Regarding the participation of the laboratories in each assessment, 95.5% participated in EQA 11, 92.1% in EQA 12, 97.7% in EQA 13, 88.8% in EQA 14, 95.6% in EQA 15, 93.3% in EQA 16, 97.8% in EQA 17, 93.5% in EQA 18, 92.5% in EQA 19, and 97.9% in EQA 20.
A percentage of 89.4 participating laboratories were awarded excellent/approved status in EQA 11, 85.0% in EQA 12, 89.8% in EQA 13, 80.0% in EQA 14, 87.0% in EQA 15, 93.0% in EQA 16, 86.0% in EQA 17, 89.7% in EQA 18, 84.8% in EQA 19, and 92.3% in EQA 20. Figure 2 shows the performance of laboratories in EQAs (EQA11–20) rated “approved” and “failed.” It can be noted that the percentage of approved and failed laboratories in the EQAs tend to follow a uniform pattern. Since 2011, approval has remained above 80% and the failure rate has never exceeded 15%.
Analysis of Table 3 reveals the identity of the laboratories with recurrent failures or low EQA participation. The laboratories that presented 3 or more situations that were not positive (ie, failed or did not participate) were selected for evaluation. Using these parameters, we identified 15 laboratories (of the total of 93) of which 12 were rated as “approved” interspersed with failures or nonparticipation. Three laboratories were considered more critical, since they presented consecutive failures and which had failed to participate consecutively in the last EQA round. This analysis enabled more specific strategies and actions to be structured for the most critical laboratories, with the possibility of carrying out more frequent follow-ups and retraining the professional staff.
4 Discussion and conclusions
This study describes the methodology used to evaluate the laboratories that comprise the CD4/CD8 T lymphocyte counting network of the Brazilian MoH. The evaluations respond to a need to ensure reliable results to the users of the National Unified Health System.
All the laboratory procedures were performed using the FACSCalibur 4-color equipment from the BD Bioscienses company, and the set of specific immunological reagents required for identifying cell surface markers, using flow cytometry, containing CD3/CD4/CD8/CD45 monoclonal antibodies. Other reagents such as controls, calibrators, and solutions were also provided by the supplier, as established in the contract, were also used in order to pursue the activities related to laboratory monitoring of the immunological defenses of HIV-infected patients, performing analyzes of peripheral blood samples for counting T lymphocytes and their subpopulations.
A comprehensive report is drawn up at the end of each evaluation process, containing information about the panel, its preparation, evaluation criteria, and the results. This is made available to all the laboratories in the Network and published on the MoH website. The confidentiality of the participants is respected. This methodology made it possible to evaluate and classify the laboratories belonging to the CD4/CD8 T lymphocyte network. Following the evaluation process all laboratories that perform satisfactorily receive a certificate of excellence or approval, according to their scores. Failed laboratories receive a technical visit from the company responsible for supplying the equipment and supplies. The company then issues a report of the visit, the operational, infrastructural, or equipment-related problems encountered, and provides other relevant information for the MoH to take corrective action to improve the quality of the laboratory network and the testing services for patients.
EQA for CD4 + T-lymphocyte count test is also established in several countries for more than 30 years, like the “The Quality Assessment and Standardization for Immunological Measures Relevant to HIV/AIDS” since 1997. The quality assessments worldwide also analyze interlaboratory variation like Brazil in order to obtain uniform results. Regarding sample type, the quality assessment programs usually use stabilized blood samples while in Brazil the samples are not stabilized. The blood samples are collected and shipped to the laboratories on the same day and the panels should arrive within 48 hours. Another difference is that Brazilian National Network for CD4 + T-lymphocyte Counting has the same equipment, calibrators, and the kits used for the procedure for all laboratories. When laboratories fail at the quality assessment, for all the experiences found, they also have specific actions to improve the quality as in Brazil.[10–12]
EQA contributes to reduce interlaboratory variation and also immunophenotyping error by promoting re-education of the technicians, routine adjustments, and equipment maintenance when necessary. In conclusion, EQA is very important to evaluate the performance of the laboratories, and to identify, monitor and resolve errors as quickly as possible.
The authors thank the Department of Surveillance, Prevention and Control of Sexually Transmitted Infections, HIV/AIDS and Viral Hepatitis, of the Secretariat for Health Surveillance of the Ministry of Health for providing the data of this study.
Conceptualization: A.S. Benzaken, A.F. Pires, I.M. Kohiyama, M.K.C. Brunialti, O.d.C.F. Júnior, P.C. Gaspar, R. Salomão.
Data curation: M.K.C. Brunialti.
Formal analysis: A.F. Pires, M.K.C. Brunialti.
Funding acquisition: A.S. Benzaken, A.F. Pires, J.B. Alonso Neto, M.L. Bazzo, M. Franchini, P.C. Gaspar.
Investigation: A.S. Benzaken, B.L.P. Wohlke, M.K.C. Brunialti, M. Franchini, O.d.C.F. Júnior, R. Salomão.
Methodology: B.L.P. Wohlke, M.L. Bazzo, M.K.C. Brunialti, R. Salomão.
Project administration: A.S. Benzaken, A.F. Pires, B.L.P. Wohlke, I.M. Kohiyama, J.B. Alonso Neto, M.L. Bazzo, M.K.C. Brunialti, M. Franchini, O.d.C.F. Júnior, P.C. Gaspar.
Resources: B.L.P. Wohlke, M.K.C. Brunialti.
Supervision: B.L.P. Wohlke.
Validation: M.K.C. Brunialti.
Writing – original draft: B.L.P. Wohlke, I.M. Kohiyama, M.K.C. Brunialti, P.C. Gaspar.
Writing – review & editing: A.S. Benzaken, A.F. Pires, B.L.P. Wohlke, I.M. Kohiyama, J.B. Alonso Neto, M.L. Bazzo, M.K.C. Brunialti, M. Franchini, O.d.C.F. Júnior, P.C. Gaspar, R. Salomão.
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Keywords:Copyright © 2018 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.
CD4+ T-lymphocyte; external quality assessment; quality; test performance