Home pregnancy tests (HPT) are diagnostic kits used to determine whether or not a woman is pregnant, and they can be used right from the privacy of your own home. Though they’re not difficult to use, the at-home testing kits do require some know-how if you want to achieve correct results.
Pharmaceutical companies have now invested millions to develop accurate and easy to use HPTs, the reason being they didn’t historically have the best reputation. When first launched in the seventies, home testing kits weren’t known for being accurate, giving many false readings and subsequent ruffled reactions. They were also sensitive to movement and took hours to react.
Today’s tests are considered almost as reliable as a doctor’s blood test. Replacing early versions of tests that required you to mix chemicals and wait for hours - contemporary versions have made it as simple as peeing on a stick, waiting for 5 minutes, and watching the indicator strip reveal the big news.
HPTs have become convenient, affordable, and allow the woman to be confident in the knowledge that she’s pregnant. Since modern HPTs can give results sooner than ever before, they also provide women who are pregnant with the earliest opportunity to cut out potentially harmful behaviors like alcohol consumption, smoking and drug use.
HPTs use urine or blood to measure the presence of a hormone called ‘human chorionic gonadotropin’ (hCG), which is produced by the placenta after the egg has been fertilized; hCG becomes elevated when a woman is pregnant, with concentrations in the blood doubling every two to three days.
The question on most peoples’ minds when they’re considering an HPT is, “How soon will I know if I am pregnant?” Certain home pregnancy tests claim to detect concentrations of the pregnancy hormone as early as 25mlU/ml, which usually occurs approximately ten days after ovulation (or four days before the time you’d miss your period). Other home testing kits won’t test positive until hCG is 50 or even 100mlU/ml. Users should keep these figures in mind when choosing a brand and selecting a day to execute it.
Home pregnancy tests have become a popular and reliable diagnostic tool in determining pregnancy status. In the United States alone, over 33% of women have used an HPT to ascertain their pregnancy status before seeing a health care professional. Thankfully, studies have shown that the accuracy and efficiency of home pregnancy tests is now 97.4%, almost as high as professional laboratory testing.
Although tests exist that can detect pregnancy before your period is due, an indication of ‘not pregnant’ may not be accurate. Despite a negative result, it is recommended that women monitor for signs of pregnancy anyway; this allows some leeway for things like late implantation or delayed ovulation. It is also important to know that testing is more likely to be correct when a positive result is obtained!
The two most common reasons why false negatives occur are:
The best way to avoid false negatives is to increase the probability for accuracy. In order to achieve that, explore the various HPT options, find one that is most suitable to your needs (e.g. ease of testing, hCG sensitivity), and follow the manufacturer’s advice exactly. A few other ways to increase accuracy include the following:
A false positive can also show in women who have taken hCG - as part of an infertility treatment program, or for any other reason. In a case like this, it can take two weeks for the hormone to completely clear your system. Another reason for a false positive is when a woman has recently experienced a miscarriage or an ectopic pregnancy; hCG levels can take up to four weeks to drop to normal range in these circumstances.
Of the 30 or so HPTs on the market, home pregnancy kits range from highly sensitive to less sensitive. Once fertilization has taken place, the test that measures the lowest amount of hCG will give the earliest indication of pregnancy. Despite the fact some companies promise the earliest of detection rates, a good rule of thumb is to expect not to have a positive result until at least the first day you miss your period.
When it comes to pregnancy most HPT users are anxious to know the results, but since accuracy is of utmost importance it’s important to be patient and wait the recommended length of time to get the right answer.