Timóteo, Maria HelenaTavares, Ana SofiaPereira, Paulo2026-03-112026-03-112026-04Timóteo MH, Tavares AS, Pereira P. Emerging practices in the estimation of hemoglobin measurement uncertainty in blood establishments. Transfus Apher Sci. 2026;65(2):104401.1473-0502http://hdl.handle.net/10400.21/22715Measurement uncertainty (MU) is increasingly recognized as a critical analytical parameter within ISO and European regulatory frameworks. In transfusion laboratories, where hemoglobin testing determines donor eligibility and informs transfusion decisions, MU directly impacts patient and donor safety. This study applies ISO/TS 20914:2019 to estimate MU in hemoglobin testing using the cyanmethemoglobin method in EDTA-K3 venous blood. A parametric simulation model informed by EFLM biological variation data was used to evaluate three scenarios: (1) within-laboratory imprecision, (2) addition of calibrator uncertainty, and (3) incorporation of significant bias uncertainty. All scenarios met desirable (2.7 %) and minimum (4.1 %) performance targets for allowable uncertainty. These findings reinforce the integration of MU estimation as a European and ISO-endorsed best practice in transfusion laboratory medicine. This approach supports traceable, risk-informed decision-making, aligning transfusion services with ISO 15189:2022 requirements.engBiological variationDonor screeningHemoglobin testingISO 15189ISO/TS 20914IVDRMeasurement uncertaintyTransfusion safetyjournal article10.1016/j.transci.2026.104401