Transportation time of inpatient specimens to the laboratory and its effects on test results

Abstract

Blood specimens should be transported to the laboratory as soon as possible and analyzed after adequate preanalytical treatments such as centrifugation. However, specimen transportation to the laboratory often takes a long time, especially for inpatient specimens. Since we considered that we should evaluate the turn-around time (TAT) in the laboratory as the time from sample collection to the reporting of test results rather than as the time from sample arrival to the reporting of test results, we investigated the time from inpatient specimen collection to specimen arrival at the laboratory. The mean transportation time was 91 ± 51 min, which was far longer than we had expected. We next examined the effect of transportation time on the test results at 4°C and room temperature. The blood glucose level decreased by 5.6% to 15.4% in 2 h and gradually decreased thereafter until 6 h. The plasma hANP level decreased by 8.4% to 24.4% at 4°C and by 18.9% to 41.3% at room temperature over 6 h. The serum potassium level increased by 26.8% to 28.2% at 4°C over 6 h. The serum lactate dehydrogenase level tended to increase at 4°C and room temperature, but the amount of increase varied widely depending on the specimen. The inorganic phosphate level decreased by 9.1% to 16.7% at room temperature over 6 h. The results of this study revealed the actual transportation time and the actual effects on test results.