RESUMO
INTRODUCTION: The external quality assessment (EQA) scheme is particularly important for laboratory performance evaluation. Peripheral blood smears are necessary to identify morphological features, and the procedure for preparing such smears must be robust to meet the ISO 15189 standard. Although blood smear preparation is a routine activity in medical laboratories, an appropriate procedure for preparing a series of blood smears with high homogeneity and durable stability for EQA purposes has not yet been published elsewhere. For this reason, a robust procedure was developed and validated in this study. METHODS: Various factors affecting blood smear preparation, such as the amount of time collected blood samples are stored before fixation, suitable reagents, and specification parameters for each step, including fixation, staining, and timing of the staining steps, were studied. Each experiment was evaluated based on homogeneity and stability characteristics. RESULTS: Whole blood mixed with EDTA anticoagulant was used to make the blood smears. Samples were fixed with pure anhydrous alcohol and stained in Coplin jars using the Wright-Giemsa method. CONCLUSION: The homogeneity and stability of two lots of smears suitable for EQA purposes was confirmed based on intact morphology of the smears for more than 8 months at room temperature.
RESUMO
BACKGROUND: External quality assessment (EQA) provides evidence of reliable, accurate, and precise results for customers using the diagnostic test for Toxocara canis. Objective. To establish a procedure for producing standard Toxocara canis serum samples for serodiagnostic testing in EQA. METHODS: The collected serum samples to contain anti-Toxocara canis serum samples for serodiagnostic testing in EQA. F-test and a T-test were applied to evaluate their homogeneity and stability. RESULTS: Among eleven samples positive by ELISA, ten of them were confirmed via Western blotting by positive reaction with 5 specific Toxocara canis serum samples for serodiagnostic testing in EQA. Toxocara canis serum samples for serodiagnostic testing in EQA. p > 0.05). Samples produced by both methods were stable for 7 days at 30°C (p > 0.05). Samples produced by both methods were stable for 7 days at 30°C (. CONCLUSION: Specific serodiagnosis samples of anti-Toxocara canis antibodies for EQA could be produced that possessed homogeneity and stability lasting for 3 months and 6 months by the freeze-drying and freezing methods, respectively. At 30°C, the samples produced by both methods were stable for 7 days, suitable for delivery to remote laboratories.Toxocara canis serum samples for serodiagnostic testing in EQA.
