Clinical and Laboratory Observations on So-Called 'Kidney Threshold for Glucose'

"Renal threshold" is usually denned as that concentration of sugar in the blood above which sugar appears in the urine. If this definition could be literally applied in the diagnosis, prognosis, and treatment of diabetics, the whole matter of control would be a simple procedure. Urine analysis alone would be sufficient to judge the status of blood sugar. For many years physicians specializing in metabolic diseases have depended too much on urinary findings alone; at times, are confronted with cases where they are baffled by the inadequacy of the management and hence are led to question the laboratory results when there is a great discrepancy between blood and urinary sugars. With this paper we will attempt to present extensive observations on diabetic, and non-diabetic patients and also some experimental work on animals. Opinion differs concerning the importance of glycemia. Do urines negative for sugar necessarily indicate low or normal blood sugar levels? Do urines positive for sugar indicate hyperglycemia in normal or diabetic individuals? Does the testing of urines for sugar in diabetics offer a satisfactory means of control of the patients? Do diabetics build up a tolerance for glucose with the passage of years? Does infection always upset the glycemia levels, and give rise to glycosuria because of lack of control? In answering these questions the results assembled by clinical and