Inaccuracy and inefficiency of urinary sediment analysis.

When the efficiency of urine sediment analysis was studied: we found that: (1) In tests of repeatability, counts of red blood cells, white blood cells, and epithelial cells, but not of casts, showed high precision, even when they were conducted by relatively inexperienced technologists; (2) Correlation of counts of red blood cells, white blood cells, and epithelial cells was good for results obtained by an expert technologist and those obtained by relatively inexperienced technologists, but the correlation was low in the case of casts, perhaps because of their low incidence in urine sediment; (3) Hematuria and leukocyturia were often detected in specimens positive for occult blood, albumin, or both; (4) Most casts were hyaline, which are physiologic in nature. Pathologic casts such as granular casts, were found in specimens containing red and white blood cells; (5) Although urine sediment analysis was frequently requested by clinicians, most analyses showed negative results; (6) Microscopic sediment analysis requires considerable time, labor, and experience, and is more sensitive than tape tests. The results of our study indicate that there are advantages to the present method for analyzing urine sediment, but that its efficiency is doubtful.