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Modern pregnancy tests allow you to determine it even in the early stages. However, this does not mean that a test can give a positive or negative result immediately after intercourse. To determine on what day after conception the test can give a reliable result, you need to know the design of these devices, navigate in their types and understand what this or that sensitivity threshold means. The fact is that some devices can determine pregnancy at an earlier date, while others show the result only on the first day of a missed period. Therefore, before conducting a study, it is necessary to collect some information about testing systems.
How are pregnancy tests designed and how do they work?
All pregnancy tests have a fairly simple principle of operation. They are equipped with special indicators that notify a woman of an “interesting situation”. It is very easy to conduct a study and evaluate the result at home. Any test has a reagent that is sensitive to human chorionic gonadotropin. This hormone begins to be produced in the body of a woman immediately after conception, but its level in the urine rises gradually. It is urine that will be required for the study. When it accumulates the concentration of the hormone that allows the test to react, it will give a positive result. Accordingly, when there is little hormone in the urine, the test response will be negative.
A reliable result can almost always be obtained on the first day of a missed period. All test manufacturers indicate that the accuracy of their devices is 99% if the testing procedure is carried out within the specified time frame and the instructions are strictly followed.
Many modern testing systems make it possible to determine pregnancy a few days before the expected start of menstruation, but this does not mean that conception can be diagnosed already 1-2 days after intercourse. The hCG hormone begins to be produced in large volumes only a week or more after the egg has been fertilized. At the same time, the level of gonadotropin in the urine 7 days after conception will still be insufficient for the test to give a positive result. However, starting from next week, the level of hCG increases several times and using tests with increased sensitivity to this hormone, it will be possible to determine the presence of pregnancy.
On what day of pregnancy do different types of tests show conception?
Now on the market there are several types of tests that allow you to determine pregnancy in the early stages. They have a single principle of operation, but the information content and accuracy of the results obtained, depending on the type of device, are somewhat different.
How long does a test strip indicate pregnancy?
A test strip or strip test is the simplest and most affordable device that allows you to determine pregnancy in the early stages. To conduct the study, you will need to lower the test into a container with urine to the mark and hold it there for 10 seconds. Then the device must be removed from the urine and left for three minutes alone. After this time, the result is evaluated. Two lines that appear on the test indicate the presence of pregnancy, and one line indicates its absence.
Although test strips are very popular among the female population, they have a number of disadvantages. One of these is the possibility of diagnosing pregnancy only from the first day of delayed menstruation. This means that a woman will need to know exactly the date on which her menstruation should begin, since before that it makes no sense to conduct a study. The result will be invalid. This problem is especially relevant for those women who have an unstable menstrual cycle.
The sensitivity of test strips is at the level of 25 mIU/ml. Such a concentration of the hCG hormone in the urine of a woman is not always achieved even on the first day of a delay in menstruation, since individual characteristics of the body should be taken into account. Therefore, despite the assurances of manufacturers that their tests determine pregnancy on the first day of a missed period with an accuracy of 99%, in fact, this percentage equates to 90%. In the future, on the second and third days of delayed menstruation, the reliability will increase. As statistics show, it is possible to determine pregnancy with an accuracy of 99% using a test strip only on the seventh day of a missed period.
Another disadvantage of strip tests is that a reagent designed to confirm pregnancy is applied to a paper or fabric layer. When trying to determine pregnancy in the early stages, the result may be unclear, that is, the band often turns out to be either blurry or dim. This misleads most women, makes them nervous, goes to buy a new pregnancy test, wastes time, their own money, etc.
Nevertheless, all the obvious shortcomings of test strips can be forgiven for their low cost and a fairly high percentage of reliability, especially when conducting a study starting from the first day of a missed period.
How long does a tablet test show pregnancy?
The tablet test is the most accurate rapid test device available on the market today. It allows you to determine pregnancy in the early stages even 2-3 days before the delay in menstruation.
The fact is that the study using the tablet test is as close as possible to the diagnosis in the laboratory. For analysis, a few drops of urine are introduced into the urinal, which is available on the tablet test. This is done using a special pipette, which is always included in the kit. The reagent inside the test interacts with the incoming urine, after which the result appears in the control window.
The sensitivity of tablet tests is 10-15 mIU/ml. This rather high threshold for determining the hCG hormone in the urine, which provides women with the opportunity to diagnose pregnancy a few days before the expected start of the next menstruation. It is very convenient to use such tests for women who have an unstable cycle. In this case, you do not need to know, with an accuracy of one day, the date of arrival of the next menstruation.
However, such devices have their drawbacks. The first of these is a higher price compared to strip tests. The second disadvantage can be considered the low level of reliability of the results of the study when it is carried out at too early stages of pregnancy.
If on the first day of a delay in menstruation, the accuracy of the result obtained is equal to 99%, then on other days it has the following threshold:
1 day before the onset of menstruation – 98%.
For 2 days – 97%.
For 3 days – 90%.
For 4 days – 66%.
These indicators must be taken into account in early research. When a woman does not know the timing of the next menstruation, device manufacturers advise testing no earlier than 19 days after a possible conception.
How long does an electronic inkjet test show pregnancy?
Electronic tests are the most modern and most expensive devices for early diagnosis of pregnancy. However, their high price is justified by the accuracy of obtaining the result and its unambiguous interpretation. Moreover, electronic tests are much more informative than test strips.
It is very simple to carry out the testing procedure, it is enough to substitute the test under a stream of urine, hold for 5 seconds, and then evaluate the result. It is convenient that the test gives it out in words or characters, and not in stripes. Moreover, the answer is displayed on the electronic scoreboard.
The sensitivity of most electronic tests starts at 10 mIU / ml, which allows you to conduct a study already 5 days before the onset of menstruation. As for the accuracy of the result obtained depending on the day of the study, it is similar to the percentages that are typical for tablet tests.
An important advantage of the electronic test is that it allows you to determine the gestational age in weeks. Moreover, there are modern devices equipped with a USB port on the market. This makes it possible to connect the test to a computer. Depending on the selected device, it may contain information about the presence or absence of pregnancy, as well as its duration in weeks. Learn more about what a digital test is ➤.
On what day after intercourse can a test show pregnancy?
Of course, if a woman suspects that she may be pregnant, she is eager to find confirmation of her assumption. But be that as it may, you need to understand that the level of hCG cannot rise at one moment, since all processes in the body go smoothly and gradually. In the blood, the level of the hormone is always much higher than in the urine, so the timing of determining pregnancy using a test is somewhat remote.
So, with the help of a standard strip test, it will be possible to find out about your position no earlier than 11-15 days after ovulation. If the sensitivity of the test is high, for example, as with electronic devices, then you can find out about your position a little earlier – about 8-10 days after the release of the egg from the ovary. At the same time, it is not worth counting on an undoubtedly accurate result.
It should be noted that the result of a pregnancy test can be both false positive and false negative. This can happen for a number of reasons. For example, the test may not show an existing pregnancy if the study was carried out too early, or immediately after conception there is a threat of miscarriage. A false positive result is a consequence of a woman taking hormonal drugs or the presence of a hormone-producing tumor in her body. Failure to follow the instructions for use can distort the test results. The test may not work even if its expiration date has expired, or storage conditions have been violated.
If a woman knows exactly the date of ovulation, then a test with a sensitivity of 10 mIU / ml can be performed 7-10 days after unprotected intercourse. In this case, the lower the sensitivity threshold of the device, the less reliable the result will be. If a woman doubts whether the device worked correctly, then you can repeat the testing procedure after another 2-4 days. The best time to take a pregnancy test is the first day of a missed period.
When the test gives a positive result, in which the woman is sure, it is necessary to contact a gynecologist and undergo additional examinations. If the test results are negative, and menstruation does not start on time, then a visit to the doctor’s office is also mandatory.
[Video] Obstetrician-gynecologist Zhukova O.Yu. answers the question – how many weeks after intercourse can a pregnancy test be done?