UriSed - Preliminary reference intervals and optimal method for urine sediment analysis in newborns and infants

The aim of this study was to establish reference intervals for urine sediment in newborns and infants in the second month of life for the UriSed automated analyser and for bright field microscopy. We also aimed to provide an optimal protocol for UriSed analysis, which best corresponds to the results of manual microscopy.

Urine sediment analyses of 75 healthy newborns and infants in the second month of life were performed by manual microscopy and UriSed automated analyser (two modes: 15 and 20 images per sample). Images were then reviewed and manually corrected by an operator when needed.

We observed statistically significant differences between bright-field microscopy and UriSed (when manual correction was not performed) for squamous epithelial cells and red blood cells counts (P<0.0001). There were no differences based on the number of images per sample (P>0.05). Upper reference values for bright-field microscopy and UriSed analyser taking 15 images per sample with manual correction (method we recommend) were as follows: squamous epithelial cells: microscope 8.7×10(6)/l, UriSed 6.4×10(6)/l, non-squamous epithelial cells: microscope 4.3×10(6)/l, UriSed 3.9×10(6)/l; erythrocytes: microscope 5.9×10(6)/l, UriSed: 4.6×10(6)/l; leukocytes: microscope 8.6×10(6)/l, UriSed 9.9×10(6)/l; hyaline casts: microscope 0×10(6)/l, UriSed (no correction) 0.7×10(6)/l.

We established preliminary reference intervals for urine sediment analysis in newborns and infants for UriSed and bright-field microscopy. We concluded that for routine laboratory examination of non-pathological urine it is enough to use the faster mode, with 15 images per sample, followed by a manual correction.