If you’re trying to find out you’re pregnant, you’ll be getting a lot of practice of ‘peeing on a stick’ (or in a cup) to use your urine for a pregnancy test. However, many of us can’t just pee on demand – and pregnancy tests often say to use morning urine, as well. What if that’s just not convenient?
Whether it’s the wrong timing or you want to take a test at a more practical time, here’s a guide to how long your urine can last before using it for a test later – and how to store it so you don’t get false negatives.
Collecting urine for a pregnancy test
You do need SOME preparation here, especially with the container you choose.
It’s best to use a clean, sealable container with a lid (such as an empty water bottle or jar). Alternatively, you can use a food-grade sealable plastic bag (but make sure it does seal, for obvious reasons). By ‘clean’, this should be sterile so the sample doesn’t get contaminated, and to reduce the risk of bacteria.
Dishwashers do a great job of sterilizing jars on a hot wash, or you can wash the container in hot, soapy water – but give it a good rinse, and let it dry.
Many of the techniques for sterilizing containers for food will work well here.
As many pregnancy tests will tell you, it’s best to collect your first morning urine because is most concentrated. You want to make sure that it’s the first urine you pass in the morning, so try and go right when you wake up and go to the bathroom.
If you need to empty a full bladder, try to catch the ‘mid flow’, though this might be difficult! Remember to wash your hands, before and after. Then seal the jar or container.
What to do with the collected sample
Urine ideally needs to refrigerate within an hour of collection or it will spoil. It is best if you can store the sealed container upright, in case it leaks when laid on its side.
You must store the urine somewhere cool like in the refrigerator or a cooler with ice packs. Urine will spoil if it’s not kept cold – more on this below. You may decide to label the bottle or jar “DO NOT DRINK, for obvious reasons!
Also, because urine is quite warm when it leaves the body, give it ten minutes or so to cool down before putting it in the fridge, otherwise, it might increase the temperature of your fridge to unsafe levels.
The importance of storing urine at refrigeration or below
Urine spoils if stored at a temperature higher than around 39.2f/4c, which is the temperature most fridges operate at (check that yours is cold enough). Bacteria growth (and resulting spoilage) is much more likely to occur above this level.
This problem applies not only to pregnancy tests but to urine in general – if you want to save your own urine for use in home pregnancy testing kits, or if you have access to stored urine and want to check its validity, you need to keep it at 39.2f/4c or lower.
How long you can store your sample in the fridge before it spoils
Urine can be saved for up to 24 hours after it is first voided (the medical term for having a pee).
Pregnancy test kits can still be used within these 24 hours. How is this possible? Well, urine is a sterile (clean) substance when it leaves your body, and refrigeration will keep it that way, preventing bacteria from growing in the urine and spoiling the results of the test.
After this time, it will start to spoil, so do not keep urine longer than 24 hours (nhs.uk).
If more than 24 hours pass, then the urine should be discarded (see how to do this safely below), and you’ll need a fresh sample.
When is it best to take a pregnancy test after collecting and saving your urine?
Ideally, you should use a pregnancy test as soon as you can after collecting and storing your urine. While it is theoretically possible for tests to detect the presence of hCG at low levels in urine after 24 hours, spoilage might mean that your test result may not be as accurate.
When you take your sample out of the fridge, use it as soon as you can – don’t let it sit at room temperature for too long.
How to dispose of urine properly
This sounds obvious, but after you’ve taken your sample, pour the urine away somewhere safe like the toilet, or outside. Don’t throw it out with regular household trash, as this could lead to serious problems for sanitation workers who come into contact with it.
Give the jar or water bottle a good wash, after you’ve poured out the urine, and then place it in your recycling bin. Alternatively, a cycle in the dishwasher is usually enough to kill bacteria if you want to re-use the container (if you can forget about the whole “pee” thing).
In conclusion, it’s always better to take a pregnancy test as close to the time you collect your urine as possible. This will give you the best chance of success.
If for some reason you can’t do this, saving and refrigerating your sample for up to 24 hours in a sterile container is a way to extend its life somewhat – but taking it out of the fridge too long before using it could compromise its effectiveness, too.