Diameter measurements of urinary casts.

Abstract

Diameters of urinary casts in a number of pathological sediments have been measured and their frequency distributions studied. In most of the sediments measured the diameters range from about 8 microns to 40 or 50 microns, with a mean value of from 19 to 24 microns. Frequency polygons obtained from measurements of 100 to 300 casts grouped in class intervals of 3 microns are usually unimodal and slightly skew, with the long tail in the direction of the greater diameters. This asymmetry is probably due to the fact that very small casts are difficult of identification. A few of the sediments contained high percentages of broad “renal failure” casts described by Addis 1 . Plots from these sediments show high mean diameters and high degrees of dispersion, but are not otherwise significantly different from the other curves. In general the dispersion increases with increasing mean diameter. The broadest casts seen measured 98 microns.