxoplasma infection with an indication that transmission by tissue cyst may be the main source of infection but this, too, needs validation with a larger study. The results of studies such as these will address the changing epidemiology of toxoplasmosis and allow for improved, targeted, evidence-based, public health information on the prevention of toxoplasma infection in Scotland. New service developments Development of Mycoplasma free cell culture system for production of toxoplasma tachyzoites for the gold standard dye test. Audit of IgG avidity immunoblot and EIA methods for the determination of the timing of infection. Activity and quality assurance Overall testing activity is lower than previous year although the number of cases of current toxoplasma infection diagnosed has increased. The introduction of new methods and techniques has provided a more robust diagnostic service. The STRL has performed well in external and internal quality assurance schemes. Research and development (R&D) Development of diagnostic testing protocol for the diagnosis of ocular toxoplasmosis. Identification of Toxoplasma gondii strains circulating in Scotland. Education and training Internal training is on-going with the change in the staffing structure introduced last year. Continuing training of HST trainees. Changes in staffing This is the first full year that the reference service has operated with the new complement of staffing. The service has benefited from its experienced and expert staffing in key areas to allow the transition to proceed smoothly. Ongoing/ future developments (emerging issues and service needs) There is a greater need for a more accurate method of diagnosing ocular toxoplasmosis and this is one of the R&D aims for this year. Page 2 of 15

3 2 Public Health impact 2.1 Public Health benefits relating to the service delivered Toxoplasmosis is being increasingly recognized as a serious zoonotic infection of man. Studies from the US, Holland and Greece have indicated that toxoplasmosis is one of the top three to five foodborne infections in terms of human and financial cost. In 2011 these concerns resulted in a consultation document being produced by the Food Services Agency (FSA) on behalf of the government to assess the risk of toxoplasmosis in the UK. This document highlighted significant gaps in our current knowledge of this infection. The Scottish Toxoplasma Reference Laboratory (STRL) provides a diagnostic service for Scotland and Northern Ireland and recent results suggest the epidemiology of toxoplasma infection is changing and there is cause for concern. When the clinical information and laboratory results for patients referred in and were compared there were more cases of current infection identified in and there were more current infections in women of childbearing age. In we identified three babies with severe congenital toxoplasmosis. Cases of severe congenital toxoplasmosis are rarely seen and three cases in one year are unprecedented. These data demonstrated the need for up to date information if toxoplasma infection is to be diagnosed and correctly managed in the future. Prevalence data from a study testing antenatal sera carried out by STRL 30 years ago indicated that the prevalence of toxoplasmosis was 15% in Scottish women. No recent studies have been undertaken and this was one of the knowledge gaps highlighted in the consultation document from the FSA. We have compared the current prevalence rate with these historic data to identify whether there has been a change in the epidemiology of toxoplasma infection in Scotland. The seroprevalence data from ante-natal women for in Highland produced variable rates for the different ethnic groups. The majority of cases were of UK/white Scottish/W Europe origin (72%) with a seroprevalence rate of 7.6%. The higher rates were found in Eastern Europe (32.4%), other (22.7%), other white group (20%) and Asia (17.8%) ethnic groups. These results have important public health implications, not only for ante-natal women but for patients with some form of immunocompromise who can be at risk of reactivated infection. The higher the seroprevalence rate the greater the potential for reactivation and clinicians need to be aware of these epidemiological differences within ethnic groups. A collaborative study with colleagues in America aimed to identify the source of toxoplasma infection in ten women with current infection. The current method of STRL to identify the possible source of toxoplasma infection has relied on questionnaire data from patients with current infection. Often no risk factors are stated. This small study suggests that only 10% of toxoplasma infections in Scottish patients would be due to ingestion of oocysts. Although these results need to be validated in a larger study they suggest, in Scotland, the more important route of transmission may be via tissue cysts and the ingestion of undercooked or raw meat. The results of the service provided by the STRL indicate that the epidemiology of toxoplasma is changing in Scotland. Cases of congenital toxoplasmosis are exemplar of the cost of toxoplasma to Scotland and the need for clinicians to be aware of this disease. The identification of particular ethnic groups with a higher seroprevalence of toxoplasma to the majority population in the NHS Highland region has important public health implications with a larger national study indicated. The development of novel antibody tests for the detection of sporozoites in the US has provided more accurate information about the transmission of toxoplasma infection but this, too, needs validation with a larger study. The results of studies such as these will address the Page 3 of 15

4 changing epidemiology of toxoplasmosis and allow for improved, targeted, evidencebased, public health information on the prevention of toxoplasma infection in Scotland. 2.2 Public Health benefits relating to other activities Dr Emma Watson and Dr Roger Evans attend the Scottish Clinical Virology Consultants Group at quarterly meetings who provide expert opinion to various Medical Microbiology organisations within Scotland and the UK. 3 New service developments STRL continues to develop a cell culture system that is devoid of Mycoplasma contamination. This has involved intensive, continuous training of staff in clean cell culture techniques in the preparation of cell culture and media. A Mycoplasma PCR protocol has been devised that monitors the levels of Mycoplasma contamination within the cell culture system. The introduction of the Mikrogen Immunoblotting assay has been important in the determination of the timing of toxoplasma infection, particularly in pregnant women. The purchase of the scanner from NSD capital equipment funds (< 5 000) to accurately read the immunoblots has greatly improved this service and has allowed for a wider range of qualified staff to run this assay routinely. The performance and role of the immunoblot assay is currently being audited with the Abbott Architect IgG avidity assay. The in-house IgG avidity assay has been replaced by the Abbott Architect IgG Avidity assay. An audit was carried out and the results are presented in Appendix A. 4 Activity data 4.1 Contracted activity Method Name of test/investigation Contracted number Page 4 of 15 Actual number ELISA IgG DYE TEST ARCHITECT IgM ISAGA IgM IgG AVIDITY EIA IMMUNOBLOTTING PCR ISOLATION (BY CELL CULTURE) TOTAL Number Positive Tests Comments on contracted activity: The figures are lower than the contracted number as those samples received for toxoplasma screening from patients in Highland Health Board have been excluded as discussed at the meeting on the 23 rd March The total number of tests excluded is 286 (143 ELISA IgG, 143 dye test). The number of IgG avidity EIA tests is significantly lower than expected because of difficulties with inter-run variation with the in-house assay. This assay has been superseded by the Abbott Architect IgG avidity assay. This platform was being introduced to the department for other assays and was convenient and cost effective to use for the

5 Toxoplasma IgG avidity assay. However, it has the drawback of requiring a dead volume of 280µl of serum which restricts the number of referred samples that can be tested. There has been a slight increase in the number of immunoblotting tests because of its usefulness in determining the timing of infection. This has proven to be very helpful in diagnosing patients and the use of the scanner has improved the accuracy and consistency of the reading of these results. We are currently evaluating the avidity IgG EIA and the immunoblot avidity IgG tests. A total of 204 tests were performed on 80 samples from Northern Ireland (ELISA IgG 69, dye test 78, Architect IgM 33, ISAGA IgM 5 and PCR 20). The N Ireland samples are 8.1% of the contracted activity of STRL and provide an income of Activity by NHS Board Toxoplasma EIA IgG Test / Investigation: NHS Board Current Year Previous Year Ayrshire & Arran 10 Borders 1 Dumfries & Galloway 34 Fife 14 Forth Valley 0 Grampian 40 Greater Glasgow & 139 Clyde Highland 116 Lanarkshire 124 Lothian 299 Orkney 0 Shetland 0 Tayside 37 Western Isles 2 Comments on activity by NHS Board: The figures for the previous year are not available. It is suspected that the figures of zero for Forth Valley and Orkney/Shetland will be due to the referral of samples to the WoSSVC and the Aberdeen laboratories respectively first before referral to the STRL. Toxoplasma dye test Test / Investigation: NHS Board Current Year Previous Year Ayrshire & Arran 11 Borders 1 Dumfries & Galloway 40 Fife 15 Forth Valley 0 Grampian 48 Greater Glasgow & 153 Clyde Highland 137 Lanarkshire 140 Lothian 310 Orkney 0 Shetland 0 Page 5 of 15

6 Tayside 40 Western Isles 2 Comments on activity by NHS Board: See above. Toxoplasma Architect IgM Test / Investigation: NHS Board Current Year Previous Year Ayrshire & Arran 9 Borders 0 Dumfries & Galloway 10 Fife 7 Forth Valley 0 Grampian 17 Greater Glasgow & 77 Clyde Highland 80 Lanarkshire 24 Lothian 247 Orkney 0 Shetland 0 Tayside 17 Western Isles 1 Comments on activity by NHS Board: Detection of IgM is usually an indication of current infection. For this period Lothian detected 21 cases of toxoplasmosis in contrast to the second largest referral centre, Greater Glasgow and Clyde, which had three cases for the same period. This is an interesting observation which had been noted over many years. The introduction of referral criteria by Greater Glasgow and Clyde has not altered the discrepancy between the two largest population centres in Scotland. Toxoplasma ISAGA IgM Test / Investigation: NHS Board Current Year Previous Year Ayrshire & Arran 0 Borders 0 Dumfries & Galloway 0 Fife 0 Forth Valley 0 Grampian 3 Greater Glasgow & 2 Clyde Highland 15 Lanarkshire 3 Lothian 7 Orkney 0 Shetland 0 Tayside 1 Western Isles 0 Comments on activity by NHS Board: Page 6 of 15

7 The Highland figures are higher than the other Health Board areas as this test is used for the UK NEQAS scheme. Samples requiring testing by ISAGA IgM assay are sent from the major referral centres and as the test is used for patients who are likely to be at these tertiary centres (HIV/AIDS, transplant patients, congenital infection). Toxoplasma IgG avidity Test / Investigation: NHS Board Current Year Previous Year Ayrshire & Arran 0 Borders 0 Dumfries & Galloway 0 Fife 0 Forth Valley 0 Grampian 0 Greater Glasgow & 1 Clyde Highland 6 Lanarkshire 0 Lothian 5 Orkney 0 Shetland 0 Tayside 2 Western Isles 0 Comments on activity by NHS Board: Numbers are lower for this test as discussed in section 4.1. Again the figures are elevated for the Highland Health Board area because of the UK NEQAS samples that are tested. Toxoplasma Immunoblot Test / Investigation: NHS Board Current Year Previous Year Ayrshire & Arran 1 Borders 0 Dumfries & Galloway 0 Fife 0 Forth Valley 0 Grampian 2 Greater Glasgow & 1 Clyde Highland 1 Lanarkshire Lothian 7 Orkney 0 Shetland 0 Tayside 3 Western Isles 0 Comments on activity by NHS Board: The immunoblot has been an important addition to the repertoire of tests and the numbers are indicative of those centres that have diagnosed current toxoplasma infection in patients. Page 7 of 15

8 4.3 Total number of samples received for all organisms by NHS Board (for equity purposes) NHS Board Current Year Ayrshire & Arran 10 Borders 1 Dumfries & Galloway 34 Fife 14 Forth Valley 0 Grampian 40 Greater Glasgow & Clyde 139 Highland 116 Lanarkshire 124 Lothian 299 Orkney 0 Shetland 0 Tayside 37 Western Isles 2 5 Quality assurance 5.1 Turnaround times Actual number Test/Investigation of tests SLA turnaround time Turnaround time (mean) Turnaround time (range) % Tests meeting target ELISA IgG DYE TEST ARCHITECT IgM ISAGA IgM IgG AVIDITY EIA IMMUNOBLOTTING PCR ISOLATION (BY CELL CULTURE) 0 7 Not applicable (NA) Urgent samples 0 2 NA NA NA Comments on turnaround times: Overall the turnaround times were excellent with 5 of the 7 tests meeting the target. However, two samples were tested at 10 and 20 days post receipt for IgG avidity and Immunoblotting respectively. The report was validated and sent out of the STRL before 7 days for these samples. The tests were done later to assess their performance with the available clinical information and existing test results and did not affect the report. NA NA 5.2 Summary of audit activity There has been a change in the audit schedule within all laboratory departments at Raigmore hospital. This is indicated by the fewer number of audits performed this year. Page 8 of 15

9 However, this meets CPA standards and all aspects of the reference laboratory will be assessed on a rotational basis between CPA inspections Horizontal audit: Not performed Vertical audit: not performed Examination audit: not performed Other audits Abbott Architect IgG avidity audit Internal Quality Assurance Four samples: recycled in four distributions of 1 sample 4 tests: EIA IgG (2), Dye test (2) and PCR (2) There were no differences in test selection, results or interpretation UK NEQAS Toxoplasma serology 12 samples, 4 distributions of 3 samples with pre- and post distribution testing. 92 tests: EIA IgG (24), Dye test (24), EIA IgM (24), Avidity (8), ISAGA IgM (12) Success rate: 100% National Toxoplasma Reference Unit Serology 10 samples, 1 distribution of 10 samples. EIA IgG (10), Dye test (10), EIA IgM (10), IgG Avidity EIA (2) Success rate: 100% National Toxoplasma Reference Unit PCR 4 samples, 1 distribution of 4 samples Success rate: 75% (1 toxoplasma equivalent sample not detected by Raigmore method. There has been a change in the sample preparation method and so the protocol is being investigated and the results will be written up as an audit) Audit with users Questionnaires are sent to collect information on patients with current toxoplasma infection and ocular toxoplasmosis. The annual rate of return for current infection is 20/39 (52%) for Scotland and Northern Ireland. The rate of return for the ocular questionnaire is 18/33 (55%). 5.3 User engagement and feedback, including user audits There has been engagement with users on an informal basis particularly with respect to lost reports. These issues were dealt with as they were raised; some of the samples had not been received at the laboratories and some reports had been sent but not arrived at the referring laboratory. There was a period when the office responsible for posting reports had been staffed by temporary staff and may have accounted for some of the missing reports. However, a permanent member of staff is in place and the system is functioning satisfactorily. A letter of support for the STRL from the laboratory Consultants who use the service in Scotland was sent to Dr Kate Harley, HPS. The letter is appended. 5.4 Incidents and complaints None. Page 9 of 15

10 5.5 Accreditation schemes Name of scheme CPA UK accreditation Current status (e.g. full accreditation) Full accreditation (0423) Date of last visit and type April 2015, interim Date of next visit and type April 2017, UKAS inspection 6 Research and development (R&D) Research projects (source and funded amount) and collaborations Nuffield Project. Ocular toxoplasmosis. Jamie Stewart. Original articles (accepted) Padley DJ, Heath AB, Chiodini PL, Guy E, Evans R and the Collaborative Study Group (2014). An international collaborative study to establish a WHO internal standard for Toxoplasma gondii DNA nucleic acid amplification technology assays. World Health Organisation, WHO/BS/ Presentations/ posters ECCMID May Poster. Changing epidemiology of toxoplasmosis in pregnant women from the Highlands region of Scotland SDVG 23 May Presentation. The changing face of toxoplasmosis SDVG 12 November Presentation. Cases of ocular toxoplasmosis Dr Jonathan Foulds Ophthalmology Department, Raigmore Hospital 14 November Presentation. Diagnosis of ocular toxoplasmosis and other infectious eye diseases Microbiology Department, Raigmore Hospital 9 December Presentation. Toxoplasma case studies. Other publications (e.g. UK reports) None 7 Education and training a) Internal staff training Type of training Clinical training Diagnostics Diagnostics Numbers attending 2, Consultant and Clinical Scientist 2, BMS 4, MTO/MLA Page 10 of 15

11 b) Individual placements Base place of Duration of Visitor Grade Speciality work placement Jamie Stewart Student None School Six weeks c) External training E.g. lectures, tutorials off site, open day etc. Type of training Topic Numbers attending Lecture Diagnosis of ocular 12 toxoplasmosis and other infectious eye diseases Lecture Toxoplasma case 20 studies. 8 Staffing This is the first full year that the reference service has operated with the new complement of staffing. The service has benefited from its experienced and expert staffing in key areas to allow the transition to proceed smoothly. The service has changed markedly over the last two years and staff have responded well to this challenge. There are currently no retention and recruitment difficulties foreseen. An element of succession planning in training has been introduced with the anticipated retirement of a senior member of staff in the next two years. 9 Ongoing/ future developments Currently the source of accessory factor, an important reagent in the toxoplasma dye test, is provided on an ad hoc basis from the SNBTS. SNBTS provide large volumes ( ml) of serum from donors that are assessed and validated for use by the STRL in the dye test. Current stocks are adequate for the next two years and it is anticipated that this ad hoc agreement should be formalised. This process has commenced and should be completed in the next six months. An ongoing audit is being coordinated by UK NEQAS Parasitology to assess the usefulness of IgG avidity in the diagnosis of toxoplasmosis. STRL is part of the collaborative group. UK NEQAS is also introducing a pilot study for the detection of toxoplasma DNA by molecular methods in cooperation with STRL. Questionnaires have been sent to users and STRL are waiting for the results to be circulated. Improvement to the diagnosis of ocular toxoplasmosis is on-going. The use of the Goldman Witmar coefficient (GWC), immunoblot and PCR in combination provides the most sensitive and specific diagnostic algorithm for ocular toxoplasmosis. Methodologies to determine the GWC using small volumes of ocular fluid are being investigated. It is hoped to undertake a collaborative project to identify the strains of Toxoplasma gondii circulating within Scotland from historical samples held by the STRL. Discussions with veterinary colleagues will be had as to how this could be progressed. Page 11 of 15

12 10 Finance EXPENDITURE Current year Staffing WTE Total salaries Total supplies n/a 25,960 Other non-pay costs n/a 0 Capital charges n/a 0 Income from tests n/a TOTAL EXPENDITURE n/a Although the total supplies cost was there were three items of expenditure that are non-recurring costs. These were single payments for specific items of the new cell culture system and reagent and assay costs that are now obsolete. The total non-recurring cost was Appendices Appendix A Architect IgG avidity audit 1. Background An in-house toxoplasma IgG avidity EIA has been used for a number of years as part of the testing protocol for the Scottish Toxoplasma Reference Laboratory. In the last year it had been noticed that the performance of this test had been erratic and inconsistent. Collaborative work with UK NEQAS had raised questions about the value of IgG avidity testing for toxoplasmosis and this is being investigated by UK NEQAS. However, during this period the Abbott Architect analyser was being introduced into the department for viral serology testing and it seemed to be an appropriate time to evaluate their toxoplasma IgG avidity as a replacement for the inhouse assay. Additionally the introduction of ISO standards and the change in staff mix within the department lent itself to introducing a CE marked commercial IgG avidity assay. 2. Kind of Audit This is a comparative assessment of performance of the Abbott Architect platform alongside current testing to ensure performance prior to introduction in the laboratory. 3. Criteria of Measurement Panels of samples were obtained from the Scottish Toxoplasma Reference Laboratory. Samples were tested using the Architect alongside the current in-house assay and the range of tests available at the Scottish Toxoplasma Reference Laboratory. The results were tabulated to assess the system for suitability for use. 4. Method of Enquiry Patient serum and plasma samples were used to create panels to test in parallel with the in-house avidity test. These included a range of high, low and intermediate avidity samples. EQA panels were also tested in parallel. 5. Audit Team and Resources R Evans, N Spence, R Milner. Abbott provided the test assays. 6. Comparison with Standards Thirty-one samples were tested. Five samples were tested in multiple runs. Page 12 of 15

13 A summary of results are shown in tables 1-4 Table 1. Results of the Architect and in-house IgG avidity assays with routine clinical samples Architect Clinical details Number Avidity result Architect Avidity (%) In-house Avidity result 1 High 67.6 High Probable past infection 2 Low 5.1 Low Ocular toxoplasmosis (500iu/ml) 3 High 88.4 High Past infection 4 High 85.7 Borderline Probable past infection (persisting IgM 5 Low 28.3 Low Current infection 6 High 74.8 Low Past infection (persisting IgM) 7 Low 5.2 High Recent infection (1 year onset) 8 High 89.5 Low Past infection 9 High 60.8 Borderline Possible current infection (DT 125iu/ml, IgM positive no onset stated 10 Low 5.1 High EQA, avidity high 11 Low 39.1 Borderline Past infection There was agreement in 4/11 (36%) between the two assays (nos. 1, 2, 3, 5), the results of which were consistent with the clinical details. 3/11 (27%) gave more consistent results with the clinical details with the Architect assay (nos. 4, 6, 8). 3/11 (27%) gave more consistent results with the clinical details with the in-house avidity assay (nos. 7, 9, 10) and 1/11 (10%) were inconsistent with both assays with the clinical details (no. 11). However, sample no. 9 was very near the cut-off of borderline and high (60.8%) which is 60%. Table 2. Results of the Architect IgG avidity assay with EQA samples Patients Date tested Result Avidity Onset (d) 12 13/01/ Low NK 13 (repeat of 12) 16/01/ High NK Clinical details NEQAS IgM negative, avidity high NEQAS IgM negative, avidity high NEQAS IgM positive, avidity low 14 15/01/ Low NK 15 22/01/ High NK EQA Swansea 16 22/01/2015 Fail Insufficient NK EQA Swansea 3/5 (80%) of the avidity results were the same as the EQA results (nos. 13, 14, 15). One sample was incorrect (no.12) but a second aliquot of this sample (no.13) was correct. It is uncertain whether this was an error in the sample preparation or inconsistency between runs. For one sample there was insufficient volume to run the assay. Page 13 of 15

14 Table 3. Results of the Architect IgG avidity with samples of past infection and IQA control samples tested multiple times Controls Date tested Result Avidity Expected result 17 13/01/ High High 17 15/01/ High High 17 16/01/ Low High 17 22/01/ Greyzone High 18 13/01/ High High 18 15/01/ High High 18 16/01/ High High 18 22/01/ High High 19 13/01/ High High 19 15/01/ High High 19 16/01/ High High 19 22/01/ High High 20 15/01/ Low High 20 16/01/ Low High 20 22/01/ Greyzone High 21 15/01/ Low High 21 16/01/ Low High 21 22/01/ Low High 22 22/01/ Low Low 23 22/01/ Low Low 6/7 (86%) samples gave the correct avidity results (nos. 17, 18, 19, 21, 22, 23). One sample (no. 20) was consistently incorrect giving two low and one greyzone avidity results for a high avidity control. The low values were very close to the greyzone range (49.99/49.49 versus 50%). Nevertheless these results should have been >60%. There was significant between-run variation for 2/5 (40%) of the samples (nos. 17, range % and 20, range %). Table 4. Results of the Architect IgG avidity of 8 well characterised samples. Patients Date tested Result Avidity Onset (d) Clinical details 24 13/01/ Low 13 Lymphadenopathy 25 13/01/ Low 35 Lymphadenopathy 26 13/01/2015 Fail Insufficient 58 Lymphadenopathy 27 13/01/ Low 42 Lymphadenopathy 28 16/01/ Low 21 Lymphadenopathy 29 13/01/ Low 23 Lymphadenopathy night sweats Sore throat, 30 13/01/2015 Fail Insufficient /01/ Low Not known swollen neck Uveitis WB avidity 6+ months post infection Results were available for six of the 8 samples. 5/6 (83%) of the samples were consistent with the clinical information (nos. 24, 25, 27, 28, 29). One sample was considered low avidity although onset was likely to have been greater than six months (no. 31). Two samples failed because of insufficient serum to test (nos. 26 and 30). Page 14 of 15

15 Overall for samples tested by the Architect IgG avidity assay 21/31 (68%) of samples gave correct results and 7/31 (23%) were inconsistent with the results of other assays or the clinical details. Three samples (9%) had insufficient serum volume for testing. 7. Review of Audit The performance of the Architect IgG Avidity assay was not entirely satisfactory. Since only 68% of samples gave a correct result this assay cannot be used as a stand alone assay and must be interpreted with the results of the other assays performed at the STRL. However, the assay is part of the testing protocol for the NEQAS scheme and STRL is required to provide these results as the NEQAS scheme are assessing avidity assays for toxoplasma testing. The between-run variation should be monitored although this may have been due to the lack of familiarity with the assay on the Architect platform. This problem does not seem to have been observed since the staff have become more familiar with the assay. The failure of testing in 9% of samples is disappointing and should be monitored. These failures were due to the lack of volume of serum (280µl dead volume) and this will be an issue for referred samples which are received as usually there is µl serum sent. 8. Implementing Change The Architect IgG avidity assay should be used and assessed in parallel with the other assays performed at the STRL. The in-house assay should be discontinued and this has happened since January Monitoring of this assay will give us more information about its performance with the other assays and the results should be reviewed in six months end of 2015). There should be no change to the Users manual yet regarding the volume of serum required for testing until the review is completed. At this point a decision should be made about which may be the most suitable assay(s) to use. Appendix B None Appendix C None 12 Glossary EIA = Enzyme Immunoassay ELISA = Enzyme Linked Immunosorbent Assay FSA = Food Services Agency NA = Not applicable SNBTS = Scottish National Blood Transfusion Service STRL = Scottish Toxoplasma Reference Laboratory WOSSVC = West of Scotland Specialist Virology Centre Page 15 of 15