We have placed a 24-hour restriction because Vivoo is a monitoring tool. If someone takes several tests in one day, our system can’t understand the improvements, and as such, it won't be able to provide the correct advice. Your urine results may change every day, even on an hourly basis for some parameters. If you want to get a better outlook of your body's data, Vivoo recommends that you always take your test around the same time of day each time you use it.