Guessing how long it has been since performing the test can lead to false results. You should use a clock or a watch and record the time you perform the test and read results at the instructed time. Some tests will produce a faint positive test result if read after the instructed time. Your home pregnancy test instructions will specify when test results should be interpreted and when test results are no longer valid. Improper testing: When taking a home pregnancy test, it is very important to read the directions before testing. This is what happened to Kim Kardashian.Įvaporation line: If you read the test after the suggested time has passed. A rising blood hCG level usually indicates a pregnancy. False-positive urine tests can also occur under the following circumstances:įertility treatment: If you receive shots of hCG or gonadotropins (for example, Pregnyl, Profasi, Pergonal, APL) for ovulation, it's possible to have a positive urine or blood pregnancy test for two to three weeks after the shot and not be pregnant. However, a false positive pregnancy test can also happen after an hCG injection.īesides errors doing and reading the urine pregnancy test incorrectly, there are only a very few circumstances in which you can have a positive pregnancy test (false positive) and you are not pregnant. Any positive test appearing well after that time is inaccurate and cannot be considered positive. Once you have a negative test after 3-5 minutes throw out the test. Most manufacturers suggest you read their test after 3 minutes and to NOT READ it after 10 minutes. Pregnancy tests have certain instructions and they also differ from one another. One frequent cause of a false positive pregnancy test is simply reading the home pregnancy test incorrectly. Most women who have a positive pregnancy test are actually pregnant and only a few are not. A true negative pregnancy test means that your pregnancy test is negative and you are NOT pregnant.įalse-positive pregnancy tests are rare.A true positive pregnancy test means that your pregnancy test is positive and you are pregnant.A false negative pregnancy test means that your pregnancy test is negative but you ARE pregnant.A false positive pregnancy test means that your pregnancy test is positive but you are NOT pregnant.

Both false negative and false positive tests are possible. Another reason why you could end up with an evaporation line is if you accidentally splashed a bit of wee onto the results window when you were first using the stick.Įither way, if you checked your test within the time that the instructions said to and it was negative, then you are probably not currently pregnant.A pregnancy test checks for the presence of the pregnancy hormone human chorionic gonadotropin (hCG) in your body, usually in the urine or blood.They can quite easily be mistaken for a faint positive line, which could lead you to think that your result has changed from negative to positive. Unlike a positive result which will have a small amount of the red or blue dye the test uses to show them, evaporation lines are faint and colourless. That’s because after a while the urine on the test will evaporate, leaving what’s called an evaporation line. Most pregnancy tests will tell you to take your reading between 2 and 10 minutes after you pee on the stick, and if you read it after that the results are invalid. It’s most likely because you’re reading the test after the recommended time.There could be several reasons why your pregnancy test results go from negative to positive. Photo credit : Netmums user Dede80 Why did my pregnancy test change from negative to positive? Pregnancy tests measure the levels of pregnancy hormone hCG (human chorionic gonadotropin) in your urine and if the hCG hasn’t built up enough to register on a test, the your test will be negative. A false negative occurs when it’s just too early to tell if you’re pregnant. That said, you can get what’s called a ‘false negative’ on pregnancy tests. What a false negative on a pregnancy test? What it comes down to is: if your test said that you were not pregnant during the time window for taking a reading, then it is still negative EVEN IF you see a line after that time. If you look too late, you can end up with evaporation lines, which can trick you into thinking you have a positive result. That’s why the instructions on pregnancy tests tell you to look at the results within a certain time frame. Positive pregnancy test turned negative: What does it mean?.Read on to find out more about why this might happen. So what does it mean if your negative result somehow has turned into a positive one later on? Unfortunately, one way or another, it’s a sign that something has gone wrong with the test.

Negative positive pregnancy test