1. Introduction

You have been asked by your doctor to collect a 24-hour urine sample. You will be provided with a bottle in which you are to collect all urine passed during a 24-hour period. The bottle contains a preservative, so please do not empty or wash it out. Keep the bottle in an upright position and avoid getting the preservative on your skin or clothes. Ensure that your full name, and the date and time of starting and finishing the collection are clearly written on the label on the side of the bottle. The collection may start at any time of the day but it usually most convenient if it is started in the morning.