Quantitative Estimation of Urinary Sediment, with Special Regard to Sources of Error

In 1959 Pears and Houghton observed that the pyrogenic agent "pyrexal" increased the urinary excretion of leucocytes in patients with chronic pyelonephritis. This observation has been used as a diagnostic test in pyelonephritis. Montgomerie and North (1963), however, found a wide spontaneous variation in the white-cell excretion in patients with chronic pyelonephritis and never encountered the steady rates of excretion noted by Pears and Houghton (1959). They thought that the test was not reliable enough to be of value in the diagnosis of chronic pyelonephritis. The test is based on exact counting of the cells in the urine, and knowledge of the errors involved in this procedure is therefore of great importance. The present study was carried out in order to correct some of the errors connected with quantitative estimation of urinary sediment.