The reliability of modern home pregnancy tests is quite high, and when carried out correctly reaches an average of 97%. A high-quality test allows you to determine pregnancy from the first day of your missed period. However, in some cases the result may not be true.
A false positive test result indicates the presence of pregnancy in its absence. That is, without being pregnant, a woman receives two test strips on her body. Why does this happen?
The reasons can be very different. And to understand why the test can deceive, let us briefly describe the principle of its operation.
A special reagent is applied to the test strip, which reacts with it, binding to it and turning red-pink. The dough sheet has two zones: control and test zone. The first is designed to confirm that the test is suitable for use (that is, it works properly); it simply reacts to urine. The second appears only if it is present in the urine. sufficient quantity HCG. The most sensitive pregnancy tests can detect it at a level of 25 mIU/ml. In most cases, the hormone chorionic gonadotropin increases to such indicators by the first day of the delay.
That is, in fact, a pregnancy test does not determine the pregnancy itself, but the increased level of hCG in a person’s urine. Normally, it increases only in women and only after the fertilized egg has been fixed in the uterus: the developing one (or rather the chorion) begins to produce this same human chorionic gonadotropin, which rapidly increases in the first weeks of pregnancy, doubling every two days and reaching its peak at 8-11 week. But the increase in hCG in the body (and in particular in the urine) of a person can be caused not only by pregnancy, and in principle, even men can use the test to determine its level, which can become an early diagnosis of the development of a tumor in the body.
This is because various types of formations are also capable of producing human chorionic gonadotropin: cysts, tumors. Therefore, in the absence of pregnancy, an increased level of this hormone may indicate the course of a pathological process in the body.
HCG in the urine may remain at high levels for some time after an abortion or miscarriage. If a woman has recently had it removed, then traces of hCG may also still remain.
In addition, some hormonal drugs can also increase gonadotropin levels, affecting test results.
In addition to a truly elevated hCG level in the absence of pregnancy, false-positive results may be the result of using a low-quality test or incorrectly reading the information. On some test strips, after the liquid dries, a blurry mark forms in place of the second strip, which can be mistakenly interpreted as a positive result. Therefore, a warning is always written that a result assessed no later than 5-7 minutes after immersing the test strip in urine is considered reliable. Please note that the presence of a second strip, identical in color, clarity and width to the control one, should be taken as a positive result.
So, the reasons for a false positive pregnancy test may be as follows:
- the presence of neoplasms in the body (chorion uterine epithelioma, hydatidiform mole);
- recent abortion, miscarriage or removal ectopic pregnancy;
- taking hCG-containing medications;
- low quality test;
- violation of test storage conditions;
- incorrect assessment of test results.
It should be said that false positive test results are relatively rare. Much more often, women receive false negative results when, even if they are pregnant, the test does not show it. In the vast majority of cases, this occurs due to home testing being carried out too early: the level of hCG in the urine is still too low for the reagent to “detect” it.
Especially for- Elena Kichak
For many women, the days before the start of menstruation are the most exciting. Therefore, even before the expected delay, they go to the pharmacy for a pregnancy test. This is the most effective way to determine " interesting situation"at home. However, such a diagnosis has some nuances. If the second line on the test is pale, the woman is at a loss: does this indicate pregnancy or not?
Let's figure out why this phenomenon occurs and how to respond to it.
Pharmacies sell all kinds of tests to determine pregnancy at home. They differ in the way the research is conducted. To use each of them, you need to study the features of their application.
Pregnancy tests include:
- Test strips. They are the cheapest means for determining pregnancy. To use them, you need to take a container into which a portion of urine is collected. After opening the package, the test is lowered into the container to the drawn border for no more than 5 seconds. After this, the test must be placed on a horizontal surface. You can evaluate the result after 5 minutes.
- Tablet tests. The principle of their operation is similar to the operation of a test strip. Only in this case, the test is not lowered into the container, but a drop of urine is applied to its surface using a special pipette. After the substance is distributed over the surface, the result is shown in the second window of the tablet.
- Inkjet tests. During this process, the strip is placed under the stream for a few seconds. After distributing the substance, the result is reflected in a special window.
- Electronic tests. They are the most expensive and reliable means of determining pregnancy. Electronic tests work on the jet principle. The main difference is the speed at which the results appear. Some types of tests even determine the estimated gestational age.
All tests are designed to detect pregnancy hormones in a woman’s urine. A special reagent is applied to the surface of the test, which is colored when a sufficient concentration of the hormone is reached in the body.
The level of hCG depends on the duration of pregnancy, increasing after fertilization. Every two days, hCG levels double. The hormone enters a woman’s body as a result of its production in the chorion membrane of the embryo. The first “doses” can be detected within a week after fertilization.
If the hormone is present in a woman’s body, instead of the standard one stripe, a second colored line appears.
In this case, several factors may influence the reliability of the result:
- dough storage and transportation conditions;
- best before date;
- research methodology;
- the presence of diseases in the female body.
In order to get a reliable result and not see a missing or second pale line on the test, it is worth finding out some of the reasons for the ambiguous reaction.
Pale line on the test in the absence of pregnancy
Sometimes a woman may see a pale line on the test. In this situation, there may be several options for the development of events. An important condition for assessing the result is the correctness of the testing procedure.
Test manufacturers provide detailed instructions to the product. It indicates how long the test strip should be immersed in the container, how long the test should be kept under stream of urine, and also after what time the result should be assessed.
Sometimes, even with proper use, a woman may find ambiguous results. This may result from uneven saturation of the surface of the dough with urine. Distribution most often occurs with errors on test strips. In this case, it is necessary to repeat the procedure using a tablet test.
The second common reason for a questionable result is early use of the test. Manufacturers recommend carrying out the diagnostic procedure no earlier than on the first day after the onset of a missed period.
Some tests indicate that they can be carried out even before the first day of the delay. Typically these tests have increased sensitivity. However, they can also give or false negative results. In this case, the second stripe may not appear at all or have weak, blurry outlines. Therefore, it is necessary to conduct a test when a delay occurs.
Manufacturers note that the second strip should be the same as the control strip: smooth, bright, and have clear edges. It should match the first strip in length and width. Only in this case the test is positive.
However, we can talk about pregnancy after a laboratory test to determine the hCG hormone in the blood. It is carried out at intervals of 2-3 days to assess the growth of indicators.
A pale second line on the test may appear after the allotted time limit for assessing the result. Sometimes women check the drawing on a test half an hour after the test. In this case, this result cannot be considered as positive: this may result in the appearance of residual reagents.
Sometimes this result can be obtained from a test performed after infertility therapy. During treatment, the woman takes medications that contain a small dose of the hCG hormone (Pregnili, Profasi). In this case, it may not be excreted from the body for some time.
A positive test with a pale second line may indicate the presence of certain diseases in a woman’s body. Often cells similar to a hormone produced by the chorion ovum, are formed in the presence of cysts. After examination, doctors can diagnose uterine chorionepithelioma and hydatidiform moles.
When is pregnancy possible if the line on the test is barely visible?
A second pale stripe may appear immediately during the test. In this case, pregnancy may be suspected. However, an accurate assessment can only be made after conducting a survey in medical institution to avoid disappointment in case of a false positive result.
A second pale line on the test may indicate low levels of the hCG hormone in a woman’s urine. This result can occur for several reasons:
- If the pregnancy is very short and there is no delay yet, then the strip may have a pale color.
- When using detoxifying agents excess liquid from the body (diuretics) dilute the urine. Also, low concentrations of the hormone can occur due to the consumption of foods that affect urinary function and increased kidney function.
- A weak second line may indicate abnormalities in the development of pregnancy.
- In the case of a frozen pregnancy, the test may show a weak second line.
- With an ectopic pregnancy, the test reaction may be ambiguous.
- If the test is performed during the period after an abortion procedure (abortion, miscarriage, curettage), the test may be positive. In this case, the presence of the hCG hormone is due to its incomplete elimination after a recent pregnancy.
What should I do if the test shows a pale second line?
An ambiguous result cannot be reliable for determining the presence of pregnancy. Therefore, repeated testing is necessary. You can use a different brand of test, or purchase it at another pharmacy.
However, doctors recommend conducting an examination using laboratory methods. The most effective test is to determine the hormone hCG in the blood serum. He surrenders on an empty stomach in the morning. By the amount of its content, you can determine whether pregnancy has occurred. Also, its level should approximately coincide with the norm of its concentration in the blood in accordance with the stage of pregnancy.
If a woman has pain in the abdominal area, an urgent consultation with a gynecologist is necessary. He will be able to confirm or deny an ectopic pregnancy.
In any case, if a woman sees only a barely noticeable second line on a pregnancy test, it is too early to rejoice. It is worth confirming the result using other diagnostic methods and only after consulting a specialist.
Sometimes something happens completely unexpectedly or comes long-awaited...
Having seen two lines on a pregnancy test, one can make a seemingly logical conclusion about the presence of this very pregnancy. But is it really that simple: a delay, a pregnancy test, two lines and you are a mother?
It just seems that everything is simple, there are many questions and pitfalls. Let's figure out how a pregnancy test works, is two stripes good or bad, and what does this mean in different life situations.
Why does the test show two lines?
Pregnancy tests respond to a hormone that is secreted by the membranes of the embryo (chorion). This hormone is called human chorionic gonadotropin. It is not present in the healthy body of a non-pregnant woman, it appears only when there is a living embryo, gradually its concentration in the blood increases, some of it ends up in the urine, and the action of home pregnancy tests is based on its determination. Two lines appear on the test if a woman is pregnant, but if there is no pregnancy, only one line appears. We have already written in detail what pregnancy tests are and how they work, but in this article we will touch upon issues when such a result seems to not be expected, but it is.
Two bars before delay
What do two bars mean in a situation where you haven’t even experienced a delay yet? Let's start with the fact that you probably started doing this test before the end of the cycle for a reason; you probably suspect something. Maybe your previous periods seemed unusual, you feel nauseous in the morning, or feel weak? Then this test is evidence of pregnancy, and the period may be quite decent, for example, if there is still a week ahead of menstruation, you may already have, if you are pregnant, and, as people say, the previous ones. You need to see a gynecologist.
Two stripes after abortion
You, several days have passed, but the test showed two stripes? Don't be alarmed, this happens. This occurs because human chorionic gonadotropin takes time to clear from the body. Just don’t forget about a follow-up examination by a gynecologist. The second strip should become less and less bright with repeated tests, but if it does not change... Anything can happen. Abortion, especially very early, sometimes it is not complete.
Two stripes after menstruation
If everything was as usual, why did you buy this test? Again, something probably didn't seem right. Or were your periods unusually scanty, short or long, or were you experiencing pain? A positive result indicates that you are likely to be pregnant, and it is not progressing normally, there is