Abstract: A colored intercapsular buffer solution is used to reduce erroneous results from the absorption or carryover of small amounts of reagent R1 and/or R2 into the intercapsular buffer solution segment in the analytical line of a capsule chemistry liquid analysis system in an automated clinical analyzer. The absorption of small amounts of the regent R1 and/or R2 in the intercapsular buffer solution leads to erroneous results in the analysis of the test sample, S, because the R1 and/or R2 that is carried over and absorbed into the buffer does not react with test sample S. The R1/R2 carryover can be measured and determined by monitoring the absorbance of the colored buffer solution, wherein the change in absorbance can be measured and compared to a reference value. The sample is automatically retested if an unacceptable change in absorbance occurs.

Abstract: The enumeration and analysis of residual white blood cells in a sample of leukocyte-reduced blood products is conducted by forming a suspension of the leukocyte-reduced blood products with a sufficient amount of a lysing reagent. The lysing reagent comprises a buffer with a low molar concentration, and a non-ionic surfactant. The suspension of leukocyte-reduced blood products and the lysing reagent is incubated for a sufficient time at a temperature sufficient to selectively lyse the platelets and red blood cells without damaging the white blood cells. The white blood cells of the lysed blood products are then contacted with a suitable dye to stain the white blood cells and the number of stained white blood cells is measured. The lysing reagent is free of harsh organic solvents which can damage the plastic components of automated clinical analyzers.