[Pneumatic tube system for transport of laboratory samples: preanalytical aspects]. / Preanalitikai szempontok pneumatikus csopostával szállított laboratóriumi minták esetén.

INTRODUCTION: A considerable proportion of laboratory errors occurs in the preanalytical phase. AIM: The aims of the authors were to study preanalytical errors in routine and emergency laboratory diagnostics in a regional clinical laboratory and evaluate the effect of the pneumatic tube system on turnaround time and laboratory results. METHOD: The ratio of preanalytical errors and reasons of test rejection were analysed. In addition, the effects of pneumatic tube and manual transport on the occurrence of hemolysis and platelet activation were compared. RESULTS: Using the pneumatic tube transport system, preanalytical error was below 1%. The main causes of test rejection were haemolysis in case of serum samples, and clot formation and citrate excess in anticoagulated samples. The pneumatic tube transport resulted in significantly faster sample transport, more equalized sample arrival and processing, hence the turnaround time became shorter both for routine and emergency tests. CONCLUSIONS: Autovalidation and proper control of preanalytical errors are essential for rapid and reliable laboratory service supported by the pneumatic tube system for sample transport.

["Turnaround time": a new parameter for the characterization of the overall efficacy of laboratory diagnostic processes]. / "Turnaround time": a laboratóriumi eredménykiadás hatékonyságának új paramétere.

INTRODUCTION: The authors developed a special computer-aided routine in their laboratory for the calculation of "turnaround time" which parameter is suitable for the characterization of the overall efficacy of laboratory diagnostic processes. The turnaround time is defined as the interval between the arrival time of a sample in the laboratory and the time of clinical validation. It characterizes the efficacy of the result generation process very well, and therefore, is considered as an important parameter of laboratory quality control. METHODS: In their present study the authors analyzed the data of the urgent (stat), routine and special laboratory tests of 6 months and presented the median, 5- and 95-percentile values of turnaround time. Beside this, they calculated the rate of "outliers": the number of tests having a longer turnaround time value, than the defined maximal turnaround time (stat 1 hour, routine 4 hours, special 2-14 days). RESULTS: The median turnaround time values were 9-70 minutes for the stat tests and 33-190 minutes for the routine analytes. In case of special tests, the results were much more heterogeneous, in general non-automated hemostasis and immunochemistry assays, with low sample numbers had longer turnaround time values and higher number of outliers. Longitudinal analysis of routine tests showed clearly that turnaround time values became shorter in every unit during the 1st 6 months of 2006. Clinical validation is an important component altering turnaround time that can be shortened substantially with the installation of an autovalidation program. Based on the data of the authors the median turnaround time values of routine assays were shortened by 1-2 hours after introduction of autovalidation. The applied program for turnaround time analysis is suitable for evaluation of sample transfer times, too, that was presented by comparison of two "emergency units" having different sample transfer facilities. CONCLUSIONS: The described turnaround time analysis is part of the general routine processes in laboratories of the developed countries but is the first such trial in Hungary.