Can an oversensitive pregnancy test be wrong. Are pregnancy tests wrong?

May show incorrect results. The entire set of pregnancy test errors is usually divided into two types - false positive and false negative results. False-positive results include the detection of pregnancy in a non-pregnant woman. And false negative results include, respectively, the failure to detect pregnancy in a woman who actually became pregnant.

False positive pregnancy test results may be due to the following causal factors:

• The use of drugs to stimulate ovulation containing human chorionic gonadotropin (for example, Profazi, Pregnil, Ovitrel, etc.);


• Various tumor formations of the uterus, ovaries, kidneys, lungs and intestines;


• Increased production of chorionic gonadotropin in brain structures - the pituitary gland, for example, with tumors or traumatic brain injuries;


• kidney disease;


• Childbirth, abortion or miscarriage less than 1 month ago.

Thus, false positive pregnancy test results can be associated with various diseases that require qualified treatment. Therefore, when a false positive result of a pregnancy test appears, it is recommended to undergo a comprehensive examination in order to find out the reasons for the increased level of chorionic gonadotropin.

False negative pregnancy test errors can be due to the following reasons:

• Too early analysis;


• Diluted urine;


• Incorrect analysis.

That is, a false negative result of a pregnancy test does not indicate any disease.

The most common false positive and false negative pregnancy test errors are due to the following causal factors:

1. Too little pregnancy. If a test with a sensitivity of 20 - 25 IU / l is used, then it will only be able to correctly diagnose the presence of pregnancy for a period of at least three weeks. Thus, this type of test can only be done 15 to 17 days after the last unprotected intercourse. If the test is done before the 15th day from the moment of the alleged conception, he will show a negative result, that is, he will be mistaken. Due to the fact that sexual contact, which resulted in pregnancy, could occur literally 1 to 2 days before the estimated date of the next menstruation, doctors and scientists recommend doing a test with a sensitivity of 25 IU / l no earlier than 2 weeks of delay. In this case, the test will fail. If a pregnancy test with a sensitivity of 10 IU / L is used, then it must be done 7 to 10 days after unprotected intercourse. However, if a woman became pregnant 2 days before the start of the next menstruation, then on the 2nd - 3rd day of the delay, the test will show a negative result, since 7 - 10 days have not yet passed from the moment of conception. That is, the test will fail. That is why doctors recommend doing a test with a sensitivity of 10 IU / L only after 7 days of delayed menstruation;

2. Unsatisfactory quality of urine. For a pregnancy test, morning urine should be used, since it is in it that the maximum concentration of human chorionic gonadotropin. During the day, a woman can drink a lot, as a result of which the urine is diluted, and the concentration of gonadotropin decreases. In such a situation, a pregnancy test will determine the concentration of human chorionic gonadotropin in dilute urine and may be mistaken by showing a negative result;

3. Incorrect use of a pregnancy test. The test should be done strictly according to the instructions, and the result should be evaluated after a specified period of time. If the test was performed incorrectly, the result may be erroneous;

4. Kidney disease. With kidney pathology, the level of chorionic gonadotropin in the urine during pregnancy may not increase. In this case, the test will show a negative result, even if everything is done correctly, that is, it will make a mistake;

5. pathology of pregnancy. The test may fail if the pregnancy is ectopic or there is a threat of miscarriage;

6. Weak attachment of the fetus to the wall of the uterus. In this case, there is pregnancy, but chorionic gonadotropin is not produced in sufficient quantities. That is, the result of the pregnancy test will be negative and, accordingly, erroneous.

Among the many ways to find out if pregnancy has come, tests are in great demand. They are very easy to use and inexpensive. But women are often puzzled by the problem - is it possible that the result of the test is not a pregnancy error? The answer is unequivocal - yes, the tests are wrong. But mostly erroneous results depend on the human factor - improper storage or non-compliance with the instructions for use.

Varieties and principle of operation

All tests have one principle of operation - the determination in the urine of the pregnancy hormone produced by the future placenta (chorion). The source of hCG (human chorionic gonadotropin) is the tissues of the fetal egg, which began its development in the uterus or fallopian tube (in the case of an ectopic pregnancy). Then gonadotropin enters the blood, then excreted by the kidneys.

Tests to determine pregnancy are of the following types.

Express tests

The usual, often the cheapest method for determining pregnancy. The strip is placed in any container with freshly collected urine. There are 2 zones on the strip of such a test. The manifestation of the control indicates the suitability of the product, the test - about the "interesting situation". The presence of even a very pale test line indicates pregnancy. Some ultra-sensitive tests can show a result as early as a week after the expected date of conception.

Cassette (tablet)

They work on the principle of instilling a single drop of urine into a small, special container window. You can put urine there with a syringe or pipette.

Inkjet

Very convenient, as they make it possible to perform a study without first collecting urine in a container, even while at work.

It is enough to substitute the test under a stream of urine. They usually have higher sensitivity than test strips.

Digital (electronic)

A modern system for determining pregnancy, where the screen can show both the presence of an “interesting position” and the period in weeks. This test is the most reliable and guarantees an accuracy of up to 99%.

This method is the most expensive, in comparison with all other tests.

False positive result

A pregnancy test may give a positive result, but there is no fact of pregnancy. In what cases can this be?

Most often, a false positive result is given by an incorrect interpretation of the test result.

The packaging of each test product has instructions. According to it, you need to evaluate the result of the study. A positive test strip result is rarely considered correct if its evaluation occurred later than 5-7 minutes from the start of testing. Sometimes on such tests there is a small blurry mark or a barely perceptible outline in the place of the test strip. Some women mistakenly take this as a positive result of the study. Sometimes self-hypnosis of the desired positive result plays a role in misinterpretation.

False positive test results are quite rare. It often happens that the opposite happens.

Often the following situation occurs: a woman is pregnant, but the test does not confirm this. The main reason for the erroneous result is too early diagnosis. Test manufacturers write on the packages that they can be used from the first day of the delay.

However, many tests cannot show a positive result not only on the first, but even on the seventh day after the start of the delay.

This is more common with simple low sensitivity test strips. This story rarely happens with high sensitivity test systems 10-15 Mme/ml. Most often, with a false negative outcome of the study, it is recommended to repeat the test after two to three days.

Other reasons for test failures:

1. The study was not conducted using morning urine. At an early stage of gestation, it is precisely that portion of the pregnant woman's urine that is collected in the morning that contains the maximum of chorionic gonadotropin.
2. A large amount of liquid drunk at night reduces the content of hCG in the test urine. The less a woman has consumed liquids, the more likely the correct outcome of the test.
3. Threat of abortion and miscarriage. The presence of a negative result can cause a serious problem of an incipient miscarriage or a stop in the development of the embryo.
4. Taking certain medications. A false-negative outcome of testing may be due to the intake of tranquilizers, diuretics and other drugs.
5. Pathology of the kidneys and thyroid gland. Some diseases of these organs can lead to hormonal imbalance. Failures in the work of the kidneys lead to a deterioration in the synthesis of substances. This, in turn, negatively affects the test result.

Common Causes of Errors

There are a number of points where the tests are wrong both in the presence and in the absence of an "interesting position". This may be due to an ectopic pregnancy.

Also, the causes of errors sometimes include the poor quality of products from unreliable manufacturers. Saving on reagents and materials with non-compliance with the rules of manufacturing techniques sometimes makes women pretty nervous because of the erroneous outcome of the study. This also includes non-compliance with storage conditions, impaired integrity of the package, delay of test products. In such cases, it is recommended to repeat the test.

Is it possible to make a pregnancy test error in the modern world? Couples planning to become parents often ask a similar question. Those who avoid pregnancy also have to be interested in the relevant topic. In this area, even 1-2 days play a huge role. For example, with a certain period of "interesting situation" abortion is done only for medical reasons. If pregnancy is diagnosed in a timely manner, such situations can be avoided.

Test types

The likelihood of a pregnancy test error often depends on several factors. Among them are:

• strip strips;
• tablet;
• jet;
• electronic.

All tests have the same principle of action. But can a pregnancy test be wrong? Reviews of such events are left by women quite often. And therefore it is worth noting that home diagnostics of pregnancy is not always accurate. The probability of errors is not high, but it takes place.

Test Accuracy

How often are pregnancy tests wrong? And why does it come out like that?

The thing is that the accuracy of modern pregnancy tests depends on several indicators. Namely from:

• sensitivity (most devices have a sensitivity of 25 mMe);
• its type;
• the time of the inspection;
• diagnostic techniques.

In general, modern devices for home pregnancy diagnostics are 95-98% accurate. Especially if you follow the technique of obtaining the result.

Most often, strip strips are mistaken. On the day of delay, its accuracy is about 90%. Tablet devices offer to determine pregnancy from the first day of the absence of menstruation with a probability of 92-95%, jet - 95%, digital - 99%.

However, no one is safe from a pregnancy test error. To reduce the likelihood of a false result to a minimum, it is recommended to understand the technique of conducting home express pregnancy diagnostics.

Instructions: how to do the test

There is a chance of a pregnancy test error, but it is not too high - from 1 to 10%. This is quite normal, because at first even doctors can take a fetal egg without a heartbeat for a tumor or other neoplasm.

Here are the techniques for properly conducting pregnancy tests at home:

1. Unpack the strip. Collect some morning urine in a sterile container. Before that, it is recommended to wait 2-3 seconds. Let the very first urine "merge" a little. This will help avoid mistakes. Next, you need to lower the strip strip to the control value for 5-10 seconds in the collected urine and put the test on a flat, dry surface. The result can be assessed in a maximum of 10 minutes.
2. The tablet pregnancy test is more accurate. It usually comes with everything you need for diagnostics. You need to collect urine in a container, and then draw it into a pipette. Drop on a specially designated area-window and wait. The indicator on the tablet will indicate pregnancy or its absence.
3. Inkjet tests eliminate the need to collect urine. This greatly simplifies the entire diagnosis. It is enough to substitute the device with the receiving end under the stream of urine for a few seconds, and then put it on a dry, clean and even surface.
4. Electronic tests are different. Most often they are used like inkjet or tablet. In some cases, the gestational age even appears on the screen of the device.

That's it: the error of a pregnancy test if these instructions are followed will be minimal. Especially if you do not diagnose before the delay of menstruation.

The main reasons for a false negative test

When is a pregnancy test wrong? This can happen under various circumstances. Moreover, the girl is able to face different diagnostic results on tests of various companies.

The most common false negatives occur when:

• incorrect diagnosis of pregnancy;
• the check was made too early;
• the test has expired;
• the diagnostic device was stored incorrectly;
• the girl used stale urine;
• the level of hCG is too low due to the individual characteristics of the organism;
• pathologies were revealed during pregnancy (threats of interruption, ectopic position);
• taking diuretics or hormonal drugs.

Of course, do not forget that manufacturers of pregnancy tests offer different quality of their devices. The Clearblue test is notable for its accuracy. Devices from this manufacturer are used more and more often. Evitest is also happy.

Practice shows that a pregnancy test error occurs with cheap diagnostic devices. "BiShur" or "NauKnow" more often than others give a false pregnancy result. It is recommended to always remember this, especially when choosing a pregnancy test manufacturer.

False positive rate

It is hard to believe, but the second strip on the device for diagnosing pregnancy can also appear due to an error. Pregnancy tests are wrong. It is a fact. And therefore, doctors recommend not to check for the success of conceiving a baby before the delay of menstruation.

A false positive result on pregnancy tests occurs if:

• the woman is being treated for infertility;
• the abolition of hormonal drugs occurred less than 10 days ago;
• the girl has tumors or inflammation;
• a woman has recently had a miscarriage;
• a recent abortion.

As practice shows, a pregnancy test error causes a lot of trouble. You have to either repeat the diagnosis or refine it.

Weak bar - how to interpret

Some girls have a "ghost" on the corresponding device during verification. This is the second, but pale and weakly expressed, barely noticeable strip. How to interpret such an indication?

Of course, ideally, it is recommended to repeat the diagnosis the next day. Another "ghost"? Then it is better for a woman to clarify the result or conduct another home check in a couple of days or contact a gynecologist who will be able to determine pregnancy with greater accuracy.

Most often, "ghost" is a positive result. It may appear when:

• low level of hCG;
• early diagnosis of pregnancy;
• pathology of pregnancy;
• ectopic pregnancy.

Such a phenomenon can also be considered a false positive. As a rule, the second faint strip is just a reagent. Clearblue and Evitest tests are distinguished by their quality and their reagents rarely show up as a "ghost". This cannot but rejoice.

Device marriage

Can an electronic pregnancy test be wrong? Yes, but this happens very rarely. To minimize the likelihood of errors, a woman is recommended to be treated before planning a baby, and then follow the previously proposed instructions.

When is a pregnancy test wrong? This can happen if a girl bought a defective device. No one is immune from such situations, therefore it is recommended to purchase several tests from different manufacturers for accurate diagnosis of an "interesting situation".

Important: Defective devices show both false negatives and false positives.

Clarification if necessary

How often are pregnancy tests wrong? Modern home pregnancy diagnostic devices offer an accuracy of determining successful conception with a probability of 90-99% on the first day of a missed period. A few days before this, the test can show an accurate result, but this is a huge rarity. Why? The level of hCG before the delay of critical days is at very low levels. That is why it is better not to rush into the diagnosis.

How to clarify the results of a pregnancy test? The girl can:

• repeat the study after a few days;
• donate blood for hCG;
• go to the gynecologist;
• make the pelvis.

All this helps to determine pregnancy with a greater probability than just a quick test made on time.

Important: on ultrasound, you can listen to the fetal heartbeat. This becomes possible around 5-6 weeks of pregnancy.

Is it possible that a pregnancy test is wrong? Unfortunately yes. If you do not choose a device for diagnosing an "interesting situation" and buy the cheapest one, you may encounter false readings.

Can a woman somehow minimize the chance of a pregnancy test error? Yes, but not 100%.

Here are some tips to help you avoid false results in home pregnancy diagnostics:

1. Carefully choose the manufacturer and type of pregnancy test.
2. Check the expiration date of the pregnancy test device.
3. Do not diagnose before the delay of menstruation.
4. Perform all manipulations with the test according to the instructions.
5. Do not drink a lot of water before the diagnosis and do not take diuretics.
6. Repeat the check a couple of times with some interval.
7. Do not use old urine for diagnosis.

All this really helps to cope with the task. Unfortunately, it is not always easy to diagnose pregnancy in the early stages. And so you have to use several methods at once to check the success of conception.

Any woman who suspects pregnancy usually goes to the pharmacy for a pregnancy test. Unfortunately, the results may not be correct. Can a pregnancy test be wrong?

A home pregnancy test works by measuring the urine levels of human chorionic gonadotropin (hCG), a hormone produced by the embryo and then by the placenta. When the hCG level reaches 5-10 mg (depending on the sensitivity of the test), two strips appear on the test. However, this result should be taken with caution.

A false result may be due to poor quality of the test or an expired expiration date. Expired tests or tests that have been stored in the wrong conditions can give unexpected results, so buy tests from trusted pharmacies and reputable manufacturers.

False positive pregnancy test

Can a positive pregnancy test be wrong? Maybe. Sometimes a positive pregnancy test does not mean no pregnancy. One such case is waiting too long for a result. It also happens that when impatiently looking for a second line, a thin strip is taken for it, in which a line will theoretically appear. Unfortunately, only a clear colored line can be considered as confirmation of pregnancy.

It also happens that a positive pregnancy test result is actually caused by factors other than pregnancy. For example, medications used for luteal phase problems. It can also result in blood or protein in the urine (with a urinary tract infection) or some forms of cancer (uterine, breast, ovarian).

If you are taking vasoconstrictor or hormonal drugs, diuretics or tranquilizers, this may distort the test results due to the “wrong” hormonal background.

False negative pregnancy test.

Sometimes the opposite happens. The woman believes that the pregnancy test is negative because she does not see two lines. This happens most often when the pregnancy test is performed too quickly and the hCG level has not yet reached the detection level. Another reason is an ectopic pregnancy, when the embryo is fixed in one of the fallopian tubes. Drugs such as promethazine, hypnotics and sedatives, diuretics, anticonvulsants and some contraceptives may also have an adverse effect.

Finally, recent US studies report that the effectiveness of pregnancy tests drops sharply after the seventh week of pregnancy, when another form of hCG appears in the urine and the actual measurement of the hormone is disrupted.

A false positive result can be obtained in case of ovarian dysfunction and a number of other diseases of the reproductive system.

When to take a pregnancy test so as not to be deceived

If you have already decided to take a pregnancy test, then there is probably a well-founded reason for this. Most often, it becomes a delay in menstruation, but also quite often we have other reasons. And it happens that a woman knows the result almost 100%, but still wants to confirm her guesses. And then it turns out that they are not confirmed.

Of course, we trust our own feelings and intuitions more. But getting an unexpected result brings doubt and anxiety. Can the test give an erroneous result? And when is a pregnancy test wrong? Now we'll find out.

Can a pregnancy test be wrong before a delay and in the first days of a delay

It is unlikely that there is at least one system, device or equipment in the world that is incapable of making a mistake. What can we say about the usual pharmacy test systems for pregnancy. Even ultrasound does not always show pregnancy or takes some other formation for a fetal egg.

Therefore, the answer is unequivocal: yes, a pregnancy test can be wrong. But something needs to be clarified here.

An erroneous result can be false positive (that is, show pregnancy when it really is not) and false negative (do not show pregnancy when it really is). The test is far from always “guilty”, especially if you test too early, even before your period. Moreover, sometimes it works correctly, that is, two stripes appear quite thoroughly, but for a different reason, not related to conception.

However, we will now consider all these causes and situations in detail.

The likelihood of a pregnancy test error

In practice, women quite often doubt the veracity of the results obtained. There is evidence that the percentage of such doubts reaches approximately 15-25. But in reality, errors occur much less frequently.

Manufacturers of test systems claim 95-99% accuracy. That is, false erroneous results range from 1% to 5%, and this is confirmed by practicing gynecologists.

Women often ask each other questions like which pregnancy test is the most accurate or which one can be wrong: Evitest, Frautest, Clearblue, L-test, Bee-Sure? But in fact, if all the testing rules are followed, even the cheapest test strip is able to show a real truthful result, while in certain cases even an error in an inkjet or electronic (tablet) test, which are considered the most accurate, is not excluded.

What determines whether a pregnancy test will show an erroneous result or a true one?

In what cases can a pregnancy test be wrong: reasons

In fact, many different factors can influence the result obtained during testing. In particular, you must always check the current expiration date, the integrity of the packaging and follow the instructions in the instructions. By dipping the strip into the urine with the wrong end, at the wrong depth, or holding it for less/more than the allotted time, you are unlikely to get true data.

If, after testing, you do not observe a single band, this means that either the test is not suitable for use (that is, defective), or you made mistakes during the study. In addition, other factors also affect the accuracy of the result.

It should be understood that a positive result occurs only if the level of human chorionic gonadotropin, the hCG hormone, rises in the woman's urine (the fetal egg formed after conception begins to secrete it). Any test (regardless of its type, manufacturer and price) contains a reagent that manifests itself only by reacting with the hCG hormone, and this is possible only when the amount of this hormone in the woman's urine reaches a certain level (in practice, this level is reached 7-10 days after conception). If there is not enough hCG in the urine to “be noticed” by the test, then we will get a negative result.

Negative pregnancy test error

As practice shows, false negative results occur more often. The reason for such an error (in addition to those already described above) may be hidden in the following:

1. The test was taken too early, even before the delay of menstruation. Despite the fact that many supersensitive tests are able to show pregnancy a few days before menstruation, to obtain reliable data, doctors recommend testing no earlier than 2-3 days after the delay. And even in this case, it is impossible to trust the result obtained by 100% - it is recommended to repeat the test at least one more time, after 2-3 days.
2. Late ovulation in the previous cycle. In this case, conception will take place shortly before the expected menstruation, and the concentration of hCG simply will not have time to rise to the required level.
3. The urine was too diluted. The more concentrated the urine, the higher the chance of getting a true result. For this reason, testing is recommended in the morning with the first portion of urine. Moreover, on the eve it is undesirable to drink a lot, use diuretics, foods or drinks.
4. Pathological pregnancy - frozen or ectopic. In this case, hCG is either no longer produced (due to the freezing of the fetal egg), or an insufficient amount of it enters the urine (due to the attachment of the embryo not in the uterus).
5. Kidney disorders that prevent the normal release of urine with hCG.

Positive pregnancy test error

False positive results are less common, but it often happens that a positive test turns out to be true, however, for some reason, the pregnancy is terminated at the very beginning (often women do not even know that they were pregnant), and retesting may already show a negative result . In this case, it cannot be said that the test was erroneous. However, there are very serious reasons why we can get a false positive result:

1. Formation of hormone-producing tumors. There are tumors that produce the same hCG, which can lead a woman astray.
2. Hormonal imbalance. If the ratio of hormones in a woman's body is disturbed, then this leads to various disorders in her health and the functioning of the reproductive system, in particular, the menstrual cycle may go astray (delays occur). Therefore, the answer to the question whether a pregnancy test can be wrong with a hormonal failure is definitely affirmative. But with thrush, the test results are not distorted, as some girls think.
3. Recent abortion or miscarriage. If a woman has lost or terminated a pregnancy, and soon re-tests, it may turn out to be positive due to the fact that fetal membranes containing human chorionic gonadotropin remained in her body.
4. Reception of hormonal preparations containing hCG. It can be, for example, drugs to stimulate ovulation, if a woman is being treated for infertility. In this case, the level of hCG in the woman's urine will still remain quite high for about 2 weeks after stopping treatment.

It should be noted that a pale, weak second strip is regarded as a positive result, but it requires a mandatory repetition of testing after a few days in order to exclude the possibility of developing a pathological pregnancy, in which hCG is produced by the fetal egg in insufficient quantities.

The IVF method itself does not affect the test results. However, you need to know that it is possible to conduct a test with this method of conception only 10-15 days after embryo transfer.

How to know if pregnancy tests are wrong

We cannot know for sure when a test is wrong and when it is true. That is why doctors always emphasize that any test result must be rechecked 1-2 more times. If something worries you (for example, 2-3 tests showed a positive result, but there are no periods; or signs of pregnancy persist for a long period of time, but the tests are negative), then you should definitely visit a doctor. You should also undergo an examination by a gynecologist in any case when the test shows pregnancy: he will refer you to an ultrasound scan, because only by its results can final conclusions be drawn. And even then - not always. Keep in mind that in some cases, ultrasound may not see the fetal egg in the uterus for quite some time, even when it develops quite safely.

Especially for - Larisa Nezabudkina