Background: Samples with limited volume is a common problem in laboratories receiving samples from pediatric patients. Also, pediatric samples may contain nucleated red blood cells (NRBC) which distorts the white blood cell (WBC) count and which can only be measured by some automated cell counting systems. Differential counts are sometimes required, posing the question of validity of flagging depending on age of the patients and on predilutions.
Methods: We evaluated the hematology analyzers XE-2100 and XS-800 for their suitability in measuring hematological parameters in such samples.
Results: With the exception of the MCHC and partly the MCH, we observed very good agreement between complete blood counts (CBC) in diluted and undiluted samples. Dilution did not impair sensitivity in the clinically relevant range nor, accuracy of the NRBC count on XE-2100. Flagging was ineffective in undiluted samples from children<1 year of age and in all diluted samples when measuring differential counts.
Conclusions: In summary, while automated measurement of CBC and NRBC is possible in diluted samples, measurement of differential counts is restricted by loss of flagging efficiency. In addition, flagging is also ineffective in children<1 year of age using the analyzers evaluated and should, for diagnostic purposes, be performed manually.