High concentrations of lithium heparin decrease measured serum sodium in some analyzers.

with 1 cell/HPF obtained with microscopy of the urinary sediment). Fewer epithelial cells and bacteria were seen in this population. In both groups, however, the values for erythrocytes and leukocytes varied, with ranges of ;1–36 cells/mL and ;3–57 cells/mL, respectively, when the results between the 5th and 95th percentile were examined. These values are obviously higher than those obtained with microscopic examination of the urinary sediment. Thus, the results should be interpreted with care because the units obtained with the UF-100 (cells/mL) are obviously different from those obtained after centrifugation and microscopy of the urinary sediment (cells/HPF). This may be a problem at the beginning when clinicians are not used to the units of the UF-100. Our experience with certain wards, however, shows that clinicians will adjust to changes relatively quickly. The small round cells (SRCs) most probably originated from the tubular epithelium of the kidney or the transitional epithelium of the urinary tract. Very small quantities of these cells were seen in urine samples from both groups. Thus, the presence of up to 5 SRC/mL in neonates and up to 2 SRC/mL in children are within the 95th percentile and are not regarded as pathological. We hope that these values are helpful to those colleagues already using the UF-100 in routine urinalysis.