ABSTRACT
Urine is somewhat unstable, and if it is not tested soon after it is voided, it may be subject to deterioration or modification. The changes may be of an oxidative nature or involve a photolytic reaction, or be due to the growth and metabolism of microorganisms or the simple hydrolysis of a compound to less reactive derivatives. The deterioration of urine was observed by earliest man since there is a marked change in both the color and appearance of urine as it stands and a development of an odor which most persons find quite unpleasant. The clinical utility of preservatives lies in the fact that they can provide a valuable function when it is needed. Everyone agrees that urine specimens should be tested fresh for best results. In order to achieve good results with urine study when preservatives are employed, it is quite important to use the proper ratio of preservative to specimen.
