Advances in clinical chemistry
Publisher Summary A brief summary of nonglucose melliturias, exclusive of galactosuria, is presented. Mellituria is categorized into the following groups: (1) urinary sugars found in normal individuals, (2) mellituria secondary to hepatic or renal damage, (3) mellituria resulting from abnormalities in the gastrointestinal tract, and (4) heritable abnormalities resulting in a deficiency of an enzyme, primarily in the liver, that is necessary for the normal metabolism of sugar. The metabolism of different sugars is summarized and methods for identification are enumerated. The first step in the study of mellituria of any type is the detection of the presence of an increased amount of sugar in the urine. The finding of urine that has a positive Benedict reaction, but a negative glucose oxidase reaction, is the simplest screening method for the detection of nonglucose melliturias. Urine specimens that are collected for identification and quantitation of the sugar(s) present can be adequately preserved by adding toluene to the container and keeping the urine cool until processed. The chapter describes conventional techniques, quantitative colorimetric methods, and paper chromatography. Ionophoresis is employed for the separation of sugars and has the advantage of speed; the separation requires only 2 hours. The chapter discusses clinical conditions associated with mellituria.