If you take a pregnancy test at home, there are several things to be aware of so that you don't get a false positive result--or a false negative. Using the pregnancy test according to the manufacturer's instructions is one way to ensure the accuracy of your results, the Mayo Clinic says. But in certain circumstances, the most error-proof pregnancy test results may need to come from a health care provider.
Pregnancy Testing Overview
All types of pregnancy testing, be it through the collection of urine or a blood sample, detect whether a hormone called human chorionic gonadotropin (HCG) is present in your body, says the National Institutes of Health. HCG shows up in your body around 10 days after you conceive. Pregnancy testing using a blood sample can confirm pregnancy either qualitatively, by determining if HCG is present; or quantitatively, to ascertain the amount of HCG is present.
Home Pregnancy Tests
The Mayo Clinic indicates that most home pregnancy tests work in a similar way-- either by holding the absorbent tip of a testing stick under the flow of urine, dipping the tip into a clean container of urine or applying urine to the test stick with a dropper. After a certain amount of time--usually only a few minutes--the display window on the test stick may reflect a plus sign, colored line or the word "Pregnant" to indicate a positive result. Most home pregnancy tests claim that you can use them as soon as the first day of your period. But Mayo Clinic experts indicate this might not be a good idea.
Better Results
Mayo Clinic experts indicate that only very low levels of HCG may be present in your body if you're pregnant, even on the first day of a missed period. This may give you indeterminate results on your home pregnancy test. To get the most accurate results from a home test, the Mayo Clinic advises waiting a week after you miss your period. If you need to know if you're pregnant sooner rather than later, blood testing performed at a doctor's office or laboratory can detect if you're pregnant as early as six to eight days after your ovulation date, says the National Women's Health Information Center.
False Results
False positive results aren't common, says the Mayo Clinic, but they can occur if you have blood or protein in your urine, if you're taking medications such as diuretics or promethazine, or if the date on the home pregnancy testing kit has expired. It's more likely that you'll get a false negative result; Mayo Clinic experts indicate this may occur if you test for pregnancy too early, test more than 15 minutes after taking your urine sample or drink too much fluid before you take the test, which dilutes your urine. The Mayo Clinic advises that if you want to increase the accuracy of your pregnancy test kit, test the first thing in the morning when your urine is highly concentrated.
Now What?
If your home pregnancy test yields a positive result, the NWHIC advises contacting your doctor or another health care practitioner so you can get a pelvic examination to confirm pregnancy. Also contact your doctor if you take another pregnancy test two weeks after a missed period and still get negative results. A skipped period can be caused by a number of factors, including stress, illness and hormonal imbalance.
