What happens when urine is allowed to stand?
When urine is allowed to stand, several changes occur due to the presence of various chemical compounds and biological processes:
Ammonium Formation: At room temperature, bacteria present in urine break down urea, a nitrogenous waste product, into ammonia. This conversion leads to an increase in the pH of urine, resulting in a stronger alkaline environment.
Cloudiness: As urine becomes alkaline, it can form cloudy precipitates composed of calcium phosphate, calcium carbonate, and other minerals. These precipitates make the urine appear hazy and less transparent.
Smell Changes: The breakdown of urea by bacteria produces ammonia, which carries a strong, pungent odor. As the urine's pH rises and the bacterial decomposition of organic compounds continues, other malodorous compounds may also develop, contributing to the unpleasant smell.
Color Changes: Freshly passed urine is typically yellow to amber-colored due to the presence of a pigment called urobilin. As urine ages, it may undergo further oxidation, resulting in color changes from yellow to amber, orange, or even a darker reddish hue. These changes are caused by the breakdown of bilirubin, another pigment found in urine.
Bacterial Growth: The longer urine stands, the more time it has for bacteria to grow and multiply. This can lead to a higher bacterial concentration, which may result in a foul odor, cloudiness, and an increased risk of urinary tract infections (UTIs).
Sedimentation: Over time, the heavier particles and precipitates present in urine settle at the bottom of the container. This sedimentation forms a layer of sediment that consists of various cellular components, such as white blood cells, red blood cells, epithelial cells, and crystals.
It's important to note that the rate of these changes depends on factors such as temperature, the initial concentration of various compounds in urine, and the presence of specific bacteria strains. It is generally advisable to analyze fresh urine samples whenever possible to obtain accurate and timely medical information.