Use of Retained Samples for Quality Control of Hematology Analyzers in Low-Resource Laboratories. A Comparative Study Between Retained Samples and Controls

Background: Quality control is essential for verifying the performance of hematology analyzers (HAs).While internal quality control (IQC) materials are recommended, however their use is often limited in low-resource settings due to high costs, short shelf life and logistical challenges. This study is done to evaluate the utility and effectiveness of using retained patient samples for daily quality control in hematology analyzers and to compare their performance with standard IQC data in terms of accuracy and precision.Methods: Retained patient samples were tested in duplicate-once in the morning and again after overnight refrigerated storage (2–4°C). Results were compared with the corresponding IQC data in terms of calculating the coefficient of variation (CV%), standard deviation (SD) and performing statistical analysis for precision and reproducibility. Result: Minimum and maximum range in our study for retained samples for Hb (gm/dl) was 4.60-17.40, WBC (10x3mm/dl) 3.20-23.70, RBC (10x6mm/dl) 1.54-7.72 , Platelets (10x6mm/dl) 77-656. Correlation coefficient between 2 values of retained samples : Hb (0.997), Platelets (0.994), RBC (0.967), WBC (0.993). SD calculated on daily value difference was: Hb (0.15), Platelets (9.61), RBC (0.17), WBC (0.30). There was significant correlation between the IQC and retained sample data on Paired t-test (P < 0.05).Conclusion: P PAIR testing show significant correlation between retained samples and IQC and correlation coefficient is within limits. Retained human samples could be further studied and standardized for quality control use in resource-limited and remote settings where synthetic controls are cost-prohibitive.