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Understanding commutability: important quality requirement for clinical laboratories

INTRODUCTION: Few Brazilian laboratories evaluate the commutability of test results, probably due to the lack of procedure expertise as well as the neglected importance of its assessment. OBJECTIVE: The aim of this study was to evaluate the commutability of hematological test results performed with three automated analyzers at the laboratory of a public university hospital in Belo Horizonte, MG, Brazil, proposing a practical, simple, and feasible procedure to be applied in clinical laboratories. MATERIAL AND METHODS: Samples were selected in order to obtain hematologic values for therapeutic decision levels. Six samples were processed in duplicate in three analyzers daily during a four-day period amounting to a total of 48 replicates in each instrument. The correlation between the results of 10 hematologic parameters obtained with test instruments and the reference instrument was assessed. Systematic and total errors were estimated and criteria for acceptable performance were based on the biological variation specifications. RESULTS: The correlation coefficient (r) between test instruments and reference instrument results was > 0.975. Systematic (mean) and total errors met the required quality specifications when compared with reference instruments. Discussion: Commutability is an important process of quality management in clinical laboratories and it ensures the comparability of test results carried out with different procedures. CONCLUSION: Through a practical, simple, and internationally standardized procedure, this study showed that test results from the evaluated instruments were equivalent, which allows their use in patient monitoring.

Blood cell count; Laboratory techniques and procedures; Quality control; Accreditation; Health management; Commutability


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