A pregnancy test is a convenient invention that allows a woman to find out about her situation long before visiting a doctor. The result obtained at home will help to know about the presence of pregnancy, provided that the test is used correctly.
Express diagnostics has a number of features that also depend on the type of device.
The principle of operation of any test for determining the conception that has occurred is similar - this is a reaction to the content of a special hormone in the urine of a woman - chorionic gonadotropin. It is abbreviated as hCG, and the body begins to synthesize it after the fertilized egg attaches to the uterine lining for further development.
That is, a positive pregnancy test can be seen only after the conception has occurred.
An important question for many women is when to take a pregnancy test. It should be borne in mind here that in the first days after conception, the amount of hCG in the urine is minimal, but these figures increase every day. To get an accurate result as early as possible, it is better to donate blood from a vein in the laboratory in the early stages of the intended pregnancy. So the result can be obtained earlier by about 5 days before the test shows two strips. And even a barely visible second strip in the first days after conception makes women doubt.
Instruction
Instructions for a pregnancy test - something that must be read without fail. After all, the accuracy of the result depends on the correct use of the device. Much depends on the type of rapid test, of which there are several.
Strip test (or test strip)
Inexpensive and most common device in the form of a paper strip with a reagent applied to it. How to use it, questions usually do not arise. The morning urine must be collected in a clean container, lower the strip for about 10-15 seconds, and put the test on a dry surface.
The result will appear in a few minutes. Here, too, everything is simple: one stripe - there was no conception, two stripes - conception occurred.
Tablet
The principle of the device is similar to the previous one, only the paper strip is in a plastic case. When is the best time to take this type of pregnancy test? Also in the morning. Only here it is necessary, using the attached pipette, to drop morning urine onto a special window in the device. The result is also evaluated by the number of strips.
Jet
Probably the most convenient device since it does not require urine collection. To obtain the test, you need to substitute it under the stream of urine and not necessarily in the morning, since tests of this type are more sensitive.
The result is again the same stripes - two or one.
Electronic
If an electronic pregnancy test is chosen, the price will be significantly higher than a simple test strip. But the result should be expected as accurate as possible.
As part of the kit, there is a sample receiver, which must either be held under a stream of urine, or lowered into a container with the collected liquid. The difference with other types of devices is when it shows the result. The result should be evaluated after 3 minutes. The result is "+" or "-", which respectively means the presence or absence of pregnancy.
When to do?
It is best to take urine in the morning for testing. The reason is that it has the highest concentration of containing substances, including.
But jet-type tests can be done at any time of the day due to their higher sensitivity. They have an indication - 10 mIU / ml.
Until the delay
The result of the test depends on the amount of hCG in the woman's urine. The amount of the hormone increases every day. Will the test show an accurate result before the delay? Here again it all depends on the sensitivity of the device. Some of them, and, as a rule, the most expensive ones, are able to determine the presence of pregnancy already 7 days after the expected conception, that is, before.
But already a week after the delay, any test can show a probable conception, since the level of hCG is already quite high.
Can the result be wrong?
Whether a pregnancy test can be wrong depends on the device itself. Manufacturers, as a rule, indicate on the packaging about the accuracy of up to 95 - 99%. So there is 1 - 5% for the wrong result.
Reasons for a false negative result may include:
- testing was carried out very early, so the content of hCG in the urine of a woman is not enough to determine;
- incorrect testing (read the instructions);
- an expired device was used (this must be checked upon purchase);
- a large amount of liquid drunk on the eve of testing (urine becomes less concentrated, which means the amount of hCG decreases).
If the test is false positive, the reasons may be as follows:
- a woman taking medications in the treatment of infertility (these are usually injections that contain the hCG hormone);
- little time has passed after a miscarriage or premature birth (the remains of the embryo may remain in the uterus);
- the presence of malignant neoplasms.
It is worth mentioning that very weak second strip. If it is, then there is pregnancy, only the content of hCG in the urine is still too low.
If there is any doubt about the result of testing, it is worth repeating it again after three days. During this time, the amount of hCG will increase, and the second band will appear brighter.
With an ectopic pregnancy
Test at will have . After all, almost the same thing happens in the body as during normal gestation, with the exception of the place of attachment of the embryo. The egg is fertilized, the embryo develops, and therefore hCG is produced in the body.
It is important to recognize the ectopic development of the fetus in time to avoid dangerous consequences. Its arbitrary interruption usually occurs at 7-8 weeks, which is accompanied by severe pain and bleeding.
You can suspect an ectopic pregnancy if you have symptoms such as nagging abdominal pain and spotting with a positive test. If there are such signs, you should immediately consult a doctor.
To confirm an ectopic pregnancy, an ultrasound will be performed, and a blood test for hCG will be taken. Here, the dynamics of the hormone content is taken into account, since with an ectopic development of the fetus, the content of hCG in the blood is below normal.
What will the test show at? If during the first test there were two clear bands, and after some time the device shows a negative result, there will be a suspicion of fetal fading. Such a diagnosis is confirmed only by the doctor after the examination.
What to do if a woman sees a positive pregnancy test depends only on her. Someone will be upset, but for someone such a result will be the most desired. Expectant mothers can only wish peace, fewer nerves, adhere to a healthy lifestyle and eat right. And, of course, it is necessary to make a visit to the doctor as soon as possible for examination and receiving important recommendations.
On the video about the correct application
Pregnancy tests are an affordable and easy way to diagnose conception at home. Nowadays, you can buy a rapid test at any pharmacy or supermarket. But the result of the study is not always accurate: sometimes the doctor does not confirm the presence of pregnancy, or, conversely, it is, and the test shows a negative result. Are pregnancy tests wrong and how to avoid this inaccuracy?
It is unlikely that in our world there is at least one error-free device, system or equipment - all of them, due to certain factors, have a percentage of errors and can be wrong. This also applies to express tests that are used by women on their own. Pregnancy test errors are possible, and this will be discussed in our article.
After conception, the fertilized egg implants in the wall of the uterus. From this moment on, the hormonal background changes in the woman's body. The embryo begins the production of chorionic gonadotropin () - the hormone of pregnancy. A few days later, the presence of this hormone is found in the blood, and a little later in the urine. The purpose of a pregnancy test is to detect hCG in a woman's urine.
A certain part of the device is coated with a substance that, when in contact with urine, reacts to the presence of human chorionic gonadotropin. If the hormone is present in the proper amount, a reaction occurs, and a coloring component appears, indicating the presence of pregnancy. In this case, the woman sees an additional (second) line on the test strip or in the result window.
If there is no hCG in the urine or its concentration is too weak, the pigment will not appear. The test will show a negative result or one control line.
Why do mistakes happen?
Sometimes even high-quality pregnancy tests, carried out according to the instructions, give an erroneous result. Why is this happening? It turns out that there are many factors that affect the correctness of the answer. According to experts, the results of the diagnosis can be false positive and false negative.
Reasons for a false negative test:
- Diagnosis was made too early, long before the delay in menstruation. Even supersensitive test systems are able to give a reliable result no earlier than 2-4 days before the expected menstruation.
- in this . In this case, the possible conception will occur somewhat later than expected. Even if the test is done in the first days of a missed period, the hCG level will still be insufficient for a positive result.
- The use of large amounts of water or diuretics on the eve of the diagnosis. Weak urine concentration reduces the veracity of testing.
- Pathological pregnancy:,. In this case, an insufficient amount of hCG will enter the urine, and the test may show a dubious and even negative result.
- Kidney disease that prevents the growth of the normal concentration of hCG in the urine.
Reasons for a false positive test:
- The presence of hormone-producing neoplasms in the body. There are tumors that synthesize hCG. They can be localized in the kidneys, uterus, stomach, etc.
- Treatment with hormonal preparations containing hCG. For example, conservative infertility therapy with Pregnil, etc.
- Transferred in the recent past artificial or.
How to understand if the test is wrong?
It is impossible to say for sure that the test was wrong or showed the truth. Therefore, experts insist that any study should be rechecked after 48 hours. If two or three tests in a row show that there is no pregnancy, but you should consult a doctor.
It is also necessary to visit a gynecologist in case of a positive diagnostic result. In both cases, the specialist conducts an ultrasound, the results of which are the final conclusions.
How to avoid mistakes
Even the most sensitive test can fail. First of all, expired products can fail. Therefore, at the time of purchase, it is important to pay attention to the expiration date and storage conditions of the express test. It is better to buy goods in a pharmacy.
When choosing a test, pay attention to the manufacturer. Popular large manufacturers are unlikely to release untested defective devices.
Cheap tests are made from inexpensive and low-quality materials. Therefore, the result of the study may be questionable. The absorbent part of a cheap rapid test can get wet and shift towards the coloring pigment, indicating the presence of pregnancy. As a result, a woman will take such a result for pregnancy.
Pregnancy test errors can also occur if the device is used incorrectly. For example, if this is due to a violation of the time spent by the express test indicator in the urine. If the time of immersion of the indicator into the biological fluid is not observed, it simply will not have time to soak in it, and the result of the study will be erroneous. An error can also occur if the indicator is overexposed in the urine or immersed above the set limit.
To avoid mistakes, the express test must be used according to the instructions. Failure to follow the recommendations for use may distort the result of the diagnosis.
What tests are considered the most accurate
There are three main groups of tests: test strips, tablets, and inkjet devices.
Test strips are the most popular. The principle of their operation is simple: the indicator is lowered into a small amount of urine, and after 5 minutes you can evaluate the result. Staining of the second strip means that the test is positive, the absence of pigment staining indicates the absence of pregnancy.
Sometimes the second strip stains barely noticeable, and a similar result is considered weakly positive. In this case, it is recommended to repeat the diagnosis after 48 hours.
Test strips are less reliable. The inaccuracy can be associated with low-quality materials from which the system is made, and a violation of the instructions - such a test is easily overexposed or underexposed in the collected urine.
Test systems in the form of a tablet are more expensive, the quality of their results is higher, but the principle of operation is the same as with test strips. The device includes two windows: urine is instilled into one of them using a pipette, and the result is read in the other.
Inkjet tests are considered the most accurate. Some inkjet test systems determine the presence of pregnancy 4-5 days before the expected delay. In addition, they are convenient to use - you do not need to collect urine, and you can carry out diagnostics at any time of the day. Errors when using inkjet tests are practically excluded.
In any case, experts recommend rechecking the test result 2-3 days after the study. It is advisable to use a test system from another manufacturer for this purpose. Whether pregnancy tests can be wrong is an ambiguous question. If the test is chosen correctly, its expiration date has not expired, and the diagnostics were carried out according to the instructions at the right time, the probability of error is minimal.
Useful video about using a pregnancy test
An express test for determining pregnancy is considered the most accurate way to determine conception. However, even such ultra-sensitive devices can fail.
A pregnancy test can be false positive for a variety of reasons. Before you panic, you need to find out why the error occurred, as sometimes it is associated with serious health problems.
What could be the reason for the erroneous result and how to find out the reliability of the test? Let's explore this issue in more detail in this article.
What is a false positive pregnancy test
If a girl tested before her period, then the result may be erroneous. This is due to the fact that in the early stages of fetal development, the amount of synthesized chorion hormone did not reach the desired concentration. Because of this, the express strip does not show that fertilization has occurred.
The hCG hormone is sometimes synthesized in the female body even without fertilization. If a woman has thromboplastic neoplasms in her body, then a pregnancy test can show a positive result. This is due to the fact that such cells synthesize such a hormone as the placenta, therefore, when conducting home diagnostics, the test will show a second strip.
A false-positive result is also considered weak or blurry stripes. If the first test gave such a result, it is best to repeat the diagnosis in a couple of days or immediately contact the antenatal clinic.
The home rapid pregnancy test is a convenient and easy-to-use device that can quickly determine if a girl is pregnant. Devices from popular manufacturers have high sensitivity and most often show the correct result in 95% of cases.
However, there are erroneous results associated with health conditions or other anomalies. Why are these reliable devices wrong?
When a Test Shows a False Positive - An Overview of Possible Causes
Several factors influence the performance of the devices.
Let's study them.
Human factor
Incorrect answers during diagnostics are obtained for the following reasons:
- During the study, the instructions for use of the device were not followed, or the container for the biological fluid was dirty.
- The woman violated the conditions for storing the test or accidentally knocked over a container with liquid on it.
- Self-hypnosis. A girl can convince herself that she is pregnant and see the ghostly two stripes.
- The woman conducted the study during ovulation.
- If the girl is still breastfeeding, then the test will show a positive result, since little time has passed since the previous birth.
- The psychological state of a person. If a girl is very worried or, on the contrary, has experienced a lot of positive emotions, a strong surge of hormones occurs in the body, which will lead to false results.
Health related reasons
Quite often, when a second strip appears, a woman thinks that the test was simply wrong or that she did it wrong. However, this is not always the case. Not always a positive answer is displayed for banal reasons. Sometimes the reason for this is serious health problems.
Possible causes of erroneous analysis:
- pelvic disease;
- endometritis;
- ectopic pregnancy;
- hepatitis;
- syphilis;
- ovarian cyst;
- corpus luteum cyst;
- hormonal disorders;
- the onset of early menopause;
- development of cancer cells;
- uterine fibroids;
- miscarriage.
You can’t joke with health, because if treatment is not started on time, this will lead to serious consequences. If a girl has signs of ill health (pain in the lower abdomen, dizziness, nausea, fever, spotting), and the test gives two strips, then you should immediately contact a gynecologist and undergo a full medical diagnosis.
If any abnormalities are detected, immediate treatment should be started. Do not be afraid to go to the doctor, an unscheduled examination by a gynecologist will help you find out if the woman is healthy and if the long-awaited fertilization has occurred.
Other reasons
An erroneous positive test can also occur if the girl took drugs containing hCG or drank contraceptives before the diagnosis. In this case, so that there are no errors in the study, it must be carried out 14-15 days after the end of the course.
And also before using the device, you need to carefully look at the expiration date. If it is overdue, then the probability of a true result is very small. This is due to the fact that after the expiration date, the reagent in the test dries out and loses its properties. Therefore, the test results will be inaccurate. It is best to go to the pharmacy and buy another pregnancy test.
How to deal with a false positive test result
Modern testers have an increased sensitivity of 90–95%. The electronic test from the Clearblue company has a hypersensitivity of 99%. Therefore, carrying out diagnostics in compliance with all the rules, the correctness of the results will be in 99% of cases.
However, there are times when the express strip shows two strips, but there is no pregnancy. You don't need to panic right away. It is impossible to judge the accuracy of the results only on one test.
First of all, you need to re-examine after 2 days. If it also shows two stripes, you must visit the gynecologist's office and undergo a medical examination.
Do not forget about the color of the second strip. If, after testing, the second strip appears pale pink or blue, then pregnancy is most likely not. This phenomenon may be due to non-compliance with the instructions or a malfunction of the tester.
And there are many other factors to consider when conducting a home study. In any case, if two lines appear on the express test, you need to contact the antenatal clinic and make sure that your testing is correct.
How to act so as not to make a mistake
Any device is mistaken, even electronic. To avoid mistakes, it is necessary to carefully study the expiration date of the device, storage method and instructions for use. According to experts, it is best to buy devices in a pharmacy.
When choosing a device, you need to pay attention to the manufacturer. The most popular and sought-after devices are often the most accurate. The company is responsible for quality assurance, so defective batches are rare.
Pay attention to the price of the device. If its cost is minimal, then it may be made of low-quality and inexpensive materials, which negatively affects accuracy. Follow the instructions and recommendations, then the probability of error will be minimal.
How to avoid mistakes in determining pregnancy will tell the reproductologist.
Conclusion
Pregnancy testers are universal devices that help detect conception without going to the doctor. However, there are times when the diagnosis shows false results. This happens very rarely, and there are reasons for that.
When conducting diagnostics, it is necessary to take into account the human factor and the state of health of the girl. Perhaps it is because of this that two bars are displayed on the display. To avoid a false positive answer, systematically undergo examinations with specialists and regularly visit a gynecologist.
Pregnancy tests are an easy and affordable way to determine conception. Many women often resort to their help. However, sometimes it happens that the test result turns out to be incorrect: the presence of pregnancy is not confirmed by the doctor, or, conversely, the test indicates the absence of an existing conception. Are pregnancy tests wrong? Consider how such devices work and why they sometimes show incorrect results.
How pregnancy tests work
All types of pregnancy tests work on the same principle - they determine the concentration of human chorionic gonadotropin (hCG) in the urine. This hormone begins to be produced by the embryo immediately after it joins the wall of the woman's uterus. It is produced by the chorion of the embryo, which is the rudiment of the future placenta. Usually, the production of hCG begins 7-8 days after the fertilization of the egg, that is, after the moment of conception.
Consider test strips as an example. The part of the strip (absorbent) that is immersed in the urine sample contains a special substance that is chemically bound to the dye. If the required concentration of the hCG hormone is present in the urine, a reaction occurs, as a result of which the dye is released. At the same time, a colored line appears on the test strip (most often blue or crimson). Its brightness depends on the level of hCG concentration in the urine. If this hormone is absent, the reaction does not occur and the test strip does not stain.
The probability of a pregnancy test error depends on its type and is 1-5%. Test strips are quite cheap, but they are also most often mistaken. Tablet tests are more expensive, and their results can be more trusted. The tablets have two windows, into one of which a few drops of urine are dropped with a pipette, and the result appears in the second. The most accurate are called inkjet tests. According to reviews, they can be used to determine the presence of pregnancy even a few days before the expected start of menstruation. Inkjet tests are substituted under the stream of urine as indicated in the instructions, and after a few minutes the result of the analysis appears.
An incorrect result can be seen on any of the tests. So are pregnancy tests wrong?
Why Do Pregnancy Test Errors Occur?
There are many reasons for erroneous test results. Let's consider the main ones.
When buying an express test, you need to carefully look at the indicated expiration date. An expired product is more likely to give the wrong answer. In addition, it is important to pay attention to the storage conditions of the test, often improper storage makes it unusable. On the packaging of most express tests, it is noted that if not a single strip appears during the analysis, then the test is defective. You should not buy very cheap products, the quality of the control strip, which is very low. Thus, when wet, it can blur in the direction of the "pregnant" strip, which is often taken as a positive result. And, of course, you must strictly follow the instructions for the analysis. An incorrectly performed test can give both a false negative and a false positive result.
But it happens that both the test is qualitative and the analysis was carried out according to the instructions, and the answer received is incorrect. Are pregnancy tests wrong for other reasons? It turns out that there are many factors that affect the correctness of the answer. Experts distinguish between false positive (the test determines a pregnancy that is not present) and false negative (the test indicates the absence of pregnancy, if any) results.
A false positive result is due to the fact that the woman's body has the hCG hormone, the production of which is not associated with pregnancy. The causes of this error are the following conditions and diseases:
- recent abortion, miscarriage, or ectopic pregnancy;
- A short period after previous births;
- The presence of trophoblastic tumors that produce the hormone hCG (chorioneptelioma, hydatidiform mole);
- Hormonal failure of the body, impaired functioning of the ovaries;
- Taking medications that contain hCG.
False negatives are much more common than false positives. Usually its cause is too early analysis. The maximum possible sensitivity of rapid tests is about 20-25 mIU / ml. The level of hCG in the blood reaches this value at 7-10 days after conception, and in the urine even later. Therefore, it is desirable to do the analysis no earlier than 10 days after fertilization. Test manufacturers advise testing no earlier than the first day of a missed period. In this case, the likelihood of a pregnancy test error is significantly reduced.
In addition, the following conditions become the reasons for receiving an incorrect test response:
- Drinking large amounts of liquid immediately before the test;
- Taking diuretics;
- Diseases of the cardiovascular system or kidneys that prevent the release of the hCG hormone at the right concentration;
- Risk of miscarriage;
- Frozen or ectopic pregnancy.
How to check if pregnancy tests are wrong
Experts advise: to check if the pregnancy test is wrong, you should repeat the analysis after two to three days. It is best to purchase a test from another manufacturer. If a positive answer is confirmed, it is necessary to contact a gynecologist. If, in the absence of menstruation, the test again shows that there is no pregnancy, you can analyze it a third time after 3-4 days. Having received a negative answer, you need to be examined by a doctor in order to establish the exact cause of this condition and, if necessary, start treatment in a timely manner.
Modern express tests are one of the most reliable systems for diagnosing early pregnancy. However, as statistics show, about 25% of women are uncertain about the reliability of the results. In fact, pregnancy tests can be wrong, but this happens infrequently and only under certain conditions.
All pregnancy tests, regardless of their price and method of application, are based on a single principle of work. They react to the presence of hCG (human chorionic gonadotropin) in the urine. Normally, this hormone is produced in the body in very small quantities, but after the fertilization of the egg has occurred, and the embryo has attached to the wall of the uterus, the level of hCG rises. This happens 7-10 days after conception. Therefore, most tests allow you to diagnose pregnancy already on the first day of a missed period, and sometimes even earlier.
A special substance is applied to the test, which, reacting with the hCG hormone from urine, turns bright in color. If the test is equipped with an electronic display, then the result of the study appears on it in the form of the words "pregnant", "not pregnant" or in the form of signs "+", "-".
Why can a negative pregnancy test result be false?
A false negative test result means that the device shows the absence of pregnancy, but in fact it is. This often happens when the concentration of human chorionic gonadotropin in the urine is too low for a reaction to occur.
There may be several reasons for this:
Conception happened shortly before the onset of menstruation, so chorionic gonadotropin has not yet accumulated in the body.
The woman took the test too early. Some systems allow you to diagnose pregnancy 4-5 days before the onset of menstruation. However, in this case, even the manufacturers themselves warn of the possibility of obtaining a false negative result.
The woman has an irregular menstrual cycle, which caused an error in the calculations. Again, there is pregnancy, but the test will show its absence, since there is still little hCG in the urine.
It is possible that the test gives a false negative result due to the existing threat of miscarriage or ectopic pregnancy. In this case, the hCG level will be lower, and the device will not be able to catch it. However, testing at a later date (7-14 days after a missed period) will detect an existing pregnancy, even if it is ectopic.
Sometimes a test gives a false negative result when using highly diluted urine for research. This happens while taking diuretics or other diuretics, as well as when a woman drank a lot of liquid during the day. This is especially true in the case when the study is carried out in the early stages. Therefore, all doctors give an unambiguous recommendation: to perform testing in the morning, immediately after waking up.
Another reason for getting a false negative pregnancy test result is serious kidney pathologies that are accompanied by kidney failure. Against the background of such diseases, the normal excretion of urine with hCG is simply impossible.
Why can a positive pregnancy test result be false?
Obtaining a false positive result is also possible, but the reasons will be somewhat different, among them:
A woman takes medications that contain human chorionic gonadotropin. These drugs include the drugs "Pregnil", "Ovitrel" and "Profazi". They are prescribed to women in the treatment of infertility. As a rule, even after the end of the therapeutic course, the level of hCG remains high for another 14 days. Therefore, a pregnancy test should not be performed within the indicated time frame.
The level of hCG in a woman's body can remain high after a miscarriage, a remote ectopic pregnancy, or an abortion. On average, the hormone content returns to normal within 4 to 30 days.
The test can be positive when a woman has cancer, including a tumor of the ovaries, kidneys, intestines, uterus, and lungs. Even with a pituitary tumor, a pregnancy test can give a false positive result, which is a consequence of a violation of hormone production.