Abstract Background Quality control, conducted through analyses or measurements, plays a crucial role in optimization and standardization of laboratory procedures, minimizing time and waste, and enhancing the reliability of inputs and products. During laboratory tests, various factors must be controlled and monitored to ensure the accuracy of results. The Coefficient of Variation (CV) is a statistical measure presented as a percentage that expresses the dispersion of data relative to the mean, considering the standard deviation (SD). Laboratory internal control involves procedures and guidelines to ensure quality, precision, and efficiency while minimizing errors and risks. This study aimed to highlight the importance of daily monitoring of internal quality controls to ensure the suitable performance of equipment in a clinical laboratory setting. Methods An analysis of performance was conducted based on the CV data acquired monthly and on the repetition index of the commercial controls processed on the BNII equipment (Siemens), which analyzes a total of 17 analytes. The analysis lasted for 9 months and was carried out in 3 phases: 1) Pre-implementation period (April to June 2024); 2) Implementation period (July to September 2024) and 3) Post-implementation period (October to December 2024). The monthly CV was calculated considering the SD of the results from various levels of internal control, which were validated and measured daily. The repetition index indicates the number of control repetitions required until validation is achieved. In addition, CV data from analytes that presented results out of the expected range in at least two consecutive months within a 3-month period (recurring results), were also analyzed. Results The findings from the pre-implementation phase showed that 60% of analytes presented a monthly CV according to the standard range. In the second phase corrective actions were implemented, and 70% of the analytes obtained CV values within the expected range. Furthermore, during the post-implementation period, the number of analytes with CVs within the specified limits increased by 19%, reaching 79%, compared to the pre-implementation phase. Regarding the repetition index analysis, results from the first phase showed that controls were repeated 14% of cases, which increased to 18% in the second phase due to the corrective actions applied. In the final phase, an improvement was observed, with the repetition index reduced to 9%. Finally, the analysis of recurring results showed that in the first phase, 11 analytes presented CV values out of the standard. By the end of the third period, only 2 analytes exhibited recurring results related to inadequate CV. Conclusion Daily monitoring of the CV values of internal controls allowed implementation corrective actions that resulted in a significant improvement in the results of monthly CV, with an increase in the percentage of analytes with CV within the expected range. Consequently, the repetition of control processing and non-validated tests decreased. These findings highlight the importance of good professional practices and continuous monitoring of analytical performance to ensure the proper functioning of quality processes leading excellence in the results provided to patients.
Ramadan-Boscolo et al. (Wed,) studied this question.