Assessment and Control of Measurement Uncertainty in Complete Blood Count to Meet Acceptable Criteria in the Hematology Laboratory of Sakon Nakhon Hospital

Abstract

           This descriptive cross-sectional study was conducted to evaluate measurement uncertainty and establish tolerance limits for complete blood count (CBC) parameters. Data collection encompassed 40 internal quality control (IQC) values and external quality assessment (EQA) data from 2024. The analysis focused on five hematological parameters: white blood cell count (WBC), red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit (Hct), and platelet count (PLT).

            The primary objective of this investigation was to calculate measurement uncertainty values and establish acceptable tolerance limits for CBC analytical results utilizing IQC and EQA data from the hematology laboratory at Sakon Nakhon Hospital. The methodology involved computing combined uncertainty (Uc) and expanded uncertainty (U) following Nordtest guidelines, with subsequent comparison against Clinical Laboratory Improvement Amendments (CLIA) acceptance criteria.

            Analytical findings demonstrated that expanded uncertainty values for all assessed parameters remained within CLIA-acceptable thresholds: WBC ± 4.96%, RBC ± 0.66%, Hb ± 3.88%, Hct ± 4.04%, and PLT ± 9.82%. These results substantiate that quality control data derived from laboratory operations can be appropriately utilized for measurement uncertainty assessment. The findings indicate the feasibility of integrating measurement uncertainty evaluation into the laboratory's quality management system, thereby supporting future ISO 15189 accreditation requirements and enhancing analytical reliability in clinical hematology diagnostics.