State of the art vs biological variability: Comparison on hematology parameters using Spanish EQAS data

Introduction It is important for clinical laboratories to maintain under control the possible sources of error in its analytical determinations. The objective of this work is to perform an analysis of the total error committed by laboratories using the data extracted from the Spanish External Quality Assessment Program in Hematology and to compare them with the specifications based on the biological variability proposed by the Ricós group. Material and Methods We analyzed a total of 3 89 000 results during the period 2015‐2016 from the following quantitative schemes of Spanish External Quality Assessment Program: complete blood count, blood coagulation tests, differential leukocyte count, reticulocytes, hemoglobin A2, antithrombin, factor VIII, protein C, and von Willebrand factor. It has been considered as an indicator of the current performance the value of total error that 90% of laboratories are able to achieve, taking into account 75% of their results. Results We found some magnitudes whose biological variability specifications are achievable by most of the laboratories for either minimum, desirable, or optimum criteria: white blood cells, red blood cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, platelets, fibrinogen, neutrophils, lymphocytes, eosinophils, von Willebrand factor, and protein C. However, current performance for mean corpuscular hemoglobin concentration and hemoglobin A2 only allows to meet the specifications based on the state of the art. Conclusion Our results reflect the feasibility of establishing specifications based on biological variability criteria or the state of the art, which may help to select the proper criteria for each parameter.