Urinary Granulocyte Excretion in Renal Disease:  Comments on the Pyrogen Test

In his early studies of the urine sediment and of its significance in renal disease, Addis ^1,2 pointed out the need for measuring rate of excretion rather than concentration of formed elements because of the influence of volume, pH, and solute concentration on the latter. Since then sporadic efforts, primarily in England,^3,4 to relate white blood cell excretory rate to urinary tract infection, both as a diagnostic technique and as a means of assessing extent and chronicity of the process, have suggested that such enumeration is indeed more accurate and therefore of greater potential clinical value than the time-honored reporting by high-power field. In a further effort to extend quantitative sediment examination, the pyrogen test was introduced and has been considered helpful in evaluating pyelonephritis. ^5,6 This test permits comparison of hourly urinary leukocyte excretion rate before and after the intravenous injection of a standard dose of bacterial endotoxic