The Most Accurate Pregnancy Test
When women think they might be pregnant, their first stop is usually the drugstore, to pick up the most accurate pregnancy test they can find. Numerous boxes claim to be 99% accurate, but are they really?
Studies have found that home pregnancy tests can be up to 97% accurate when used exactly as directed - but most users, assuming they know how the pregnancy test works, reduce that accuracy to 75% by not reading or misunderstanding the directions. For the most accurate pregnancy test, you'll have to visit your doctor.
The Importance of Sensitivity
All pregnancy tests are looking for the same hormone. Home pregnancy tests measure its presence in your urine, and the doctor's tests measure for it in your blood. This hormone, human Chorionic Gonadotropin or hCG for short, is produced by the trophoblast cells of a fertilised egg. However, getting an accurate pregnancy test result depends on the type of test used and the timing. A test taken too soon can result in a false negative.
Your doctor may do either a qualitative blood test or a quantitative blood test. A quantitative blood test is highly sensitive, able to detect as little as 1 mlU/mL, or roughly the amount produced shortly after implantation. For comparison, consider that the "most accurate pregnancy test" variations marketed in your local store measure between 20 mlU/mL and 100 mlU/mL. This means that a quantitative blood test, taken six to twelve days after ovulation, can return accurate results. Based on that, this would be the most accurate pregnancy test.
However, some women are willing to temporarily sacrifice accuracy for convenience and peace of mind. Though it may not be an accurate pregnancy test, they're just looking for a result - something to reassure them when they're suspicious they might be pregnant. These are usually the low-cost pregnancy tests available at your local drugstore.
False Results
As previously stated, tests taken too soon can result in a false negative. If your level of hCG is too low to be detected, or nonexistent because implantation hasn't yet taken place, you might be led to believe you aren't pregnant by a less-than-accurate pregnancy test result. You should always wait until your period is late to test for pregnancy; this gives a fertilised ovum plenty of time to settle into the uterus and begin releasing hCG.
On the other hand, false positives may occur if a home pregnancy test is not handled carefully. 'Evaporation lines' appear in the reading windows of these tests if they're read after the standard three to five-minute time frame, which might give the appearance of a positive result. Expired pregnancy tests are unreliable and cannot be expected to result in an accurate pregnancy test. Some diseases and medications produce hCG in levels which a home pregnancy test could interpret as a positive result.
If you've tested at home for pregnancy but you have your doubts as to whether it was an accurate pregnancy test, consult your doctor. With a quantitative blood test and a brief series of questions, your doctor can easily determine whether or not you're actually pregnant, and put all your questions to rest.
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