Yes, pregnancy tests expire but you may still get an accurate reading

May 2024 ยท 4 minute read

Redeem now

There are two types of pregnancy tests: urine and blood. Both test for the hormone called human chorionic gonadotropin (hCG), which you start producing after implantation. But only one test expires. 

Pregnancy tests will expire in a couple of years

Blood pregnancy tests do not expire because analysis happens in a laboratory rather than at home. You can get one at a doctor's office, where they will draw a blood sample to be sent out for testing.

However, the more common urine pregnancy tests, which you can pick up at your local pharmacy, can and do expire. 

The way pregnancy tests work is that they are coated in a special type of lab-made antibody. Normally, antibodies are proteins that our immune systems produce to fend off infection and disease, like the flu. But we can also synthesize antibodies in the lab for many different types of tests that can diagnose everything from infectious diseases to pregnancy. 

The antibodies in home pregnancy tests react specifically to hCG, but will slowly evaporate and become less effective over time.

"Like many pharmaceuticals, pregnancy tests last for two to three years," says Dr. Paul Blumenthal, MD, an OB-GYN and Professor at Stanford University whose research includes pregnancy tests.

However, this does not mean that the test will last for two years after you buy it, Blumenthal says. It may have spent a considerable amount of time sitting on a store shelf. So, you should always refer to the expiration date on the package to be certain.

Certain conditions can also affect how quickly pregnancy tests expire. It is generally recommended to store pregnancy tests at room temperature, or at least between 36 and 86 degrees Fahrenheit. If you leave your test in a blistering hot or freezing cold car, for example, it might be safer to buy a new one.

What happens if you take an expired pregnancy test

Because urine tests become less sensitive over time, they will eventually lose their ability to detect pregnancy entirely. This means if you use an expired pregnancy test, you are more likely to get an inaccurate result. 

Most likely, you'll get a false negative, which is when your test says you're not pregnant but you are. While less common, you can also receive a false positive, when the test says you're pregnant but you're not.

It's possible that you can still get an accurate result from an expired pregnancy test โ€” especially if you're more than a few weeks into your pregnancy and your hCG levels are really high, Blumenthal says. 

But he adds that it's best not to chance it and just stick with pregnancy tests that are not past their expiration date. "Avoid using expired tests if at all possible," Blumenthal says.

If you are feeling the symptoms of early pregnancy โ€” like nausea, vomiting, or breast tenderness โ€” but your pregnancy test comes out negative, this may be a good time to double-check the expiration date on the box or go get tested at your doctor's office.

Related stories from Health Reference:

Madeline Kennedy is a health writer for Insider covering a wide range of topics including reproductive and sexual health, mental health, nutrition, and infectious disease. Before joining Insider, Madeline worked as a health news writer for Reuters, and a domestic violence therapist. She has a master's degree in social work from UPenn and is interested in the intersection of health and social justice. Read more Read less

ncG1vNJzZmivp6x7o8HSoqWeq6Oeu7S1w56pZ5ufonyowcidnKxnmJqurcDHaKmeqKKksbav06KtnmWYmq6twMdom6hloKeyqLrAp5qyZaSawLW%2FjJ6vqaGimg%3D%3D