All About Pregnancy Tests

The test for home self-determination of pregnancy is a convenient and useful invention of mankind. Tests have been around for a long time, but they were not at all similar to what women use today. These were flax fibers, herbal decoctions, after the adoption of which women, according to their well-being, should have understood whether pregnancy had come or not. In the form in which test systems exist now, they appeared only in the eighties of the last century. And a lot has changed since then.

The easy-to-use tests have special nuances that you need to know about in order to get accurate and reliable results.

What is it: we understand the principle of work

A pregnancy test is a device or device that is equipped with an absorbent layer and an area for applying a special chemical reagent that is sensitive to the presence of the hCG hormone in a woman's urine. If there is a pregnancy, then the level of this hormone is increased and the test signals this by the presence of a second strip, a plus sign or in another way provided for by the design and modification of the device. If the level of the hormone is low, it is quite easy for the reagent to react with it, and there is no corresponding signal.

In all people, chorionic gonadotropin can be present in the body, but in small quantities - from 0 to 5 mU / ml. Tests do not detect such a level, since they are initially created with the expectation of high concentrations of the hormone. When conception takes place, the embryo will begin its journey into the uterine cavity, which will take him about three days. For some time he will swim in the uterus in search of a permanent "place of residence." On the 6-9th day after conception, implantation occurs: the ovum sticks to the inner wall of the uterus, and thin chorionic villi are introduced into the bloodstream of the mother's body. From this moment, the baby begins to receive nutrition from mother's blood, and the first increased doses of hCG begin to enter the woman's blood.

Chorionic hormone is necessary for the female body as a signal that pregnancy has come. Under its action, the corpus luteum, which forms in each ovulatory cycle on the surface of the ovary, does not stop working and exists, where there was a bursting follicle with an egg. The corpus luteum actively supplies the body with progesterone, menstruation does not occur, pregnancy develops.

HCG levels rise gradually. It first becomes visible in the woman's blood. A little later - in the urine. Every 48 hours, the concentration of this substance approximately doubles. One week after implantation or two weeks after ovulation, the level of hCG in urine reaches the average sensitivity threshold of the reagents that are used to produce the tests.

By the beginning of the delay in menstruation and immediately after it, the test systems are able to capture hormone molecules in the urine, which makes it possible to determine pregnancy in the early stages.

What are they?

There are several types of test systems that differ in price, design, instructions for use. But they all have something in common - the principle of operation. The principle described above is equally true for any test, whichever you choose.

Test strips

These are the most common systems. Simple and practical, inexpensive, disposable. The express test in the form of a strip allows you to get the result in 5 minutes. The stripes have three parts. One is needed in order to hold the test, the other two are located at the opposite end. The test part is impregnated with a reagent sensitive to hCG, while the control part indicates the performance of the strip. In it, it always appears as soon as a serviceable and usable strip-strip comes into contact with liquid media. In the test area, a strip appears only in the presence of hCG molecules in urine in the concentration required for diagnosis. The strips are considered first generation tests.

Tablet (cassette)

These are the same strips, but securely packed in a plastic case. The reagent application area is less exposed to air and cassette variants are considered to be more accurate than strips, although in practice there is not much difference. The cassette has two windows. One is for urine application. This is done with a special pipette included in the kit. The diagnostic result will appear in the second window after the allotted time. Tablet devices are for single use only. They are second generation test systems.

Inkjet

These are more accurate and easy to use third generation tests. They are very convenient: you do not need to collect urine, apply it somewhere... It is enough to bring the test under the stream of urine during urination for 5-7 seconds and get the results in a few minutes. The urine is absorbed by a special tip, after which the applied reagent determines the presence or absence of particles of chorionic gonadotropic hormone in it. Most inkjet systems are disposable.

Electronic (digital)

This latest achievement is called the fourth generation test. Electronic devices work on the principle of jet tests, it is enough to bring them under the stream of urine to get the result in 1-3 minutes. Some tests of this line have an additional second sensor, which determines the quantitative indicator of the hormone and, based on it, gives the approximate gestational age in weeks from the moment of fertilization.

Digital tests are reusable. The kit includes only replacement tips. A new tip is needed for each test. A total of 20 cartridges are included.

In addition to the difference in design, tests are divided by sensitivity level into:

ultrasensitive - determine in urine hCG molecules at a concentration of 5 to 15 mIU / ml;
sensitive - 20 mIU / ml;
medium sensitive - over 25 mIU / ml.

All this information is indicated on the packaging. More sensitive systems allow detecting an elevated hormone earlier than moderately sensitive ones. This is very important for those who do testing before the delay begins.

What is the credibility?

The reliability of test systems is the first important nuance that you need to know the truth about. Manufacturers write that the diagnostic accuracy is 99%. The only method that has such accuracy today is laboratory study of blood plasma for the content and amount of the hormone hCG.

As for express systems for home diagnostics, then the accuracy, according to various estimates, is no more than 95%... The World Health Organization states that the average probability of error with the correct home test is 5%. It is impossible to say how accurate this or that test is. It is believed that inkjet and digital systems are more accurate today. However, many people think that such statements are just a marketing ploy by manufacturers, since it is inkjet and electronic tests that are the most expensive.

The veracity of the test does not depend on its model, price, principle and method of use. Rather, it is directly related to when and how the self-examination was performed. Before the delay, the accuracy is less than after it. For example, 5 days before the date of the expected menstruation, the accuracy, according to the manufacturers themselves, does not exceed 56%. True, this is indicated in the instructions after the asterisk in small print, and on the package it is written in large noticeable letters that the device can be used even 5 days before the start of the delay.

Most often, women get false negative results: there is only one streak, but there is actually a pregnancy. A false pregnancy, when there are two strips, but the baby is not really there, is a rather rare situation. It is possible to count on the maximum accuracy and reliability allowed for the test only after the menstruation has not come within the expected time frame.

The higher the level of the hormone in the urine, the more likely it is to get accurate data.

Contraindications

As such, there are no contraindications to self-diagnosis of pregnancy. This procedure can in no way harm the female body. But there are situations in which it makes no sense to conduct a test due to the too high probability of error.

This applies to all situations in which a woman has an elevated level of the hCG hormone for reasons that do not indicate pregnancy as such. This happens in some forms of malignant tumors that produce this hormone on their own, as well as in the treatment of infertility, if a drug of human chorionic gonadotropin was used in the therapeutic regimen. Such an injection is administered once when ovulation is stimulated by hormonal agents. The same drug is administered before follicular puncture in the IVF protocol.

Therefore, after the treatment protocol, hCG in the woman's blood is increased up to 14 days, and sometimes longer, it depends on age and metabolism. The tests will be positive, but this does not mean pregnancy. In other cases, there are no significant contraindications to testing.

When can I take a natural conception test?

Timing of diagnostics is the most important condition for obtaining the most accurate results.... Very often, false or questionable results are associated precisely with the violation of the recommended terms. Test system manufacturers recommend starting testing for the first time after the delay begins: from the same day, the next, and beyond. But women planning pregnancy, like no one else, know how hard it can be to languish in anticipation of two whole weeks after a favorable period for conception.

So let's look at what the earliest time frame is when you can try to get accurate results. After intercourse, conception can happen both on the same day and after 3-5 days, because this is how much sperm live. therefore it is better to count the time from the day of ovulation - it usually occurs two weeks before the start of the new menstruation. Please note that they count precisely from the end of the cycle, and not from its beginning. Fertilization always occurs only during ovulation or one day after it. Then the egg cell dies if the meeting with the sperm does not take place.

For three days the embryo moves along the fallopian tube, for about 1-3 days it is in the uterine cavity, but in a state of free swimming. Implantation takes place only 6-9 days after fertilization. And only after that does the level of the hormone begin to rise. Thus, in the first 8-9 days after ovulation, there is no point in doing a test. With 10 DPO, you can try to do ultrasensitive tests, a couple of days before menstruation - sensitive ones, from the first day of the delay and later - ordinary ones.

With a regular cycle

If your cycle is regular, there will be no problem calculating the due date. But you should always leave a small margin of time so that ovulation might happen later than expected. This happens periodically even in perfectly healthy women. In this case, you can also start the test from 10-11 DPO (the day after ovulation), and if it does not show anything, then repeat the diagnosis in a couple of days.

With an irregular cycle

If the cycle is irregular, then it can be difficult to calculate the day of ovulation itself. It is optimal to use not calendar methods of counting, but special ovulation tests, which quite accurately indicate the approximation of the release of an egg by the presence of luteinizing hormone in the urine, the peak values of which occur in a short period before ovulation.

If this was not done, then the test should be done after the delay. In the absence of menstruation and a negative result, you can repeat the test after 2 days or do a blood test for hCG, which, in the case of an irregular female cycle, will be the most preferred diagnostic method.

Situations with an irregular cycle should also include breastfeeding cycles. It is also better for a nursing mother to have a blood test.

When can I have a test after IVF?

A test after the IVF treatment protocol is not recommended at all. This is due to the fact that the woman receives an injection of hCG before the oocyte puncture for their early maturation. And it is for this reason that the hormone is increased in the blood plasma, regardless of whether pregnancy has occurred or not.

After transferring the embryos to the uterus, exactly two weeks are counted. Five-day embryos are implanted a little faster than three-day embryos, but sometimes this difference is not so significant. Two weeks after embryo transfer, a blood test for hCG should be done. If necessary, repeat after 48 hours to observe the level in dynamics. When getting positive progressive values an ultrasound scan should be done a week later to confirm pregnancy.

Is the time of day important?

If the delay is already in full swing, then the time of day for testing does not matter. Do the test when it suits you. But earlier, before the delay, it is better to test in the morning, right after waking upusing the first portion of urine after waking up for self-examination.

What kind of urine can I use?

Manufacturers advise women to use the morning urine sample for diagnosis. Especially when it comes to early periods before the delay, when the hormone level is relatively low. The first urine after waking up is more concentrated, dense, the amount of hormones in it will be more noticeable for a chemical reagent.

If the delay has already lasted for several days, you can use any urine during the day, since the level of chorionic gonadotropin by this time is usually already high at any time of the day. It is only important to remember that you will get a more accurate result if you do not urinate for 3-4 hours before the test, drink a lot of liquid.

For the test system, it is not the amount of urine itself that is important, but the concentration of the desired substance in it.

Instructions for use

If you bought a regular strip strip, its use should not cause you significant difficulties. The algorithm is pretty simple:

collect a portion of urine in a clean container;
open the packaging with the strip, check that it is intact and undamaged;
dip the strip into a container with urine to the level indicated as the control MAX;
hold the strip vertically for the time described by the manufacturers, as a rule, this is 15-20 seconds;
remove the strip and place it on a dry and level surface for 5 minutes, then evaluate the result.

Important! Do not lower the strip deeper than the marked line, do not keep it in the urine for too long, and do not overstretch to evaluate the result. If this is done not after 5, but after 25 minutes, unreliable changes are not excluded - for example, the appearance of a gray ghost band, which in its essence is simply a visualization of the place where the chemical reagent was applied.

When using cassette tests, special subtleties are not required. The only thing that requires responsibility is the process of applying urine. As with strip strips, urine should be collected in a clean container. Further, the algorithm of actions is as follows:

pick up the liquid with a special pipette and put 3-5 drops in a special window;
Leave the cassette in a level and static position for 5 minutes, after which you can start evaluating the results.

If you are using a jet test, the procedure will be slightly different from those described above:

open the package and assess its integrity;
remove the cap from the test;
bring the tip under the stream of urine for 5-7 seconds while urinating;
replace the cap and place the test on a flat surface for 3 minutes;
evaluate the results.

Important! It is strictly forbidden to hold the device vertically, tip up. Either hold the absorbent side down or lay it on a horizontal surface. Digital and jet tests can also be used with preliminary urine collection, if desired. But in this case, you need to hold the tip in the container with urine a little longer - up to 20 seconds.

The electronic test is very simple to use. You need to turn it on, make sure that the device is ready for use, bring it under the stream of urine or lower it into a container, after which an hourglass sign will appear on the display. Do not turn off the device, do not shake. The clock in this case symbolizes the process of analyzing the collected data. After 3 minutes, the test will give you an answer with the words "Pregnant" or "Not pregnant", and if it has the function of determining the term, it will also show it in weeks.

Deciphering the results, the location of the second strip and its brightness

The question of interpretation is quite acute, despite the seeming simplicity of this process. A positive result should be considered a result in which two clear, equally bright stripes appear on the test strip and cassette test. One is located in the test area, and the other in the control. On the jet test, a fairly clear "+" appears, and the digital test says "Pregnant."

A test in which there are two stripes, but one of them is weak, indistinct, blurred, is considered weak or doubtful. Such a result may be an early pregnancy, when the level of the hormone is not yet so high for the reagent to fully react, but not so small that there is no reaction at all, as well as a consequence of an incorrect test. Sometimes just such weak second stripes indicate some pathologies of the onset of pregnancy. This will be discussed below.

It should be noted that digital and inkjet tests show no weakly positive conclusions. There are only two options: either "yes" or "no". “Maybe” as an answer is not provided by the creators.

A negative result is one clear and distinct line in the control area. The absence of the second one in the test indicates that the reagent could not be found in the desired concentration of hCG molecules. Inkjet models will show "-", and digital models will write "Not pregnant" with all directness.

Another option that is considered the rarest is no stripes at all. He talks about test unsuitable for use: the product is expired, the reagent layer is damaged, the electronics in digital models are damaged.

In general, you need to get a new copy and repeat all over again.

What influences the correctness of the result?

Of course, the correctness of the verdict that you receive is influenced by how accurately you follow the instructions for use. Violation of rules of use is a common reason for a false positive or false negative result. Therefore, do not rush, read the instructions carefully. It is written for a reason, but specifically so that you know it.

Beware of wetting the test with water before diagnosing, do not drop or drop it during the drying period before reading the results, try not to drink a lot of water before diagnosing, and do not use systems with low sensitivity until the delay. This is quite enough to count on getting a truthful verdict. But there are other circumstances that can influence the response.

The minimum terms have been violated

Most often, women get untrue, erroneous results if they are in too much of a hurry to find out the truth, they do everything ahead of time. It is necessary to clearly understand that in all situations without exception, in the first week after conception, until the embryo is implanted, the chorionic gonadotropin simply has nowhere to come from, and the hormonal background of pregnant and non-pregnant women begins to differ from each other only in the last days before the delay.

There is no sense in the test earlier than 5 days before the start of the delay. And if we do not exclude that there is always a possibility of later ovulation and late implantation, then by the beginning of the delay there may be negative results, even if the conception did happen.

If you desperately need an answer to a question as early as possible, it is better to abandon testing and use alternative methods, which will be discussed below. If time is running out, wait for the start of the delay.

Late or too early assessment of the result

Violation of the requirements of the time intervals allotted by the manufacturer for the assessment of the result often leads to misunderstandings. A common situation: the test was negative, and after half an hour the lady looked, and there was a second one, but very, very weak. Further, women attach a photo of this second and ask them to tell if it is it or not.

In 99% of cases, this is really the second strip, but, alas, she does not speak about pregnancy. After drying, the test is no longer valid, unsuitable for reuse, and a grayish second stripe appears in the place where the reagent was applied. In this case, the result will be negative, and it is the late interpretation that confuses the woman, gives her false hope and ultimately leads to terrible disappointment when the next menstruation comes on time.

Early Interpretation is a cursory assessment of the test before the timeout expires. The woman did a running test, then, without waiting 3-5 minutes, she evaluated one strip that appeared, threw out the test and ran longer. She will not see how, after the allotted five to seven minutes, a second strip appears on the test, which will change everything in the life of the fair sex.

Time of day not taken into account

If the delay has not yet arrived, then the time of day plays an important role. During a night's sleep, the kidneys continue to work, urine accumulates in the bladder, and the first morning urination allows you to get urine with a maximum content of all structural elements and impurities. By the way, for the same reason doctors recommend taking a urine test in the morning.

If the delay has already lasted for several days, the time of day does not matter. The hormone is elevated throughout the day and night and continues to rise.

Test expired

Most women consider shelf life to be an important characteristic for milk, meat, and cheese. This is true, but for the test, the shelf life is very important. If the test is overdue, then the reagent in its test area may partially or completely lose its chemical properties, which significantly increases the likelihood of obtaining unreliable results.

Therefore, carefully study the expiration date before buying.

Effects of disease and medication

Only the hCG drug administered to a woman earlier can significantly affect the accuracy of the test system. If this remedy has not been used, there are no special restrictions on medications. Test can be done against the background of the reception of "Utrozhestan" and "Duphaston", as these drugs contain progesterone and not hCG. Self-diagnosis is quite accurately carried out against the background of taking antibiotics, pain relievers, antiviral drugs, antihistamines and others. The intake of such medications does not affect the level of hCG in any way. Even contraceptive drugs taken in the current cycle, recently canceled oral contraceptives are unable, due to their composition and principle of action, to influence the chorionic gonadotropin.

Accuracy may be slightly reduced in case of pyelonephritis, cystitis in the acute stage. In a chronic disease of the urinary system, influencing factors are not detected. With an acute ailment, a woman cannot hold urine for a long time, urination is frequent, painful, the concentration of urine is weak, and therefore it is difficult for the reagent to detect hCG in the proper concentration.

Nausea does not affect the result, there are no significant changes in endometriosis. Tests for hormonal failure may be unreliable, but the likelihood that it is the production of hCG that will be the factor of failure is low. If the failure occurs by itself, outside of pregnancy, then negative test results are considered quite reliable. The influence of oncological malignant neoplasms is also possible. If there are any, the level of hCG can be increased without pregnancy.

In case of implantation bleeding, the test is also reliable, although it is too early to do it during this period. Only two days after implantation, the level of the hormone will begin to increase in the blood, and then in the urine. The presence of bleeding, menstruation is not an obstacle to testing, if there is a need for it. Also, there is no particular expediency in testing for menopause, but a woman, in case of personal need, can do a test and get her result, since the hormonal background during the extinction of ovarian function does not affect the level of hCG in the body.

The influence of alcohol

Alcohol intake by a woman does not affect the test results. The only thing worth warning against is a large amount of alcoholic beverages that cause frequent urination. In this case, the urine will be less concentrated, which may affect the response of the test system at the earliest possible date. It is also possible to drink a lot of water after drinking alcohol at night, which will further reduce the accuracy of the test.

Increased hCG levels in men and non-pregnant women

The reasons why the level of hCG may be elevated in women and men, if you do not take into account pregnancy as such, are few. In a woman, this may be due to a recent termination of pregnancy. The hormonal background after an abortion, miscarriage remains unstable for a long time, and the level of accumulated hCG at the time of termination of pregnancy decreases slowly and gradually.

The rise in hCG can cause blistering in women - a condition in which there is no embryo as such, there is no embryo, and the chorionic villi grow in the uterine cavity. In men and women, the level of chorionic gonadotropic hormone increases with malignant tumors.

Decreased hCG levels in pregnant women

Decreased hCG levels during pregnancy usually have pathological causes. On the test, this is indicated by either a weakly positive test that does not get brighter over time, or a negative test in an actual pregnancy. The reasons may lie in the pathology of embryonic structures, in which the chorionic villi do not cope with their duties. Usually, these violations are of a rough chromosomal nature, and in most cases such embryos are not viable, the pregnancy is terminated by itself in the early stages.

A decrease in the amount of hCG is due to the threat of miscarriage outside the pathologies of the embryo. The reasons for the threat can be very different. Also, ectopic and frozen pregnancies are characterized by a reduced level of chorionic gonadotropin.

Ectopic or missed pregnancy

If the embryo is attached not in the uterus, but in the tube, in the isthmus or cervix, then chorionic gonadotropin is also produced, but in much smaller quantities than in a full-fledged normal uterine pregnancy. Therefore, for a long time the test can remain negative or be weakly positive without a noticeable increase in the brightness of the second strip.

The last week before the onset of the delay is equal to 3-4 obstetric weeks, and it is the first critical in terms of the likelihood of a missed pregnancy. For what reasons the baby stops growing and dies, it is difficult to say, all this has not been sufficiently studied, but the fact remains. In this case, you can get a positive test result, and after a while - weakly positive and negative. The level of hCG decreases gradually after the death of the embryo.

How do you know if the test was working?

If we are talking about conventional strips, then the presence of a control strip is important. It is present on both positive and negative tests. Its absence suggests that the test was either defective or expired. The control line is the first strip that appears after the system gets wet.

The control zone also contains jet tests. And digital ones carry out diagnostics of the device's performance before and after testing in automatic mode.

Remember to check the control area and expiration dates.

Should the results after pregnancy termination be believed?

After termination of pregnancy for at least one menstrual cycle, the hormonal background remains unstable. Elevated hCG can be present in the blood and urine of a woman for up to 2 weeks, and in some, up to a month. There is no significant difference in which way the pregnancy was terminated: there was a miscarriage, there was a medical abortion, or the termination of pregnancy was performed by a vacuum or surgical method. Tests during the month following the interruption can give false positives.

Review of popular brands and models

Brand tests are very popular among women Clearblue... This British company presents not the cheapest, but rather accurate and solid diagnostic systems. There are strips in the case: Clearblue Compact, Clearblue Easy Read. There is an inkjet Clearblue plus and reusable digital Clearblue digital with the function of determining the duration of pregnancy in weeks. It should be noted that digital tests are currently produced only by Clearblue. Other firms specialize in disposable and cheaper options.

Among the fairly popular and solid tests, the product line can be noted Frautest and Evitest. These firms are ready to offer products for any budget: from inexpensive strip strips to more expensive cassette and inkjet options.

There are also Russian tests that have proven themselves well: “I was born”, “Test Mom”, “Vera”, “Eve”. Russian firms almost do not produce inkjet models. But on the other hand, they make a large selection of strip strips and tablet models at the lowest price for the end consumer.

What tests are suitable for early diagnosis?

For the earliest diagnosis, ultrasensitive tests are suitable, on the packaging of which the hCG threshold is indicated in 5, 10 and 15 units (mIU / ml is the unit of the presence of the hormone in urine, do not confuse it with the unit of the presence of the hormone in the blood). Study the packaging carefully, find the sensitivity threshold and it will become clear whether or not the test can be used before the delay of menstruation.

Once the delay has begun, systems with any sensitivity can be used, even above 25 mIU / ml.

Tips for choosing

When choosing a test, do not pay attention to cost - it is not considered an indicator of accuracy. Even the cheapest test can be more effective than an expensive device.

Let's consider a few additional recommendations:

do not take tests in stores at the checkout - there are no adequate storage conditions;
buy test at the pharmacy;
check the sensitivity threshold on site - if you are at a loss, seek help in resolving this issue from a pharmacist;
check the expiration date and inspect the packaging - it should not be damaged, crumpled, open.

Expiry dates

The shelf life differs from test to test. On average, it is 2 to 3 years from the date of production. remember, that an overdue test cannot guarantee you accurate and reliable results.

Review overview

Every brand and every brand has positive and negative reviews. But in general, women note that after the start of the delay, there is no need to overpay for expensive tests with a bunch of additional functions and beautiful design. And the most common strip will give quite intelligible answers to all questions.

Folk remedies (iodine, soda and white wine) today should not be used to determine pregnancy: the cost of the ingredients may be more expensive than the price of the test. In addition, folk remedies have no reliability and effectiveness. It is almost zero.

Alternative diagnostic methods

The only alternative and more accurate method than tests is a blood test for hCG. It can be done in any clinic on an empty stomach, about 9-11 days after ovulation and later. Price - 300-600 rubles. You will receive a clear answer to the question of whether there is a pregnancy, as well as whether it is developing normally. By an accurate quantitative indicator, an ectopic, frozen and multiple pregnancy can be suspected.

Can you trust online tests?

There are many tests on the Internet that offer to determine pregnancy. They are based on a series of questions about the symptoms and the date of menstruation, answering which, a woman will receive an approximate answer like "pregnancy is likely" or "pregnancy is most likely not."