Are You Pregnant? Pregnancy Tests Can You Measure hCG Levels in Your Urine? How Home Pregnancy Tests Detect This Hormone By Robin Elise Weiss, PhD, MPH twitter linkedin Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor. Learn about our editorial process Robin Elise Weiss, PhD, MPH Reviewed by Reviewed by Rachel Gurevich, RN on July 25, 2020 facebook twitter linkedin Rachel Gurevich, RN, is a registered nurse, fertility advocate, author, and recipient of The Hope Award for Achievement, from Resolve: The National Infertility Association. Learn about our Review Board Rachel Gurevich, RN Updated on February 12, 2021 Print Photo © The Image Bank / Getty Measuring hCG in urine is how home pregnancy tests (HPTs) work. When you pee on a stick, the spongy material that soaks up your urine is treated to detect the presence of hCG, which stands for human chorionic gonadotropin—the hormone produced by the placenta, the organ that forms during pregnancy to provide nourishment to a developing fetus. Overview HCG usually is present in urine by 10 days after a newly pregnant woman misses her first period, which typically is when the fertilized egg attaches to the walls of the uterus. Urine tests can't confirm pregnancy as early as blood tests performed by a doctor can, of course. But since they first became available in 1977, HPTs have become more and more sensitive and now can confirm a pregnancy within a few minutes. They've also become much easier to use. The first home tests involved purified water, test tubes, and other items, plus a lot of patience. What an HPT can't tell you, however, is how much hCG is in your urine. This is relevant because during the first several weeks of a pregnancy that's progressing normally, hCG levels rise rapidly. When hCG levels don't increase as expected, it can be an indication that the pregnancy may not be viable. Often the hCG levels of a woman who got pregnant while undergoing infertility treatment will be monitored closely by her doctor to make sure everything is developing as it should. The Early Symptoms of Pregnancy How Reliable are HPTs? Most home pregnancy tests claim to be 99% accurate, but research shows that not all brands are equally sensitive. While some tests can give reliable results as soon as a woman misses her period, there's a chance of getting a false-negative that early. Since the sooner after learning she's expecting a woman should begin making lifestyle changes to support the healthy development of her baby, if she gets a false-negative on an HPT and assumes she's not pregnant, she may continue to do things that could affect her pregnancy, such as drinking or smoking. For this reason, the U.S. Food and Drug Administration advises waiting one to two weeks after you've missed your period to use an HPT. What about a false-positive result? This is very rare; if you aren't pregnant your body simply will not product hCG. However, if you became pregnant and then lost the pregnancy without knowing it, there might be enough residual hormone in your urine for an HPT to detect. Other potential causes of a false-positive home pregnancy test include gestational trophoblastic diseases, menopause, or problems with the ovaries. Getting Accurate Results Again, you should wait a week or two after you miss your period to do a home pregnancy test. If you've been trying to get pregnant and you want to do one sooner, of course that's fine; just don't be disappointed or assume you didn't conceive if you get a negative results. Wait and do the test again if you don't get your period after a week or two. It's best to do pregnancy tests first thing in the morning. This is when your urine is most concentrated and will contain the highest and most easily detectable amounts of hCG. Most importantly, read and follow the directions that came with your test. Some provide detailed instructions for how to hold the stick and for how long to leave it in your urine stream, for instance. And always follow up with your doctor as soon as you get a positive result on a home pregnancy test. Was this page helpful? Thanks for your feedback! Get diet and wellness tips to help your kids stay healthy and happy. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. U.S. Food & Drug Administration. Pregnancy. Gnoth C, Johnson S. Strips of hope: Accuracy of home pregnancy tests and new developments. Geburtshilfe Frauenheilkd. 2014;74(7):661-669. doi:10.1055/s-0034-1368589 Additional Reading Cole LA. Individual deviations in human chorionic gonadotropin concentrations during pregnancy. Am J Obstet Gynecol. 2011;204(4):349.e1-7. doi:10.1016/j.ajog.2010.11.036 Johnson SR, Godbert S, Perry P, et al. Accuracy of a home-based device for giving an early estimate of pregnancy duration compared with reference methods. Fertil Steril. 2013;100(6):1635-41.e1. doi:10.1016/j.fertnstert.2013.08.031 Korevaar TI, Steegers EA, De rijke YB, et al. Reference ranges and determinants of total hCG levels during pregnancy: The Generation R Study. Eur J Epidemiol. 2015;30(9):1057-66. doi:10.1007/s10654-015-0039-0 Larsen J, Buchanan P, Johnson S, Godbert S, Zinaman M. Human chorionic gonadotropin as a measure of pregnancy duration. Int J Gynaecol Obstet. 2013;123(3):189-95. doi:10.1016/j.ijgo.2013.05.028