What happens when urine is allowed to stand?

When urine is allowed to stand, it undergoes chemical changes due to the growth of bacteria and the breakdown of urea into ammonia, which can result in an increased pH and a strong odor. Additionally, the presence of bacteria may lead to the formation of sediments and turbidity as cellular components break down. Over time, the urine may also become discolored and lose its clarity. These changes can affect its composition and potential use for diagnostic purposes.