No preservatives.
Preprandial (before meals) or fasting samples are preferred to avoid dietary artifacts and enhance sensitivity.
Urine should be stored at -20°C and shipped frozen on dry ice. Sample may be kept at room temperature for up to 4 hours. After this time, keep sample cold at 4°C for up to 24 hours. Freeze if stored for longer than 24 hours before shipping. If transportation to lab is same day as collection, (local hospitals only) the sample must be transported at 4°C on an ice pack or frozen on dry ice.