False-positive results are rare. However, because home pregnancy tests are increasingly sensitive, some can detect very early pregnancies with low HCG levels. This sensitivity means it is possible to have a positive test that a very early miscarriage then follows. A woman who delayed testing or who used a less sensitive test might not have known about the miscarriage. In rare cases , a woman can have abnormally high levels of HCG even though they are not pregnant.
The most common reasons for this include:. In addition to testing too early, the following factors can cause a false negative with a urine HCG test:. Tests that have passed their expiry date may produce false positives or negatives. Reused tests are not accurate. HCG tests are very safe. The urine test is risk-free. The blood test can cause brief pain and occasional bruising at the puncture site. Urine HCG tests often return false-negative results, particularly very early in pregnancy.
This can be stressful and demoralizing to people struggling to become pregnant. Blood tests are typically more accurate, though even these may fail to pick up low levels of HCG in early pregnancy. It is also possible to get an early positive result. Some women get positive tests very early in pregnancy and then have a miscarriage a few days later. If they had not had an early HCG test, they might not have known they were pregnant.
This can be a stressful and alarming experience, with some people experiencing intense grief over the lost pregnancy. Most people first learn about a pregnancy through a home HCG pregnancy test, and many confirm that the pregnancy is healthy with blood HCG testing. Though imperfect, the test is typically reliable, particularly as a pregnancy progresses. The urine test can typically detect pregnancy 10 days after your first missed period. During the first eight to ten weeks of pregnancy, the levels of HCG rapidly increase in your body.
The urine test does not reveal specific amounts of the hormone in your system, rather that the hormone is present in your body. Results typically can be seen about as soon as two to three days after implantation and double every two to three days. List of Partners vendors.
Blood tests can confirm pregnancy by checking for the presence of the hormone, human chorionic gonadotropin hCG. These tests are more sensitive than urine tests and can detect a pregnancy earlier. Blood pregnancy tests are more sensitive than urine tests. They are typically reserved for those struggling with infertility or a suspected miscarriage.
A blood test can confirm pregnancy as early as nine days after conception. Urine pregnancy tests will take at least 10 days or longer.
Blood pregnancy tests have to be taken at the doctor's office. Your doctor might advise you to wait until a missed period to do any type of pregnancy testing so you can get the most accurate result. Testing too early can produce a false negative. Unlike home pregnancy tests, you'll have to wait for a blood pregnancy test result to come back from the lab. There are two types of blood pregnancy tests:.
HCG doubles every couple of days in the very early stages of pregnancy. Urine tests can produce a false negative if the urine is diluted from over-hydration or the test is taken too early. A false negative test is negative, but you're pregnant can occur if the blood pregnancy test was performed too early. There may not be enough hCG in the blood to detect a pregnancy.
Beyond testing too early, a false negative blood test can occur if there is a condition called gestational trophoblastic disease. In this case, the lab will need to dilute the sample before performing the test to get an accurate result. False positives test is positive, but you're not pregnant very rarely happen. Both have the same ability to detect hCG in your urine. Most hCG urine tests sold for home testing follow a similar procedure for accurate testing.
While you should carefully follow the instructions included with your kit, the process typically goes like this:. Wait 1 to 2 weeks after your first missed period.
Irregular periods or miscalculations of when a period is due can affect your test. Plan to use the test the first time you urinate after waking up. This urine is the most concentrated and will contain the highest hCG levels of the day. Your urine dilutes as you drink liquids, so hCG levels may be harder to measure later in the day.
Other kits require that you collect urine in a cup and then dip the indicator stick into the cup to measure the hCG hormone level. Home pregnancy tests usually include an indicator that shows whether the test is being properly performed.
For most tests, it only takes about 5 to 10 minutes for a result to appear. Typically, a colored line or plus symbol will appear on the test stick to indicate a positive result. The absence of a colored line or a negative sign usually indicates a negative result.
If you have a negative result, you should consider these results to be uncertain, as they may indicate a false negative. Smoking, using alcohol, and taking certain medications can harm your baby in early pregnancy.
0コメント