In most cases it is best to collect your sample in the morning. As our service is mostly postal, this means that you will have plenty of time to make that day's post.
For any test which requires a fasting sample it is usually more convenient to take your sample after fasting overnight.
Some of our tests require you to take your sample at a specific time (or even several times during the day). If this applies to a test you are taking we will give you clear instructions about when to collect your sample.