How and When Pregnancy Tests Work

How and When Pregnancy Tests Work Pregnancy tests rely on the presence of the hormone human chorionic gonadotropin (hCG), a glycoprotein that is secreted by the placenta shortly after fertilization. The placenta begins developing after the fertilized egg implants in a womans uterus, which happens about six days after conception, so the earliest these tests can be used to detect pregnancy is about six days post-conception. Wait to Take Test Fertilization does not necessarily take place the same day as intercourse, so most women are advised to wait until they miss their period before trying a pregnancy test. Levels of hCG double about every two days in a pregnant woman, so the test increases in reliability over time The tests work by binding the hCG hormone, from either blood or urine to an antibody and an indicator. The antibody will bind only to hCG; other hormones will not give a positive test result. The usual indicator is a pigment molecule, present in a line across a home pregnancy urine test. Highly sensitive tests could use a fluorescent or radioactive molecule attached to the antibody, but these methods are unnecessary for an over-the-counter diagnostic test. The tests available  over-the-counter versus those obtained those at the doctors office are the same. The primary difference is the decreased chance of user error by a trained technician. Blood tests are equally sensitive at any time. Urine tests tend to be most sensitive using urine from early morning, which tends to be more concentrated (meaning it would have the highest levels of hCG.) False Positives and Negatives Most medications, including birth control pills and antibiotics, do not affect the results of pregnancy tests. Alcohol and illegal drugs do not affect the test results either. The only drugs that can cause a false positive are those containing the pregnancy hormone hCG in them (usually used for treating infertility.) Some tissues in a non-pregnant woman can produce hCG, but the levels are normally too low to be within the detectable range of the tests. Also, about half of all conceptions dont proceed to pregnancy, so there may be chemical positives for a pregnancy that wont progress. For some urine tests, evaporation may form a line that could be interpreted as a positive. This is why tests have a time limit for examining the results. Its untrue that urine from a man will give a positive test result. Although the level of hCG rises over time for a pregnant woman, the quantity of hCG produced in one woman is different from the amount produced in another. This means some women may not have enough hCG in their urine or blood at six days post-conception to see a positive test result. All tests on the market should be sensitive enough to give a highly accurate result (~97%-99%) by the time a woman misses her period.

7 Tactical Fixes for Syntactical Impact

7 Tactical Fixes for Syntactical Impact 7 Tactical Fixes for Syntactical Impact 7 Tactical Fixes for Syntactical Impact By Mark Nichol Writers often miss opportunities to push home a point or spotlight an interesting observation by ignoring or not attending to the effect of cadence and syntax on written communication. Such incidents are like a standup comedian placing a punch line in the middle of a joke. Here are some examples of slight adjustments of sentence construction for maximum impact: 1. â€Å"He argued that the court is hardly a legal entity, for a variety of reasons.† The point of the sentence is buried in its midsection, after which a modifier is tacked on, causing the sentence to stagger to a weak ending. Revise as follows: â€Å"He argued that the court, for a variety of reasons, is hardly a legal entity.† 2. â€Å"The Chinese were growing lettuce by the fifth century BC, where it represented good luck.† Because â€Å"the fifth century BC† could be treated grammatically as a location, the second clause could be misunderstood to refer to the time, not the place, which is furthermore only weakly implied by â€Å"the Chinese.† Strongly link the superstition to the people, rather than the country: â€Å"The Chinese, who considered lettuce a symbol of good luck, were growing it by the fifth century BC.† 3. â€Å"More than 600 schools or school districts nationwide have blocked the Web site, according to cofounder John Doe. Doe, who started the site . . .† â€Å"According to† attributions are often stronger at the head of a sentence. This revision also avoids the clumsy repetition of Doe’s name at the end of one sentence and the beginning of the next: â€Å"According to cofounder John Doe, more than 600 schools or school districts nationwide have blocked the Web site. Doe, who started the site . . .† 4. â€Å"Asquith recognized that the majority of his party wanted to steer clear of the approaching conflict- and, more to the point, a majority of his Cabinet.† Wait the majority of his party wanted to steer clear of a majority of his Cabinet? Huh? Well, that’s what it says. But that’s not what it means. Here’s what it means: â€Å"Asquith recognized that the majority of his party- and, more to the point, a majority of his Cabinet- wanted to steer clear of the approaching conflict.† So write it that way. 5. â€Å"Yo-yos were first used as deadly weapons, not as toys.† The mildly startling fact about the toy’s origins is best held back until the end of the sentence: â€Å"Yo-yos were first used not as toys, but as deadly weapons.† 6. â€Å"The model takes the social systems surrounding the alcoholic as crucial, most often the family.† The specification of the primary social system should immediately follow â€Å"the alcoholic,† the focus of the sentence, rather than being buffered and weakened by the additional phrase â€Å"as crucial†: â€Å"The model takes the social systems surrounding the alcoholic, most often the family, as crucial.† 7. â€Å"There, it’s become fashionable to hate Jews, as they are the proxies for Americans in the Middle East, some say puppets.† As the sentence is written, the last phrase seems a muttered aside, rather than a key component of the statement. Inserting it, enclosed in em dashes, in the middle of the sentence gives it the prominence it needs: â€Å"There, it’s become fashionable to hate Jews, as they are the proxies some say puppets for Americans in the Middle East.† Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Grammar category, check our popular posts, or choose a related post below:English Grammar 101: All You Need to KnowComma Before ButForming the Comparative of One-syllable Adjectives