Short-term stability of urine electrolytes: effect of time and storage conditions.

The purpose of this investigation was to quantify the effects of storage temperature and duration on the assessment of urine electrolytes. Twenty-one separate human urine specimens were analyzed as baseline and with the remaining specimen separated into eight vials, two in each of the following four temperatures: 22, 7, -20, and -80°C. Each specimen was analyzed for urine electrolytes (sodium, potassium, and chloride) after 24 and 48 hr. After 24 hr, no significant difference was detected from baseline in urine sodium, potassium, and chloride at all four storage temperatures (p >.05). Similarly, after 48 hr, urine sodium, potassium, and chloride were not significantly different from baseline in all four storage temperatures (p >.05). In conclusion, these data show that urine specimens analyzed for urine sodium, chloride, and potassium are stable up to 48hr in temperatures ranging from deep freezing to room temperature.