Can A Pregnancy Test Be Wrong?

2024 Author: Josephine Shorter | [email protected]. Last modified: 2024-01-07 17:49

Can a pregnancy test be wrong?

Modern rapid tests are one of the most reliable early pregnancy diagnostic systems. However, as statistics show, about 25% of women are unsure of 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 can diagnose pregnancy already on the first day of missed periods, and sometimes even earlier.

A special substance is applied to the test, which, reacting with the hCG hormone from urine, turns into a bright color. If the test is equipped with an electronic scoreboard, then the test result appears on it in the form of the words "pregnant", "not pregnant" or in the form of signs "+", "-".

Content:

• Why can a negative pregnancy test result be false?
• Why can a positive pregnancy test result be false?
• Common reasons for getting an invalid pregnancy test result
• Which pregnancy test gives the most reliable result?
• How do I check my pregnancy test result?

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 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 performed the test too early. Some systems allow you to diagnose pregnancy 4-5 days before your period starts. However, in this case, even the manufacturers themselves warn about the possibility of obtaining a false negative result.
• The woman has an irregular menstrual cycle, resulting in a calculation error. 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 pick it up. However, testing at a later date (7-14 days after the delay in menstruation) will reveal an existing pregnancy, even if it is ectopic.

Sometimes the test gives a false negative result when using highly diluted urine for the study. This happens while taking diuretics or other diuretics, as well as when a woman drank a lot of fluids during the day. This is especially true in the case when the research is carried out early. Therefore, all doctors give an unambiguous recommendation: to perform testing in the morning, immediately after waking up.

Another reason for a false negative pregnancy test result is serious kidney disease, which is accompanied by renal 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?

Getting a false positive result is also possible, but the reasons will be slightly different, among them:

• A woman takes medications that contain chorionic gonadotropin. These drugs include the drugs "Pregnil", "Ovitrel" and "Profazi". They are prescribed for 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 may remain high after a miscarriage, a removed ectopic pregnancy, or an abortion. On average, the hormone levels return 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, 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.

• The woman entered menopause. Sometimes during menopause, the level of hCG rises to 14-15 mIU / ml, which is a physiological phenomenon. At the same time, pregnancy tests with high sensitivity can give a positive result, which will be false.

A weak and dim second band on the test is regarded as a positive result. However, in this case, the testing procedure is best repeated after a few days. This will make it possible to clarify the answer received, or to timely identify any pathology (for example, an ectopic pregnancy).

Common reasons for getting an invalid pregnancy test result

It is possible that the test may be erroneous due to its own malfunction. This happens if a poor-quality test was purchased. As a rule, the risk of buying a fake increases in the case of expensive devices. Therefore, do not hesitate to ask the pharmacy for a certificate for the product. It is highly advisable to buy tests at proven points of sale.

When purchasing a test, pay attention to the expiration date of the device. This information is always indicated on the packaging. Buying an expired test may lead to the test result being unreliable or the test may not work at all. A similar situation can occur when tests were stored incorrectly.

Another reason for getting an erroneous result is non-compliance with the instructions for use. Although the rules for the procedure are very simple, they should be strictly followed. In general, all devices are used according to the same type of scheme with minor differences. The testing procedure requires exposure to the urine test. The cheapest and simplest test strips are simply dipped into a container with pre-collected urine. Tablet tests require putting a few drops of urine into a special window, while for jet tests, you just need to urinate for 5 seconds.

In order for the test to produce the most reliable results, the following rules must be observed:

• The container for collecting urine must be clean and dry.
• Testing should be done in the morning.
• Before collecting urine, it is advisable to wash with soap and dry with a towel.
• The test must be removed from the sealed packaging.
• Research should be carried out immediately after opening the device.
• The test should be kept in the urine for as long as indicated in the instructions for it.
• It is necessary to immerse the test in urine up to the line that is marked on the device.
• The result must be assessed within the time period specified in the operating instructions.
• Only fresh urine should be used for the study.

Sometimes it happens that the test was positive, and after some time it became negative, or vice versa. That is why the manufacturer always indicates in the instructions for use the time for which it is necessary to evaluate the result. Typically 10 minutes for test strips. As for electronic tests, their scoreboard remains active throughout the day, after which it goes out.

Another common situation that many women face is getting a positive test result, which can turn negative after a few days or weeks. In this case, there is no need to talk about a test error, especially if the study was carried out repeatedly and using different devices. In fact, the woman had a pregnancy, but very often it happens that she ends up with a miscarriage in the early stages. Moreover, the woman herself does not even notice this, since everything happens according to the type of normal menstruation. Therefore, the test after a few days gives a negative result, and there is no question of an error.

Which pregnancy test gives the most reliable result?

All test manufacturers are assured that their products are 99% accurate under the conditions of use. It is quite difficult to verify this. Nevertheless, as practice shows, there are certain nuances that largely depend on the type of pregnancy test.

The most common tests are strip strips, which are very easy to use, have an affordable price, but also the lowest reliability. The inaccuracy of the results is due to the fact that the strip in the urine can be accidentally overexposed, underexposed, immersed below the prescribed level, etc. In addition, when using inexpensive devices, the strip is very often blurred, which occurs due to the transition of the coloring pigment from the control to the test line, which is responsible for assessing the result. Therefore, when buying a strip-strip, a woman needs to be prepared for such "surprises".

The second type of tests is tablet (cassette) tests. These devices are considered to be the most accurate, since the study is as close as possible to the diagnosis of pregnancy at a professional level. A few drops of fresh urine are introduced into one of the windows. This is done using a special pipette. Then time is waited and the result is evaluated. In this case, the probability of error is minimized. It should be noted that the price for such tests will be an order of magnitude higher than for strip strips.

The third type is inkjet tests. To conduct a study, simply substitute the device under the stream of urine. The result will be displayed on an electronic scoreboard. Compared to other tests, jetting systems are usually the most sensitive and allow the test to be performed several days before the onset of the expected period.

How do I check my pregnancy test result?

In general, a woman should have no reason to doubt the reliability of the test results. Moreover, tests are actually very rarely wrong. However, if doubts still remain, then you can test again, strictly following the instructions for use. It is best to leave 2-3 days between the first and second tests. When the result obtained again does not satisfy the woman, it is necessary to consult a doctor.

You need to understand that the only irrefutable proof of pregnancy is the result of ultrasound diagnostics. Only with the help of ultrasound can you see the ovum and confirm pregnancy. Therefore, if a positive result is obtained, it is necessary to conduct the study again after three days. If the test is again positive, you need to contact your gynecologist.

A visit to the doctor should also end such a situation in which a pregnancy test gives a negative result, but menstruation does not occur.

So, there are a lot of reasons that can provoke an unreliable pregnancy test result. To minimize the likelihood of error, you must strictly follow the instructions and carry out the procedure on time.

The author of the article: Lapikova Valentina Vladimirovna | Gynecologist, reproductologist

Education: Diploma in Obstetrics and Gynecology received at the Russian State Medical University of the Federal Agency for Healthcare and Social Development (2010). In 2013 completed postgraduate studies at N. N. N. I. Pirogova.