Regardless of the cause, the resulting inconclusive or incorrect test result is probably the last thing you want, especially if the potential pregnancy is unexpected. Thankfully, there are some simple things you can do to ensure the accuracy of your at-home pregnancy test results and avoid any test-related confusion or anxiety.
Resist the temptation. HCG or Human chorionic gonadotropin is a hormone produced by cells that are surrounding a growing embryo, which eventually forms the placenta after implantation. The elevated presence of hCG is used to signal pregnancy. However, hCG takes time to build up in the body. So, even if implantation of an embryo occurred on a Monday, if you take a pregnancy test on Wednesday, it may still give a negative result. If you think you might be pregnant and already missed your period, wait 3 days and take another test.
If there is hCG in your body, indicating a pregnancy, it will build up in your urine overnight and peak in the morning. Using a pregnancy test first thing in the morning will help you get an accurate result. Most tests instruct you to hold the test under your urine stream, but this is messy and risks error, like not getting enough urine on the test strip. This method also increases the likelihood of the test falling into the toilet by accident.
Makers of pregnancy tests advise that tests taken in the first week or two after conception could be inaccurate because pregnancy hormones may not have risen high enough to be detected. But Ann Gronowski, PhD , a professor of pathology and immunology, and of obstetrics and gynecology, and medical director of core laboratory services at Barnes-Jewish Hospital , discovered that pregnancy tests can also give incorrect results to women five weeks or more into their pregnancies, when hormone levels tend to be very high.
She published the first paper describing this problem in , and since then has continued studying and raising the alarm on this serious but under-recognized issue. Recently, she and colleagues published a paper in the journal Clinical Chemistry, in which they evaluated how likely several pregnancy devices were to give false negative results. Q: How did you discover that some pregnancy tests produce false negative results? About a decade ago, a woman came to the emergency department saying she was pregnant and was experiencing cramping and spotting — which can be signs of miscarriage — but the pregnancy test we gave her at the hospital came back negative.
She was certain she was pregnant, so we performed a blood test and an ultrasound, both of which confirmed she was pregnant. Shortly afterward, we had a similar experience with a second patient, and at about the same time a colleague at Vanderbilt University called me with a similar observation. So we started investigating, and we published a paper describing the problem and its cause.
We use a kind of pregnancy test in the emergency department that is similar to what you can buy at a drugstore. But if you do miscarry, a doctor can check for any leftover tissue with an ultrasound scan. You may need to have a procedure to remove the tissue. One way to do this is to dilute your urine before using a pregnancy test. After peeing in a cup, add a few tablespoons of water to your urine so it becomes lighter in color.
This might work because it reduces how much hCG you have in your urine. Another way is to avoid doing a urine pregnancy test first thing in the morning. Many at-home pregnancy tests advise you to take the test after waking up because your urine is more concentrated then. This means more hCG. Instead, try waiting until later in the day to take a pregnancy test. In the meantime, drink plenty of water as another dilution technique.
Getting a false-negative pregnancy test because of the hook effect is rare. False-negative test results can happen for many reasons. One older study that tested 27 different kinds of at-home pregnancy tests found that they gave false negatives almost 48 percent of the time.
You might get a false-negative pregnancy test for other reasons. Or you may take a test too early. It takes time for the hCG hormone to appear in your urine. Make a follow-up appointment a few weeks later and ask for another test and an ultrasound scan. If you have a molar pregnancy, you need urgent treatment and careful monitoring. You know your body best. Let the doc know that the tests might be wrong if you feel that you might be pregnant.
Learn about potential problems associated with rheumatoid arthritis and pregnancy, including triggers, preeclampsia, premature birth, and low birth…. Health family. Advertiser Disclosure. By Ashley Lauretta. Medically Reviewed Dr.
Commissions we earn from partner links on this page do not affect our opinions or evaluations. Our editorial content is based on thorough research and guidance from the Forbes Health Advisory Board. At-home Pregnancy Tests Find the most popular at-home pregnancy tests on Amazon. Compare Tests.
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