In earlier pregnancy tests, it could only check for the presence of hCG in the morning, when hCG was more concentrated in the urine. And it was in those earlier pregnancy tests that you often had to mix vials and test tubes to determine if you were pregnant. Fortunately, times have changed.
When you are testing at home, it is always best to use urine from the morning when you get up, especially if your period isn’t due yet, or is only late by a day or two.
If you tend to drink a lot of water throughout the day (which you should be when you are pregnant), it is also best to test in the morning, because water can dilute the hormone in your urine.
If you simply cannot wait until morning, try purchasing a two-in-one kit where you get two kits in the package, or by buying two kits. That way, you can test when you get home, and then saving one for the morning, if you do not get a definitive result.