At-home pregnancy tests can be a very accessible and accurate way to find out whether you're pregnant. In fact, when used correctly, these urine-based tests are accurate up to 99% of the time. But if you're digging through your cabinet to find one you've had lying around, you may be wondering whether pregnancy tests expire and whether an old test can still give you accurate results.
The short answer is yes, pregnancy tests do expire, but getting accurate results is a bit more complicated than just using a test before its expiration date. To get all the details, we talked to two gynecologists who offered their insights on home pregnancy tests, from how they work to when they expire and how to get reliable results.
Pregnancy Test Expiration Dates and Shelf Life
Yes, pregnancy tests expire. Like other medical products in your medicine cabinet, pregnancy tests carry an expiration date based on how long the manufacturer has determined the test reliably provides accurate results. It's after this expiration date that the manufacturer cannot guarantee the accuracy of the test's results—even when used according to the instructions. Every pregnancy test has a shelf life, no matter what company manufactures it or what kind of test it is.
The shelf life of a home pregnancy test will depend on the brand, but according to Stephanie Hack, MD, an OB-GYN andfounder of Lady Parts Doctor, pregnancy tests are typically good for two to three years after the date they were manufactured. This guideline applies to both digital tests (which contain extras like an optical sensor and battery) and basic non-digital tests.
How Home Pregnancy Tests Work
Home pregnancy tests work by detecting the presence of the hormone human chorionic gonadotropin (hCG) in urine, says Carolyn Ross, MD, an OB-GYN and medical advisor at Winx Health. "This hormone is produced by cells that form the placenta after a fertilized egg implants in the uterus," she explains.
When Are Urine Pregnancy Tests Most Accurate?
While there are home pregnancy tests that are sensitive enough to provide early results, all urine-based pregnancy tests are most accurate when taken after your missed period. Home pregnancy tests can detect hCG in urine 12–15 days after ovulation. Blood-based pregnancy tests like those you might get at a health care provider's office, on the other hand, can detect hCG much sooner.
The tests contain an antibody that reacts with hCG. This chemical reaction causes the antibody to create either a colored line, a plus sign, or a digital positive. If you're not pregnant, your urine won't have detectable levels of hCG and won't cause the reaction. But if you are pregnant, the hCG your body produces will eventually get to detectable levels in your urine, triggering a positive test result.
An expired test can lose the ability to produce this chemical reaction.
Tip
Most home pregnancy tests instruct you to pee directly onto the pregnancy test or dip it in a small cup of urine. Either way, you'll want to be sure that the control line (or its digital counterpart) appears to confirm that the test is working as intended.
Are Expired Pregnancy Tests Still Reliable?
If a pregnancy test has passed its expiration date, it may not be able to detect hCG in your urine. This is because the antibodies used to detect the hormone may degrade over time, which can cause a false negative result. This is when you're actually pregnant, but the test indicates that you're not. If you're questioning a result, you should always check with a health care provider.
The bottom line is that an expired pregnancy test might still be able to give you an accurate result, but there is much more room for error.
Tip
While it's safe to remove pregnancy tests from the box they came in and store them separately, you should never unwrap an individual test until you're ready to use it. Keeping individual pregnancy tests in their wrappers is one way of ensuring proper storage and makes sure you can recheck the expiration date before using it.
How To Know If Your Test Has Expired
Every home pregnancy test will have an expiration date printed somewhere on the product. If you want to find out if your test has expired, check for a date stamped on the box, either on the side or bottom. You may also want to check the foil wrapper of the test stick or the stick itself, as manufacturers also stamp each test individually.
Pregnancy tests are sensitive to extreme temperature fluctuations, so store them where the temperature never falls below 36 degrees or rises above 86 degrees Fahrenheit. Improper storage risks degrading the components of the test and compromising its ability to deliver accurate results. Tests can be compromised by improper storage at any time—including before the expiration date.
What To Do With Expired Tests
If you have expired pregnancy tests in your cabinet, the best thing to do is dispose of them. This will ensure you don't grab one and risk an inaccurate result. To be safe, invest in a new unexpired test or speak to your health care provider about getting a beta hCG blood test, which can be done at your provider's office or a lab.
How To Take the Most Accurate Pregnancy Test
In addition to checking the expiration date, use these tips to ensure your results are as accurate as possible:
- Take the test first thing in the morning: Your urine is the most concentrated when you first wake up, potentially increasing the amount of hCG in your urine.
- Don't check for results too soon: Read the instructions carefully and wait the recommended time before reading the results. Many tests require at least five minutes. Set a timer and resist checking until the time is up.
- Wait until after your first missed period: Even if you suspect you may be pregnant, wait until the first day of your missed period to test. Otherwise, it may be too early for the test to detect hCG.
