As with urine/home pregnancy tests, it is possible to end up with false results (both negative and positive) from a blood pregnancy test. A false negative (test is negative, but you’re pregnant) can occur if the blood pregnancy test was performed too early.
Can you have negative blood test and be pregnant?
Women may get a negative test result on a urine or blood pregnancy test despite being pregnant. Although many factors can contribute to a false-negative pregnancy test, the hook effect occurs when the woman has a high concentration of human chorionic gonadotropin (hCG), the pregnancy hormone.
What can cause a false negative pregnancy blood test?
But hCG is also responsible for the hook effect giving you a false-negative pregnancy test. The hook effect happens when you have too much hCG in your blood or urine. How is this possible? Well, the high levels of hCG overwhelm the pregnancy test and it doesn’t bond with them correctly or at all.
What does a negative blood pregnancy test mean?
If an hCG test comes back negative, that generally means you’re not pregnant. However, if the test was performed too early in the pregnancy, before your body has had time to produce enough hCG, you can get a false negative.
Can you be pregnant and have no hCG?
An early pregnancy test might pick up very low amounts of hCG. However, it’s possible that you don’t have enough circulating hCG to get a positive result even on a sensitive test. Another common reason for getting a false negative is not having enough hCG in the urine you test.
Can blood tests be wrong?
While they do have to meet very high standards, they can be wrong sometimes. For example, you might get a false positive (the results say you have the condition you were tested for, but you really don’t) or a false negative (the results say you don’t have a condition, but you really do).
How does blood test confirm pregnancy?
Blood tests can tell if you are pregnant about six to eight days after you ovulate. Doctors use two types of blood tests to check for pregnancy: Quantitative blood test (or the beta hCG test) measures the exact amount of hCG in your blood. So it can find even tiny amounts of hCG.
How accurate are blood tests?
When you get a medical test, you may be anxious about the results. For the most part, medical tests are helpful. But most tests are not 100 percent reliable, and the result of any single diagnostic test is not usually enough to make a diagnosis without looking at the big picture.
Can a blood pregnancy test be wrong at 2 weeks?
Qualitative hCG tests can detect elevated levels of the pregnancy hormone. But the hCG levels in blood and urine do not shoot up immediately when a woman becomes pregnant. Therefore, a test performed too early might produce an inaccurate result.
What is too early for a blood pregnancy test?
Blood tests are more sensitive than urine tests and can detect pregnancy as early as 6-8 days after ovulation. Unfortunately, most doctors will not perform the blood test until after the date that your period is due has past. The results of blood tests also take longer than a urine test.
What can affect HCG levels?
Causes of low hCG levels
- Gestational age miscalculated. Typically, the gestational age of your baby is calculated by the date of your last menstruation. …
- Miscarriage. A miscarriage is a pregnancy loss that occurs before 20 weeks of gestation. …
- Blighted ovum. …
- Ectopic pregnancy.
What is the longest it can take for hCG to show up?
A pregnancy test can usually detect hCG levels within 10 days of a missed period. Some tests can detect hCG even earlier, within a week of conception, but no test is 100% accurate.