Characteristics of normal urine

• Volume

  One to two litres in 24 hours; varies considerably
• Colour

  Yellow or amber; varies with urine concentration and diet. Colour due to urochrome (pigment produced from breakdown of bile) and urobilin (from breakdown of haemoglobin). Concentrated urine is darker in colour. Colour affected by diet (reddish from beets), medications, and certain diseases. Kidney stones may produce blood in urine.
• Turbidity

  Transparent when freshly voided; becomes turbid (cloudy) on standing.
• Odour

  Mildly aromatic; becomes ammonia-like on standing. Some people inherit ability to form methylmercaptan from digested asparagus, which gives characteristic odour. Urine of diabetics has fruity odour due to presence of ketone bodies.
• pH

  Ranges between 4.6 and 8.0; average 6.0; varies considerably with diet. High-protein diets increase acidity; vegetarian diets increase alkalinity
• Specific gravity (density)

  Specific gravity (density) is ratio of weight of volume of substance to weight of equal volume of distilled water. In urine, 1.001–1.035. The higher the concentration of solutes, the higher the specific gravity.