Estimation of Alert and Change Limits of Haematological Quantities and its Application in the Plausibility Control

INTRODUCTION: In the process of quality assurance of the measured values of the clinical laboratory, one of the purposes is to perform the validation of patients’ measured values in the most objective way. This validation process is called plausibility control which may be defined as the set of procedures used to decide if a patient’s measured value is valid according to established clinical and biological criteria. The aim of this study is to propose a model to estimate alert and change limits of measured values of the blood cell count, to be applied to detect doubtful patients’ measured values. METHODS: Some alert and change limits were estimated from the emergency laboratory database of the year 2010 using different percentiles. A verification of the suitability of the proposed model was also performed. RESULTS: Most of the fractions of the measured values excluded by the alert and change limits were according to the theoretical expected. The overall fraction of the number of doubtful clinical laboratory reports ranged between 0.6 and 47.6 %. CONCLUSIONS: The proposed model helps, improves and standardizes the process of detection of doubtful measured values since they are produced objectively. These limits can also be configured in a laboratory information system letting the clinical laboratory professional staff to save time and efforts.