How does a pregnancy test work? Test strip: principle of operation. False positive pregnancy test result. Jet pregnancy test

After conception, the woman’s body gradually increases in blood pressure, which produces trophoblast cells - these are the precursors for the formation of the placenta. Thanks to its presence in urine, early diagnosis of pregnancy can be carried out.

The test can be carried out already after the second day of missed period.

But many women who are faced with this issue for the first time do not know how to choose such a remedy, how to use a pregnancy test and how to avoid mistakes?

Mechanism of action

The standard test that determines the presence of human chorionic gonadotropin in the urine has two strips - control and diagnostic.

The first one works if any moisture gets on the surface.

A diagnostic strip has special substances (antibodies) that react to the presence of hCG in the urine.

During direct contact of chorionic gonadotropin with labeled antibodies, the diagnostic strip becomes red.

Buying a pregnancy test

Buy tests only in pharmacies. This will help you avoid purchasing a low-quality fake.

When purchasing a pregnancy test, check the integrity of the packaging. The strip should be packed in thick cellophane. Sometimes it is filled with air.

If the expiration date of the product has expired or you find damage to the packaging, then there is no point in doing such a test - the result will be unreliable.

Studying a wide range of pregnancy tests, you see in front of you the products of various companies and different price range. But the reliability of the result does not depend on the manufacturer and cost. Is it true, more expensive tests respond even to the lowest dose of human chorionic gonadotropin.

That's why, if you can't wait to find out the answer to a question whether you are pregnant or not, but only a couple of days have passed since your missed period, give preference sensitive test . Thanks to him, the situation will certainly become clearer.

When to take a pregnancy test?

If you want to achieve maximum accuracy in diagnostics at home, in the evening, on the eve of the test, do not eat fatty foods and refuse sexual contact.

It is advisable to use the test strip in the morning, taking the first urine of the day for research.

Do your research only before meals. After eating, the answer will be untrue.

It is at the beginning of the day that the concentration of the hormone is highest and the result will be the most accurate. Therefore, immediately after waking up, go to the toilet.

Collect the urine in a container and lower the tip of the test strip into the urine to the indicated mark, holding it there for a couple of seconds. After this, place the test on a horizontal surface.

The result will be ready in 5 minutes. After 10 minutes the test is considered void.

Two stripes indicate that conception has occurred. But it is worth considering that positive result may occur even in the absence of pregnancy. This mainly occurs due to hormonal imbalance in the body.

To find out exact result , it is better to go to a gynecologist after the test, who, after examining the uterus, will be able to determine whether pregnancy has occurred.

Sometimes on early dates, If gynecological examination was not indicative, an ultrasound examination or tests are prescribed.

But even if the second line appears faint and barely noticeable on your test, most likely you are pregnant. You can additionally use a couple more tests from other manufacturers.

Remember, in some cases, hormone production begins not on the 6th day after conception, as usual, but on 14-15.

This is the period of maximum concentration of human chorionic gonadotropin. Therefore, if the test result is negative and there is no period, there is a reason to wait a few more days and repeat the study, which next time, perhaps, will tell you the long-awaited answer.

Varieties of tests

strip strip– the most common type of pregnancy test. This is a thin strip with a reagent inside. Using this test, it is determined human chorionic gonadotropin person in the urine. Open the package immediately before use.
tablet test- this is an analogue adapted to home conditions laboratory diagnostics pregnancy. It gives the most accurate result. It differs from test strips in that it does not need to be immersed in a container with urine and this product is more reliable because it is protected in a plastic box. You should take a portion of urine into a disposable pipette and insert 4 drops into the special window of the test cassette where the reagent is applied.
Electronic test. The method of application is identical to the tablet and conventional tests. But in this case, under the influence of human chorionic gonadotropin, no colored stripe, and the inscription “pregnant” or “not pregnant”.
- this is the most reliable method early definition pregnancy at home. This product has a more sensitive reagent. This affected its cost, which is higher than the price of tablets and test strips. You can find out about the onset of conception 4 days before the start of menstruation. Jet test It is especially convenient because you do not need a container to collect urine.

Remove the cap from the cassette and grab the test in the place where there is a mark in the form of an arrow. You need to place the marked tip, which was under the protective cap, under a stream of urine for a few seconds and then close the test with the cap.

The result according to the standard will be ready in 5 minutes and will become invalid after 10 minutes.

The study can be carried out at any time of the day, because a very sensitive reagent detects the presence of human chorionic gonadotropin, regardless of its concentration level. But follow the instructions as precisely as possible, otherwise the result may be false.

False positive pregnancy test result

False positive result - this is the case when the test shows 2 stripes in the absence of pregnancy.

In low-quality tests this can happen: that the dye will split off from the conjugate before the entire antibody-hCG-dye complex reaches the reaction zones.

This is how blurry spots appear. This result is often mistaken for a “false positive”. But true false positives are extremely rare.

Besides, a faint second stripe appears, if the test is “overexposed”, that is, study the readings after 10 or more minutes.

A similar line is formed due to the evaporation of water from the surface of the dough. This destroys the conjugates, which release the dye.

It is precisely because not every woman strictly follows the instructions and incorrectly interprets the test result that doctors, especially old-school gynecologists, do not trust too much early diagnosis pregnancy carried out at home.

A false positive response may be caused by taking specific medications, kidney problems, or due to large quantity drunk liquid.

Sometimes this result indicates about the presence of a trophoblastic tumor. Some gynecological diseases may provoke increase in the level of human chorionic gonadotropin and in order to exclude them, it is necessary to contact a gynecologist after a positive test result.

If you were given hCG to maintain the luteal phase(preparations Pregnil or Profazi), then traces of this hormone remain in the body for 10 days after the last dose of the medication. Therefore, a pregnancy test in such cases gives a false positive result.

False negative test

There are times when tests give false negative. This happens much more often than cases with a false positive result.

A false negative test is characteristic of too early research or for a low-sensitivity test.

With a pregnancy that is on the verge, human chorionic gonadotropin will not be produced as intensively as during a normally developing pregnancy.

Anyway a pregnancy test allows women not to run to the doctor at the slightest delay, but first check at home and only then consult a doctor to clarify the results.

It is after this that we can clearly speak about the presence or absence of pregnancy.

Literally twenty years ago, to determine pregnancy, a woman needed to “shake” for a couple of months in anticipation, visit the doctor several times and take tests. Today, progress has simplified this procedure, and pregnancy can be diagnosed in just a minute.

Every woman at least once in her life has encountered a delay in menstruation and asked herself the question: “Am I pregnant or not?” And I wanted to find out about this as soon as possible, without waiting for the first signs of pregnancy to appear. Get an answer today exciting question can be done quite quickly, and for this you need to buy a modern pregnancy test at the pharmacy, which allows you to determine with high accuracy whether a pregnancy has arisen in your womb new life or not.

There are a huge number of tests for quickly diagnosing pregnancy, differing in price and type, but their operating principle is the same.

Before using express diagnostics, you need to know the answers to important questions:

what types of tests are available in the pharmacy;
when to do the test;
how to correctly interpret the result;
which test is better to give preference to?

We will talk about this in our article.

A little about the physiology of the “pregnant” female body

The operation of all pregnancy tests without exception is based on determining the presence of hCG, the human chorionic gonadotropin hormone found in the urine. An egg that has been fertilized is implanted into the wall of the uterus, and during its development, production occurs hCG hormone. A woman should know that after conception, already on the 7-8th day, this hormone, secreted immediately after conception by the fetus itself, can be detected in the urine, so if you suspect that you are pregnant, feel free to use the test without waiting for the date of your expected period. It is this hormone that causes the reaction of the test.

What is a pregnancy test and how does it work

Home rapid test or pregnancy test - simple, but proven and sufficient reliable way find out about pregnancy even before your period should come. Statistics show that the reliability of the test is in the range of 97%-99%, and this is very high performance. Let's figure out how a seemingly ordinary, simple device gives such a result about the most long-awaited event in a woman's life - her pregnancy.

A reagent containing antibodies to the hormone human chorionic gonadotropin is applied to the outer surface of the test. If a woman is in " interesting position”, then when using a rapid test, antibodies begin to enter into active interaction with urine. If we use a paper test strip, then it has an absorbent part with a dye, and after immersion in urine it turns a certain color. If the hCG hormone is present in the urine, that is, the woman becomes pregnant, then the test strip releases the dye, and two blue or crimson lines clearly appear on its surface.

Depending on the level of concentration of the mentioned hormone in the urine, the second strip can be of medium color saturation or quite bright. If conception has not occurred, then the second line will not be colored, that is, it will not appear, and you will see only one stripe. This means that the test result is negative. The first strip contains a dye reagent, and it is always released upon contact with urine, and this process does not depend in any way on the presence of human chorionic gonadotropin in it.

It is important to know! If you see a faintly colored second line on the test, you should assume that you are pregnant.

A strip immediately appears in the diagnostic zone of the test red-pink color, and there will also be a stripe in the control zone of the test - the woman will see two red stripes, indicating pregnancy. If during the diagnosis there is only one line in front of your eyes, then you can say with confidence that conception has not occurred and you are not pregnant.

What pregnancy tests are there: types of tests

Today at a pharmacy a woman can choose several types of pregnancy tests:

test strips;
inkjet tests;
tablet tests.

Test strips

Test strips are the most affordable and are very popular among the fairer sex.

It is very easy to use: you will need to collect urine in a clean, dry container, after which the test strip is lowered into it to the indicated mark for 20 seconds. Now you need to wait 3-5 minutes, and the result will be before your eyes.

Inkjet tests

The second type of tests is inkjet tests. This is the most convenient type of test when compared with the other two “brothers”. No containers are needed, and the woman only needs to insert a strip of dough while urinating.

You don't have to wait for the result, as it will be almost instantly.

Tablet tests

Tablet tests, as the women themselves say, are the most reliable. This opinion is based on the fact that in this test the reagent is protected by a plastic box.

To use this test, you need to collect urine in a dry, clean container, and then, using a special pipette that comes with the test, you need to drop a small amount of urine onto the window of the tablet test. You will also have to wait about 5 minutes.

Pros and cons of pregnancy tests

The tests listed above have both pros and cons, and the woman herself must choose which one is most suitable for her.

Test strips

Test strips are famous for their low cost and impressive range in pharmacies. Among the disadvantages are the following:

inability to use outside the home, as a container is required to collect urine;
the carrier of the reagent is paper - a short-lived material that can deteriorate and not give one hundred percent result
the sensitivity of the test has limitations - the indicator of the required level of the hCG hormone is 25 mIU / ml, which in some cases is not relevant.

Tablet test

The tablet test has an undeniable advantage - when using it, it does not need to be lowered into the urine. The kit includes a convenient pipette.

Negative points:

the price is higher than available test strips;
You need a container to collect urine. That is, it is difficult to do it at work or outside the home.

Inkjet tests

Inkjet tests have the following advantages:

easy to use both at home and at work;
no need to look for a container to collect urine;
the result is almost instant.

Among the minuses - enough high price.

When can a pregnancy test be false?

There are times when the test showed false negative result. What is it, and how is it to be understood? Such a question may disturb a woman if she observes changes in her body, feels signs of pregnancy, but the test shows a negative result. Such a result, according to statistics, can be found much more often than the opposite - a false positive.

The reason lies in the untimeliness of testing. Simply put, a woman makes a diagnosis on the first day of menstruation, which did not come due to the fact that pregnancy did not occur, or there is panic fear that this happened.

And the reason is that the manufacturer guarantees the correct answer in the test only if there is a certain amount of the human chorionic gonadotropin hormone in the urine, and if you read the instructions, then the figure is written there - at least 20-25 mIU / ml. If we talk about blood, then the indicated concentration of the hormone will be only 7-10 days after the fertilization of the egg, and every two or three days its concentration becomes twice as high. And if we talk about the urine with which the test is done, then it will contain half as much human chorionic gonadotropin, so a home test is best done 12-15 days after the day when the woman assumes that she is pregnant.

Important! To get the most accurate result, do the test after a delay of menstruation by 3-4 days.

Other reasons may also affect the test result. Eg, false negative test may be influenced by the following factors:

The woman has a history of illness of cardio-vascular system or kidneys, which may interfere with the release of hCG in the amount necessary for testing;
the woman had an ectopic or missed pregnancy. Test in this case will not confirm pregnancy, since the concentration of the hormone, both in the blood and in the urine, is reduced.
before the test, the woman drank a lot of diuretic fluid;
pregnancy is at risk. IN this state the level of the mentioned hormone in the urine drops to a minimum level, so the test will not give the correct result.

False positive home pregnancy test result

I would like to immediately reassure women and assure that this kind of result is extremely rare and can be influenced by such reasons:

an ectopic pregnancy was removed or the woman had an abortion;
a false pregnancy test can also show in postpartum period, a few days after the birth of the baby;
a woman is taking hCG drugs. She will see two lines on the test for another 10 days after the last hormonal pill was taken;
if a woman has trophoblastic tumors in her body that produce the specified hormone.

It is important to know! It happens that the unreliability of the results lies in the fact that a low-quality test was used or its expiration date has expired. False results can also be caused by using the test in a manner inconsistent with the instructions. For example, a woman incorrectly (not deeply) lowered it into a container with urine. To avoid unreliable results, before using the test, carefully study the instructions included with it, and then follow the necessary steps step by step.

In conclusion, I would like to say that the choice of test to determine pregnancy is made by the woman herself, both in terms of price and ease of use. But in any case, only a doctor after medical research can accurately answer whether there is a pregnancy or not.

Previously, literally a couple of decades ago, in order to find out for sure whether pregnancy had occurred or not, you had to wait at least two months, visit the doctor several times, take tests and monitor the dynamics. Now, with progress that is moving forward by leaps and bounds, everything has become so simplified that literally in the very first weeks it is quite possible to find out about your pregnancy. Today there are special tests for this.

Let's try to understand the operating principles of this small device - a pregnancy test.

How a pregnancy test works

A pregnancy test or is a fairly reliable and simple way to find out about your pregnancy in the first weeks after conception. The reliability of the result, according to statistical data, is ninety-seven to ninety-nine percent. How can a small and seemingly simple device give results about such a complex and important process as the birth of a new person in the womb?

Here it is worth delving into physiology female body. One of the most early signs successful conception is the appearance in the blood and urine expectant mother a hormone called human chorionic gonadotropin, or hCG. This hormone begins to be released by the fetus itself immediately after conception. It is this hormone that gives the test reaction.

The test has an absorbent part with a substance (dye), which, when immersed in liquid, turns a certain color. That is, if there is a woman in the urine, the test strip releases the dye and two crimson or blue lines become visible. This is a positive pregnancy test response. The second or lower line may be bright or medium in color, depending on the concentration of the hCG hormone in the urine. In the absence of the hormone in a woman’s urine, the second line does not stain or appear, which is a negative test response.

The first line contains a dye reagent, which is always released upon contact with liquid, and does not depend on the presence of human chorionic gonadotropin in it.

False negative pregnancy test result

What is a false negative pregnancy test result? This question may arise when a woman feels all the signs of pregnancy, but the test does not show it. This result, according to statistical studies, occurs several times more often than the opposite, false positive.

The reason for this is the lack of timely testing. That is, a woman begins to conduct a test on the first day of menstruation, which has not begun due to panic fear of pregnancy or non-occurrence.

The fact is that manufacturers guarantee the correct test answer if there is a certain amount of human chorionic gonadotropin in the urine. The instructions indicate that it should be at least twenty to twenty-five mIU/ml. The hormone can reach such a concentration in the blood only on the seventh or tenth day after conception, and then, every two to three days, it doubles. But it's blood. But urine, as a rule, contains half the amount of this hormone, and therefore testing should be carried out only twelve to fifteen days after the expected conception.

That is, in order to get the most correct answer, you need to be tested approximately on the third or fourth day after a missed period.

But, there are other causal factors that affect the test result. So a false negative result may be due to:

a woman drinking too much water or a diuretic before the test;
the presence of kidney or cardiovascular diseases in women. These diseases can prevent the release of hCG in the amount needed for testing;
threat of pregnancy failure. In this condition, the level of human chorionic gonadotropin decreases to a minimum that is not shown on the test;
frozen or ectopic pregnancy. In this condition, the concentration of this hormone in the blood and urine also decreases, and therefore the test does not show the presence of pregnancy.

False positive pregnancy test result

These kinds of results happen much less frequently. But there are reasons for this:

postpartum period (within a few days after birth, the test may show);
after an abortion or removal of an ectopic pregnancy;
the presence in the body of trophoblastic tumors that produce the production of human chorionic gonadotropin;
while taking hCG drugs. For another ten days after the last data reception hormonal drugs the test will show two lines.

It happens that the unreliability of the results is due to the tests themselves, that is, their low quality of production or use after their expiration date. Also, false results can be given by a test that is incorrectly used, that is, it was not deeply lowered into the liquid (urine). To exclude these causes of false results, before using the test, you must carefully read the instructions and then follow it step by step.

Types of Pregnancy Tests

There are several types of pregnancy tests: strip tests, tablet tests, and inkjet tests.

The first type of tests are the most accessible and popular among women. To use it, it is necessary to collect urine in a clean and dry container, and then lower the strip into it to the indicated mark for twenty seconds. You can evaluate the result in three to five minutes.
The second type of tests is tablet tests they, judging by the reviews, give the most reliable results. This opinion is due to the fact that in this type of test the reagent is protected by a plastic box. For use of this type test, you also need to collect the urine in a dry and clean container, and then use a special pipette (which comes with the test) to drop a little urine onto the window of the tablet test. The result can be assessed in five minutes.
- the third type of device, the most convenient of all other types. There is no need to collect urine to use it. It is enough to place a strip of test under the stream while urinating and you can evaluate the result almost immediately.

Each type of test has its own pros and cons. The choice remains with the woman herself. The advantages of test strips include affordable prices for everyone and a huge selection in pharmacy chains.

But this test has its drawbacks. For example, its sensitivity is limited to 25 mIU/ml hCG; it cannot be carried out anywhere, since it requires collecting urine in a container and the reagent carrier in this case is paper, which cannot give an accurate result one hundred percent.

To the positive features tablet tests include: no need to immerse it in urine, and for complete convenience, a pipette is always included in the kit.

Negative characteristics of this type of pregnancy test include the need to collect urine in a container and its higher cost compared to strip tests.

Inkjet tests have combined pros and cons that are characteristic of both strip tests and tablet-type tests.

Which pregnancy test to choose is up to the woman herself. But remember, complete confirmation of pregnancy or its absence can still only be determined by a doctor after certain studies.

Today, rapid pregnancy tests can be bought at every pharmacy, and even at the supermarket checkout. They are easy to use and reliable: doctors rate their accuracy at 99% Pregnancy Tests. But often such tests lie.

How Pregnancy Tests Work

Absolutely all pregnancy tests check whether there is a special hormone in the urine or blood (if we are talking about a laboratory test) Pregnancy Tests- human chorionic gonadotropin, abbreviated hCG. It begins to be produced immediately after the fertilized egg attaches to the wall of the uterus.

If there is no pregnancy, hCG is nowhere to come from. If it is, hCG will be required.

Typically, the egg attaches to the uterus six days after fertilization. During this period, the test is meaningless: it will not show anything. And here's what's next hCG level increases rapidly, doubling every 2–3 days.

When to take a pregnancy test

Already 8 days after the egg meets its sperm, the hCG level becomes sufficient for pregnancy to be confirmed using a laboratory blood test.

After a few more days - that is, on the 10th–12th day after fertilization - the pregnancy will be detected by ordinary pharmacy tests.

Although the instructions for many of them promise an accurate result already on the first day of the delay, doctors advise not to rush Home pregnancy tests: Can you trust the results?. The reason is simple.

If you ovulate on the 10th–14th day of your cycle, then by the beginning of the next cycle at least 13 days will have passed since fertilization. This means that the test will signal you with two stripes.

However, ovulation may shift. If the egg was released on the 22nd day of the cycle, then by the beginning real time pregnancy may be less than 7 days. This means that even perfect tests, most likely, nothing will be recorded.

If your cycle is more or less than 28 days, things are even more confusing.

Therefore, in order to get the most accurate result, you should wait 5–7 days from the start of the delay.

If you are pregnant, the hCG level by this time will in any case be such that even the cheapest tests with low sensitivity will clearly recognize it

But even if you met all the deadlines, the test can still mislead you. For example, it will not see a high level of hCG and will show a negative result if there is an existing pregnancy, or, on the contrary, it will give two stripes, although it does not smell like pregnancy. To be fair, let's say that the test is not so much to blame as you are yourself Five reasons for false-positive pregnancy tests.

Why do rapid pregnancy tests lie?

1. You used an expired or damaged test

Express tests contain special highly sensitive substances that react to hCG levels. It is they who, when in contact with the urine of a pregnant woman, are painted with a bright second stripe or plus sign.

But if the test is expired or improperly stored, the sensitivity of these substances may decrease. As a result, they will give a negative result, which may turn out to be false.

What to do

Buy tests only in pharmacies, where, unlike supermarkets, they try to provide the right conditions storage When purchasing, be sure to check the expiration date.

2. You bought a test with low sensitivity

The sensitivity of rapid tests is indicated by numbers - 10, 20, 25, 30. These numbers indicate the concentration of hCG in urine (in mIU/ml) that they are able to detect. The higher the number, the less accurate the test. The most expensive and accurate options have a sensitivity of 10. But cheap ones may not detect hCG and deceive you by showing a negative result.

What to do

When purchasing a test, be sure to check with your pharmacist how sensitive it is. Also, this information can often be found on the packaging and always in the instructions.

3. You took the test in the afternoon

It’s not for nothing that in the instructions for the vast majority of tests, the manufacturer talks about morning urine. It is more concentrated, there is more chorionic gonadotropin in it, which means the test will be more reliable.

In the afternoon, the content of hCG in the urine is lower.

What to do

Use the test exclusively in the morning, as the manufacturer instructs.

4. You drank a lot of water before taking the test.

Water dilutes the urine, which lowers hCG levels. The rapid test may not detect the hormone and give a false negative result.

What to do

Try not to eat or drink anything before the test.

5. You didn't look at the results in time.

The instructions for each test stipulate the rules for its use. For example, like this: “The result can be assessed 4–5 minutes after the test, but no later than 15 minutes.” These minutes are not taken from the ceiling.

The lower limit indicates the time it takes for the test to allow the sensitive substances it contains to react to the hCG level. If you look at a test earlier than the agreed upon date, the second line (or the plus sign in the corresponding window) may not yet appear and you will see a false negative result.

If you look at the strip later than that time, which is designated as the upper limit, you risk getting a false positive result. Evaporated urine may leave a line that can easily be confused with the second line.

What to do

Before using the test, read the instructions and follow them strictly.

6. You are taking certain medications

Some diuretics and antihistamines affect the composition of urine, diluting it. This reduces the level of hCG, which means there is a risk of getting a false negative result.

Other drugs, on the contrary, can give you two strips, although in fact they don’t. Such medications include:

some tranquilizers and sleeping pills;
anticonvulsants;
fertility-enhancing drugs.

What to do

If you are taking any medications on this list, you should not rely on a paper rapid test. To determine whether you are pregnant or not, do a laboratory blood test.

7. You are sick

If there is increased blood or protein in the urine, this may also affect the result of the rapid test. But here it is important to note that in itself this situation is extremely unhealthy. Blood in the urine indicates work Bladder or kidneys elevated protein- about internal inflammation.

Therefore, most likely, the erroneous two strips on the test will be attached elevated temperature and/or discomfort in the genital area and kidneys.

What to do

Do not rely on a rapid test if you have a fever or pain in your lower back or lower abdomen. In case of such ailments, you should contact a therapist, gynecologist or urologist as soon as possible so as not to miss a serious illness.

8. You develop an ovarian tumor

Some types of tumors can trick the test into showing two lines.

What to do

Once you receive a positive result, do not delay your visit to the gynecologist. The doctor will conduct research during which he will determine the actual duration of pregnancy (if any) or send you for additional tests and to specialized specialists.

How to take a pregnancy test correctly

Read the instructions. And follow it, of course!
Remember the rule: if you are healthy and the test shows a positive result, the probability of pregnancy is 99%. Negative result may be false up to a week after the delay.
Choose from tests high level sensitivity. 10 is ideal.
Do the test in the morning, not in the afternoon, and especially not in the evening.
Try not to drink at least an hour before the test.
Do not rely on the test if you are taking any of the above medications or if you have fever or lower abdominal pain.
Buy two tests at once so you can double-check the results.
If rapid tests contradict each other, don't wonder what's wrong. Get a laboratory blood test to find out worthy correct result.

Important! positive test, even if you have been waiting for it for a long time, alas, there is still no reason to rejoice. Increased level HCG in the urine can be fixed, including during an ectopic or missed pregnancy. Therefore, after receiving two strips, go to the gynecologist as soon as possible.

The test is the most easy method definitions of pregnancy. There are two main types of pregnancy tests: urine test and blood test. With the help of such tests, you can quickly find out the result, but it must be remembered that only a doctor will give the most correct answer. After all, all physiological features cannot be determined at home, for example, the presence of an ectopic pregnancy or a condition similar to pregnancy, but in reality is a symptom of some disease.

How pregnancy tests work

In a pregnant woman, the placenta initially secretes a special hormone - human chorionic gonadotropin (CG, hCG), which does not allow new eggs to be produced, thus preventing a secondary pregnancy from developing. Early diagnosis (from the first day of missed menstruation) is based on identifying such a hormone. More precisely, the test is designed in such a way that it records a certain amount of hCG in a woman’s body. When the test shows a positive result, it is determined physiological characteristics women. This is possible on the first day of a missed period or after six days. The idea that the test detects pregnancy a day after conception is fundamentally wrong, since only with an increasing concentration of the hormone in the urine can the result really be known. Regardless of the quality of the tests, which determines the degree of their accuracy, a positive result can only be 14 days after ovulation. This is why experts advise testing only after a missed period.

Pregnancy tests that are used at home are mainly urine tests that determine pregnancy. They are very easy to use and at the same time cheap. Most often, such a test is carried out in a small amount of time and provides correct results in 99% of cases. Pregnancy tests can be bought at pharmacies or stores without a doctor's prescription. False positive response is extremely rare, but false negatives may well be common if the test is done prematurely, before development right quantities HCG.

Test sensitivity

There are two types depending on sensitivity:

1. Setting the hCG content from 10 mU/ml. With the help of these tests, it is possible to determine pregnancy on the sixth day after fertilization. It must be taken into account that fertilization occurs later than conception.

2. Determining the content from 25 mU/ml. These tests, of course, are cheaper and can detect pregnancy at a later date.

Test strips

A very popular type of test. To use the test strip, you need to collect urine in a clean container, lower the test for 15 seconds to the indicated mark, and see the result after 4 minutes. When one red line appears on the test, it means there is no pregnancy; when two red lines appear, it means pregnancy.

Tablet tests

It is believed that tablets more precisely strips, since the reagent is closed by a plastic frame. To use the test, you also need to collect urine, and then use the included pipette to drop a little into the window on the test. After 5 minutes, see the result.

Inkjet tests

The most newfangled tests. To use them, you don’t need to collect urine; you just need to hold the test under the stream for a few seconds - and that’s it.

Electronic test

The actions are the same as in other cases, only instead of the stripes the inscription “pregnant” or “not pregnant” appears.

In what cases can the result be false?

The result may be false if:

the test has expired;
there are diseases causing secretion hCG (ovarian dysfunction, tumor, etc.);
used hormonal medications or diuretics.

So, the test result is received

The test should be performed when menstruation is approximately due. After receiving the test result, it is necessary, regardless of the result, to see a specialist. Only a doctor can exclude ectopic pregnancy, A early examination will be a good insurance for the successful development of pregnancy. If the delay continues and the test reveals a negative result, the gynecologist will identify the cause of the menstrual irregularity.

Maximum effectiveness of pregnancy tests

In order for the test to give a reliable result, it is important to follow the included instructions. There are several rules on how to get a more reliable result:

There is no need to try to determine the presence of pregnancy later than 5 minutes from the start of the test. Only before this does the test give the correct result. Even if a second line appears after 5 minutes, this will not be a reliable result.
The content of hCG in the blood is higher than in the urine; therefore, a blood test gives the correct result at an earlier date.
The test is more accurate when done in the morning, provided you did not go to the toilet during the night.
With unsystematic menstrual cycle The gestational age may be shorter than expected, so the test may give a false negative result.
The test should not be used in the stale part of the urine, otherwise it may give an incorrect result: the test must be performed immediately after urination.