Home pregnancy tests are made to detect the human chorionic gonadotropin (hCG), the pregnancy hormone produced by the fertilized egg in your body. Nowadays, there are numerous different types and brands of pregnancy tests, but they all function in the same way at the end of the day.
Types of Home Pregnancy Tests
Each pregnancy test kit consists of one or multiple sticks in the package. They all have a window that shows one or two lines, depending on the outcome, after 1-5 minutes, as stated in the instructions.
The tip of the home pregnancy test absorbs urine and analyses it for the hCG-H or beta hCG. You can place some tests under your urine stream while others need to be dipped in a cup of urine.
To avoid the mess, home pregnancy tests have a dropper that comes with the package. You take urine with the dropper and drop it onto the designated test stick. The rest of the pregnancy process remains the same.
There are also individual paper testing strips you can buy instead of a home pregnancy test. These are the same strips that are inside the home pregnancy test but without the plastic around them. You can dip one in a cup of urine and wait for the outcome.
Lastly, there are home pregnancy tests in a powder mix that need to be combined with urine to produce a result. These are the rarest types as they are messy and not always as predictable as the previous pregnancy tests.
It is important to note that even though all pregnancy tests function similarly, it is still possible for specific brands and manufacturers to have separate instructions that need to be followed. As such, you need to read the directions first before trying to take a pregnancy test.
That way, you minimize possible user errors and ensure that you get the most accurate outcome.
How Does a Home Pregnancy Test Work?
The female body produces the hCG after the fertilized egg implants in the uterus. This will occur about 6 to 7 days after conception, although it will depend on each specific case. Then, as time passes, the pregnancy hormone content doubles every second day, which is why it’s easier for a test to detect a pregnancy later on in the cycle.
Right now, the demand for high-sensitivity tests is increased as women want to know whether they are pregnant or not as soon as possible. This is why most tests on the market guarantee accurate outcomes, even on the first day of your missed period.
Some claim to detect pregnancy even 6 days before the expected period when everything is done correctly.
Still, the most accurate results come 3 to 7 days after a missed period. By that time, the hCG had increased enough to be reliably detectable with any test. Of course, if you want to find out sooner or you want to be sure of the outcome, you can always do a blood test too.
Determining Test Efficacy: Lab Analyses
Although pregnancy tests are pretty accurate and reliable these days, sometimes, their claims can be somewhat misleading. Namely, many brands state that their tests are 99% correct on the day of a missed period, even though that is not what those tests are lab tested for.
We found a study that the University of New Mexico published. Their researchers concluded the amount of hCG in the urine on any given day after implantation can vary significantly. This means that every woman can have varying amounts of it. Some that have higher will get accurate results from the tests on the first day of their missed period. However, some who have naturally lower hCG will get a false-negative result and have to retest later on in their cycle.
To get the right pregnancy test for you, you need to check which brands can detect 12.5mIU or even down to 10mIU, as this is the amount that women usually have that early in the process.
They tested the brands on the first and second day of the missed period as well, and then they got slightly more accurate results than when testing on the 5th or 6th day before the expected period.
How to Pick the Right Pregnancy Test?
As the lab analyses stated, the more sensitive the test, the earlier you can get an accurate result. This is correct unless a woman has had a leftover hCG in her system from a recent birth or miscarriage or fertility drugs.
In this case, choosing a less sensitive test will be the wiser option because it may give you a false-positive outcome.
Tests will have a certain amount of mIU concentration stated on the package. Some have 10mIU, some detect at 25mIU, and some even at 40mIU. If you want to get the most sensitive test out of all those, you should pick the one with the lowest number possible.
On the other hand, if you want a test that’s not as sensitive because you are testing days or weeks after your missed period, then taking the one that can identify the pregnancy hormone at 25mIU or 40mIU will do just fine.
The timing of the test makes a considerable difference in its accuracy and results. The accuracy of over 96% at most times can only be met if the woman tests at least a week after her missed period. On the other hand, if testing only on the first day of your missed period, you might get an incorrect negative result. But it is still possible that your body produces enough hCG by that time so that a test can detect it.
No matter the case, it is best to take a test and retake it, later on, to be sure of the results.
Reading the Pregnancy Test Results
All line tests for pregnancy testing have one line for Not Pregnant and two lines for Pregnant.
Digital tests, on the other hand, will have the outcome written in letters. This allows for a better interpretation of the result, hence explains their recent popularity.
Additionally, the digital pregnancy test eliminates the possibility for an evaporation line that may appear in the line tests and give you false hope that you are pregnant.
Interpreting the Results
There are two possible outcomes when taking a pregnancy test. You are either pregnant or not pregnant. That seems pretty simple, right? Well, it depends on the situation.
Many women are left utterly confused at their negative result even though they thought they felt all the early pregnancy symptoms. The same happens with women who had gotten a false-positive outcome. They may not have any signs or even actively try to conceive, but the test shows otherwise.
Here are possible reasons for the two outcomes.
Negative Test Results
If you get a negative result, apart from truly not being pregnant, it could mean any of the following:
- You didn’t test first thing in the morning or drank too much liquid before testing. With the morning urine, pregnancy tests are most likely to produce a correct result. This is why you should always test first thing in the morning when the hCG content is the most concentrated.
- You tested too soon. If you tested 5 or 6 days before your period or even sooner than that, you should expect to get a false-negative as the hCG content isn’t as high yet. For the most accurate results, test again at least 1 day after your missed period or even 7 days after. Home pregnancy tests are most likely to detect these levels.
- You waited too long or too little. If you timed incorrectly and waited too little, it is possible that you got a false-negative since the test was still analyzing your urine for hCG. Pregnancy tests need to be read on time. Otherwise, the pregnancy line will fade after 10 minutes.
If your period still hasn’t started and it has been a week since the negative result, you should retake the home test. At that point, if you are pregnant, the pregnancy test will be positive. If not, then make an appointment with your healthcare professional to determine the cause of your condition.
Sometimes stress, too much exercise, hormonal imbalances, or illness can cause you to miss a period.
Positive Pregnancy Test Results
When you take a pregnancy test, and it produces two lines or a result that writes Pregnant, it means you are pregnant. However, false-positive pregnancy tests may happen if:
- Your doctor gave you prescription medication that contains hCG levels, the pregnancy hormone, such as Pregnyl, A.P.L., Profasi, Chorex, Novarel, or Ovidrel.
- Promethazine is used as an antihistamine to treat allergy symptoms. With it, you can also treat nausea or vomiting from illness or motion sickness.
- You have traces of blood in your urine when you take a pregnancy test.
- The pregnancy test was expired or damaged. Avoid buying pregnancy tests at grocery stores. Instead, always opt for drug stores.
- You are taking diuretics that may alter the pregnancy test result and show false hCG levels.
- You had a chemical pregnancy that produces the hCG in your urine and blood and produces a false positive result test. You need to immediately see your doctor and check this condition because it may be dangerous to your health.
Pregnancy Test Accuracy Conclusion
Urine tests have come a long way from accuracy of 60% to over 96% nowadays but still need you to follow instructions and test with care to produce the most accurate results.
If you are sure you are not pregnant but keep getting a positive pregnancy test or vice versa, it is time to see your doctor. Blood tests can confirm or negate a pregnancy or detect a lot of health issues. Such a test is the most reliable way to detect and track your health and the health of your upcoming baby.
After all, if the test is positive and accurate, then finding out as soon as possible will enable you to take prenatal care and take better care of your health and the health of your baby.