To begin, let's try to hold a little experience. Take a strip of filter paper with a length of about 10 cm and a width of about 1-1.5 cm (a blotter will fit, and even a piece of toilet paper, napkin or paper towel) and at a distance of about 1 cm from the edge apply a thick point with a water soluble black felt-tip pen or Rainbow ink or horizontal line. Now dip this end into the water so that the plotted point barely touches the surface of the water, and hold it. You will see how, under the action of capillary forces, water rises along a paper strip, dragging ink along. Very soon you will notice that the black spot is spreading on three: red, blue and green. When the water reaches the end of the strip, pull it out of the water.
] The phenomenon of the separation of a mixture into components when moving them with a current of solvent along a porous carrier was discovered about 100 years ago by the Russian scientist M.S. Color just on mixtures of dyes and called them chromatography, or color painting.
If for the experience to take strips of the same paper of the same length (at the same temperature and humidity), you can see that the colored spots are always located at the same height. This fact is used in test strips.
Human urine contains in solution a huge amount of substances, including hormones. Most of these substances are colorless and, it would seem, chromatography is useless here - after all, we will not see spots on the strip. However, we can put on those places where we expect to see the substances of interest to us, special developers, which give a noticeable bright color with the substance to be detected.
This is how tests are arranged not only for pregnancy, but also for other hormones, drugs, and the once popular test strips for nitrates in vegetables, and much more.
Immunochromatography is used in pregnancy tests, a type of chromatographic analysis based on the interaction of the analyte (usually of a protein nature) with its antibodies. According to the same principle of antigen-antibody interaction, the body’s immune system works, hence the name.
The substance identified is human chorionic gonadotropin (hCG) - a glycopeptide hormone secreted by the placenta during pregnancy. The appearance and rapid increase in the concentration of hCG in the body (and in particular, in the urine) of a woman makes it a fairly reliable sign of pregnancy.
Usually on the 7-10th day after fertilization, the concentration of hCG reaches 25 mIU / ml (international units per ml) and doubles every 2-3 days, reaching a maximum between the 8th and 11th weeks of pregnancy, and then decreases to almost zero to the beginning of the 3rd trimester.
25 mIU / ml is the minimum concentration of HCG determined by immunochromatographic tests.
The test strip contains a conjugate (weak connection) of antibodies to hCG with a dye. When a urine sample moves along an absorbent strip, the conjugate binds to hCG and forms an antigen-antibody complex. In the zone of positive reaction ("pregnant strip"), the complex binds to anti-hCG antibodies. When this occurs, the dye is released and a red-pink strip is formed.
If there is no hCG in the sample, no strip, of course, is formed.
In the meantime, urine moves on, passes the positive reaction zone and reaches the negative reaction zone (“control strip”). There, the unbound antibody-dye conjugate is bound by the control strip reagents, the dye is released and a second (control) strip of the same red-pink color is formed.
All reactions occur within 3-5, less than 7 minutes.
In not very high-quality tests, the dye can be chipped off from the conjugate earlier than the entire complex of antibody-hCG-dye reaches the reaction zones, forming blurry spots. They are often taken for a “false positive” result. Real false positive results are much less common and are caused by quite specific reasons. A weak second bar can also appear if you overdo the test, i.e. read readings not through the 5 minutes indicated on the package, and later. Such a line arises from the evaporation of water from the surface of the dough, from which the conjugates are destroyed and the dye is released. So you should not wait 10 minutes instead of 5, to "surely make sure."
Since not every woman can accurately follow all the instructions and correctly interpret the test results, doctors, especially the old school, are not inclined to trust the tests.
WHAT DETERMINES A PREGNANCY TEST?
The pregnancy test determines human chorionic gonadotropin (hCG) - a hormone secreted by the placenta since the implantation of the embryo into the uterine wall throughout pregnancy. The reliability of this test is very high - no placenta, no and CG. HCG can be determined both in blood (in the laboratory) and in urine (in the laboratory and at home).
FOR WHAT DAY AFTER OVULATION CAN YOU TEST?
In principle, a positive result can be obtained already on the 7th day after ovulation. An embryo implantation takes 6-12 days, usually about 10 days. So it makes sense to wait 10-12 days after ovulation, but even in this case, there are often false-negative results (i.e., there is a pregnancy, but the test is negative).
WHAT DO FALSE-POSITIVE AND FALSE-RELEVANT TEST RESULTS MEAN?
False positive result - this is when the test shows two strips in the absence of pregnancy. This happens when a woman takes drugs containing hCG, as well as with trophoblastic tumors. After a spontaneous miscarriage or abortion in the early stages or the removal of an ectopic pregnancy, hCG remains in the body for some time, and the test gives false-positive results (ie, there is no pregnancy, and the test is still positive).
As in the case of taking drugs containing hCG, to obtain reliable results, it is necessary to make two quantitative determinations of hCG with an interval of 2-3 days. The decrease in the level of hCG indicates that there is no pregnancy.
Thus, false-positive results are a relative rarity, as opposed to false-negative ones. The latter are obtained when the period of pregnancy is still too small and the level of HCG is too low for the test to detect (or the test itself is not sufficiently sensitive).
WHAT IS THE RELIABILITY OF PREGNANCY TESTS WHEN USING MONTHLY MONEY DELAY DURING THE FIRST DAY?
Tests of different manufacturers have different sensitivities, most of them are designed for use from the 1st day of the monthly delay. In 90% ± 5% of cases by this time the embryo is already implanted in the wall of the uterus and begins to produce hCG. However, in 10% of cases, implantation has not yet occurred.
With a delay of 1 week, implantation occurs already in 97% ± 3% of cases. However, in practice, the reliability of tests is limited by their sensitivity, so that the real reliability is somewhat lower.
Since the level of hCG doubles every 2–3 days, the recommendation follows: with a negative result, if the monthly periods do not start, repeat the test after a few days.
HOW LONG DO I NEED TO SAVE URINE TO BEFORE THE TEST?
It depends on the time elapsed since ovulation. The most concentrated urine - the first morning, it is best to use it. But in principle, if you are tested early, it is enough not to urinate for 4 hours before the test. The higher the level of hcg in your body, the less this time. If for any reason the test cannot be carried out immediately after collecting the urine, before the test the urine should be stored in the refrigerator (no longer than 48 hours) or in the freezer (no more than 2 weeks).
HOW IT IS CORRECT TO PERFORM ANALYSIS?
Follow the instructions on the dough packaging. Tests like "midstream" (for use in a stream of urine) can be used as a normal test (i.e. dipping into a container with urine), but then all the advantages of the "midstream" construction are lost.
But the test strips in the stream of urine can not be used! Urine should be collected in a clean glass, plastic or waxed container, no preservatives can be added. If the test or urine was stored in the refrigerator, they should be allowed to warm to room temperature before analysis, and the frozen samples should be completely thawed, mixed thoroughly and heated to room temperature (do not use a stove or a microwave for this!).
WHAT ANY MISTAKES SHOULD BE AVOIDED BY TESTING?
It is not allowed to touch the reaction zone of the test. Prior to analysis, no moisture or dirt should enter the test. The test can not be used after the expiration date. Of course, do not allow foreign substances to enter the urine sample. Violation of these rules leads to unreliable results.
WHERE SHOULD THE SECOND STRIP HAVE TO BE LIVED? DOES BRIGHTNESS MEAN?
On the test strips of the simplest design, the upper strip is the control one, and the presence of HCG is indicated by the lower one. There are tests in which the control bar forms a minus sign “-”, and the second, in the presence of hCG, forms with it a plus sign “+”. In more complex test constructions, there is a window for each strip, and it is impossible to err. The brightness of the second bar does not matter, the fact of its presence is important.
The strip, regardless of the intensity of color, should be located at some distance from the absorbent pad (or the edges of the window) and have clear edges. If instead of a clear line you see a pink spot, the test is invalid. However, if in doubt, it is better to repeat the test after a few days.
CAN TEST READINGS CHANGE THROUGH ANY TIME, SAY AFTER ANALYZE AFTER ANALYSIS?
A positive result will not change: both strips, as they were painted, will remain so. In a negative result, after 10 minutes or more, a weak second strip may appear as a result of water evaporation and dye release (the so-called evaporation line). This, of course, does not mean that suddenly a hCG appeared from somewhere.
THEREFORE THE RESULTS OBTAINED LATER THAN IN 5-7 MINUTES ARE NOT VALID !!!
A negative result will not be positive either after 10 minutes or after an hour; the second strip should appear during the time specified on the test packaging (usually it is 3-5 minutes). However, if you have doubts, it is better to repeat the test after a few days.
CAN ALCOHOL, DRUGS, ETC. IMPACT ON THE TEST RESULT? Alcohol, medications (and even birth control pills), lactation, menopause, etc. do not affect the test results. The only exception is drugs containing hCG (pregnil, prophazy, etc.). After the last intake of such drugs, you should wait 10-14 days, otherwise the test result will be false positive.
Two quantitative determinations of hCG can be made in the laboratory with an interval of 2-3 days: a noticeable increase in the level of hCG in the second analysis compared with the first indicates pregnancy, while a decrease in the level indicates that hCG administered with the drug is excreted from the body.
ATTENTION! A PREGNANCY TEST DOES NOT ALLOW DIFFERENT NORMAL PREGNANCY FROM PATHOLOGICAL (eg, ectopic) .2) Pregnancy tests may be wrong! Manufacturers of rapid pregnancy tests in one voice promise 99 percent accuracy of the results of their products. However, the reality is somewhat different. As you know, home pregnancy tests can be purchased at any pharmacy. The principle of their action is based on the content in the urine of the "hormone of pregnancy" - chorionic gonadotropin. In just a few minutes, a strip strip reacts to its level of concentration and produces a result in the form of one or two strips.
In most cases, the data of such a test can be trusted. However, women who have been struggling for the desired pregnancy for a long time know that the test can show false positive results. It is not difficult to guess what joy they experienced at the sight of the long-awaited second strip! And what a pain and disappointment brought them a visit to the doctor when it was found that in fact there is no pregnancy.
With the threat of miscarriage, the test can become negative all of a sudden. It happens that a negative result becomes the first sign of a terminated pregnancy. Poor quality test. If a year ago, gynecologists trusted the test results to almost 100, now they prefer to examine the patient and make an ultrasound. There is another option: when setting the test, not a single strip is painted. This means that the test is defective.
The first. When conducting a pregnancy test errors may occur. First, the test begins to work, at the earliest, 10-12 days from the day of conception. This usually means from the start of the delay. Therefore, doing the test on the 15th, 20th, 27th day of the cycle is absurd. Although sometimes it is impossible to wait for the first test to be done the next morning after intercourse ... So, the test done during the last cycle is free to show what it pleases - this is still the wrong result. Wait for the delay. In addition, if intercourse occurred, for example, on the fifth day of the 30-day cycle, then the probability of conception is extremely small (although, of course, there is). However, after 12 days, that is, on the 17th day of the cycle, the test will still give a negative result - and this will be true. Second. Due to minor flaws in the methodology (which is very clearly stated in the package insert for each test), due to the peculiarities of production, storage, transportation, etc. Many tests really start to work correctly only from 8-10 days delay. Therefore, if you have a delay, and the test on the second day does not show anything, do not be lazy to do it again in a week, and even better - donate blood to the HCG. Third. No other hormones, foods, stress, etc. The test result is not affected. Therefore, you should not be deceived, for example, by the fact that the test was made against the background of a delay, immediately after intercourse - this is sperm and gave a false result ... Hardly, the test is more likely to be right. False negative results can only be in women with kidney disease, renal failure, arterial hypertension, vegetative-vascular dystonia, heart failure, aortic atherosclerosis, renal arteries and other diseases in which the blood circulation in the kidneys is impaired. However, in a few days, and in such women, the test will become positive. Fourth. In a thirst for a positive response, many women watch the test behavior not for 5 minutes, as indicated in the instructions, but for two hours! And really, finally, they guess some barely visible striped ... Alas, this is not a result, but the influence of external factors, which in 2 hours make such that no instruction can be foreseen. Fifth. Tests are designed only for work with urine. CG in their blood or saliva is not determined with their help. In any suspicious case, as well as, if very accurate and very early diagnosis of the presence of CG, and its concentration in the blood is necessary, a venous blood test is performed. It is carried out in almost any gynecological institution in one day. The accuracy of this analysis is much higher than the tests, since thinner methods of detecting hormone are used. Therefore, if the presence or absence of pregnancy for you is a matter of life and death, not the third time for tests, immediately go for an analysis. Blood tests for HCG are used not only to diagnose pregnancy as such, but also to track the course of pregnancy and even Establishment of the OPPORTUNITY (but in no way obligatory) of an ectopic pregnancy. There are special tables of CGH concentrations in the blood at each gestational age, and for ectopic levels of CGH is approximately 2/3 of these figures. Therefore, by the way, the test can give a negative result, although pregnancy develops in the tube.
Chorionic gonadotropin is a biologically active substance, a hormone that is part of drugs that are used when there is hypofunction of the female sex glands (decreased activity), as well as the sex glands in men, based on a disorder of the hypothalamic-pituitary system.
pharmachologic effect
Inhibition of the function of the sex glands can occur due to a variety of reasons, including genetic disorders. Such diseases may be of primary or secondary nature. In the latter case, the cause of the disease lies in other factors, one way or another, affecting the processes of growth and development of the sex glands.
Preparations containing chorionic gonadotropin, have a gonadotropic effect, therefore, stimulate the activity of the female and male genital glands - the ovaries and testicles.
The mechanism of action of the drug is based on the activation of gonadotropin-specific receptors, as a result of which the activity of the sex glands is normalized, and other processes that are regulated by testosterone and estrogen are triggered.
The use of chorionic gonadotropin preparations in men helps stimulate the development of the testicles, activates the reactions that underlie spermatogenesis, and therefore, increases the volume of ejaculate. It is a factor in the development of secondary sexual characteristics.
In women, under the influence of drugs, reactions of biological synthesis of estrogens are stimulated, ovulation occurs, secretory activity of the corpus luteum appears, the cycle is normalized, other important processes are activated.
The effect of chorionic gonadotropin is similar to the biological analogue - luteinizing hormone, but unlike the latter, lasts for a much longer period of time, since it is characterized by a longer half-life.
Chorionic gonadotropin preparations are used both for congenital dysfunctions of the sex glands and for those acquired. When cryptorchidism, this substance contributes to the descent of the testicles and the normalization of their functional component.
With the introduction of chorionic gonadotropin, therapeutic concentration is created after 30 - 40 minutes. The half-life is about 8 to 10 hours. Removal of the drug is carried out with urine.
Indications for use
The purpose of the substance chorionic gonadotropin is possible for the implementation of replacement therapy in the presence of the following diseases:
Delayed sexual development;
Anovulatory ovarian dysfunction (no ovulation);
Insufficiency of the yellow body in the luteal phase of the menstrual cycle;
Uterine bleeding in women of fertile age;
Hypogonadotropic hypogonadism;
Testicular hypoplasia;
Eunuchoidism;
Pituitary dwarfism;
Disorders of spermatogenesis.
The use of such drugs is possible only with the explicit approval of a specialist who has the results of laboratory and instrumental studies. Use without proper control, for example, in sports practice, can have extremely negative consequences.
Contraindications
Chorionic gonadotropin should not be administered in the presence of the following conditions:
Oncological pathology of the pituitary gland;
Hormone-dependent prostate tumors;
Mammary cancer;
Lack of sex glands;
Individual intolerance to chorionic gonadotropin;
;
Ovarian cysts;
Early menopause;
Premature sexual development;
Age less than 4 years;
Arterial hypertension;
Migraine states;
Severe pathology of the kidneys.
In addition, do not use the tool for epilepsy.
Application and dosage
The dosage of the drug is determined by the indications for use and the level of luteinizing hormone and can vary from 500 to 10,000 IU. The solution for administration is prepared immediately before use. For dilution, use the supplied solvent. Storage of the finished drug is not subject, therefore, it must be used immediately.
In the absence of ovulation, 3000 IU should be administered intramuscularly from the 10th, 12th day of the cycle. Usually carried out 2 or 3 injections with an interval of 3 days.
Overdose
Given the extremely low degree of toxicity, talk about the possibility of an overdose of human chorionic gonadotropin is not necessary. Such cases in the present period of time are not recorded.
Side effects
On the part of the endocrine glands: reversible increase in the mammary glands in men, water retention, sodium, the appearance of acne, a significant increase in the testicles, premature puberty, atrophy of the testicles or ovaries, a decrease in the number of spermatozoa, the formation of ovarian cysts, multiple pregnancy.
From the side nervous system: depression, constant headache, irritability, unmotivated anxiety, fatigue, weakness, apathy.
Chorionic gonadotropin preparations
This substance is contained in the following medicines: Horagon, Profazi, Pregnil, Gonacor, chorionic gonadotropin.
Conclusion
Chorionic gonadotropin for which we have given instructions, use, indications, contraindications, action, side effects, analogs, composition, dosage, is prescribed when there is hypofunction of the genital gland of the pituitary and hypothalamus. Violations of the genital glands, most often, are determined during puberty. Therefore, adolescents must undergo regular medical examinations, during which specialists may suspect the presence of pathology and prescribe adequate treatment in time.
It is not necessary to wait for an ultrasound examination, a medical examination or a test result to find out about the long-awaited conception. The fastest and most accurate result will give a blood test for hCG, which is done after ovulation and shows how long the pregnancy is. This analysis determines the level of the hormone HCG in the blood of a woman, which is produced by the chorion - one of the fetal membranes of the embryo. Pregnancy tests work on the same principle, but their sensitivity is not so great, and besides, the result may be false-positive or false-negative. In this regard, a blood test will be much more accurate and will be able to determine pregnancy much faster than tests. Its value is large enough:
- If you donate blood for several days, with an interval of a day, then the increase in hCG can determine whether a pregnancy develops.
- Analysis will be able to pretty early terms say whether your pregnancy is multiple or multiple.
- According to the results of the study in the dynamics can determine whether the pregnancy is frozen or not.
- In addition, the observation of hCG over time will help determine whether gestational egg out of the uterus, or the pregnancy continues to progress. This is shown in cases where the pregnancy had to be terminated for medical reasons for a short period.
- The increase in hCG in non-pregnant and in men will indicate the possible development of various diseases, and this will allow such people to see a doctor as soon as possible.
Thus, the blood test for hCG is important not only during pregnancy or its planning, but also in other situations that require medical supervision.
When to take the HCG analysis
Despite the fact that the level of hCG in the blood is most quickly able to announce the presence of pregnancy, this does not mean that you can take it several hours after sexual intercourse during ovulation. The fact is that this hormone begins to be produced only when the implantation of the ovum to the wall of the uterus occurs (or to the wall of the fallopian tube, if the pregnancy is ectopic). Implantation does not occur in the first hours of conception. AT 
in most cases, it does not occur even in the first two or three days after fertilization of the egg. According to the observations, the implantation of the ovum may not occur earlier than 4 days after ovulation, and the main percentage is 5-6-7 days. In total, implantation can occur any day, starting at 4 and ending 12 days after ovulation.
If you keep a basal temperature chart, then there may be a characteristic drop in temperature during this period: it will drop by 0.3-0.4 degrees by one day. For example, it can fall from 37.4 to 37.0 degrees. This is called implant retraction, and it means that from now on, the embryo begins to produce the hormone hCG hormone, which can now be detected in the blood of its mother.
In this regard, many women are wondering: when to take a blood test for hCG? Experts recommend doing it no earlier than a week after the alleged ovulation. And it is desirable to donate blood more than once, but at least two, in order to make sure that the pregnancy is alive and progressing in its development. A little later, an indicator of an increase in hCG may be sensitive pregnancy tests: first, their test strip will be dim, but if you repeat the procedure with a test of the same brand after 48 hours, you will notice progress in coloring.
It is important to know some of the features of blood sampling for this analysis:
- HCG is given on an empty stomach, the break must be at least 5 hours, starting from the last meal;
- blood is taken for analysis from a vein;
- analysis for hCG should be taken no earlier than 7 days after the expected ovulation;
- it is advisable to donate blood in the morning when the interval between meals will be quite large.
Now you can receive test results for HCG via e-mail, just a few hours after the blood collection. This helps to act quickly, if the hormone is suddenly detected, and the woman, for example, has a lack of progesterone.
Hormone hCG and preparations containing progesterone
There is a category of women who have in the second phase of the cycle, they have to take special drugs that artificially increase the level of this hormone in the blood. As a rule, it is either Duphaston or Utrozhestan in various dosages that the doctor prescribes. In this regard, such women often wonder: how to take hCG, if you have to take hormonal drugs? Will they affect the result of the analysis?
To answer this question let us turn to what is progesterone. This is a hormone that the adrenal glands produce and which is indispensable during pregnancy: it helps it to hold on, to successfully implant and develop, bypassing the detachment and regression. In turn, we know that hCG is a hormone that is released not by the woman herself, but by the fetal egg. Thus, it is obvious that taking Duphaston or Utrogestan is not able to affect the blood test for HCG, causing the result to be false-positive.
However, these two hormones are related to each other, but only in the sense that progesterone helps the pregnancy to stay in the uterus and develop. Accordingly, the level of hCG is growing, because the future baby is alive. If there is no pregnancy, and progesterone is taken, then the result of the analysis will still be negative.
Growth of hCG in ectopic pregnancy
With an ectopic pregnancy, an increase in the level of hCG in the blood has a completely different dynamic. When uterine attachment of the ovum, the hormone doubles its amount in the woman's body every 48 hours. However, during pregnancy, located in the fallopian tube, the growth of hCG will not be so fast. If a woman watches the dynamics of several of her analyzes, she will notice that doubling the level of this hormone will occur not after 48 hours, but only after a few days. Of course, the final diagnosis can be made only by ultrasound and after an examination on a gynecological chair, but early observation of a blood test for hCG over time will determine ectopic pregnancy much earlier than it happens in normal cases. This will help remove the fertilized egg from the fallopian tube, avoiding tearing it and passing, thus, a direct threat to the life of the woman.
The rise and fall of hCG with frozen pregnancies
Freezing pregnancy only in rare cases gives a slight increase in hormone levels. Decoding the analysis in dynamics, usually, shows that immediately after the death of the embryo, this hormone begins to break down in the woman’s body. For some time, its amount may be unchanged and remain at the same level. Then hCG falls, which will finally indicate that the pregnancy has died.
In other cases, the level of chorionic gonadotropin begins to decrease immediately, on the first day after the termination of the vital activity of the ovum.
It is characteristic that, unlike ectopic, missed abortion may have absolutely no signs. A woman may not have bleeding and pain, even all signs of pregnancy (toxicosis, breast tenderness) may still persist. It so happens that she may not even know for two or three weeks that the pregnancy has died. It is in these cases that the observation of the dynamics of the blood test for hCG will be able to diagnose the condition of the embryo, and the weeks after the pregnancy, when deciphering the data, the embryo becomes clear or dead.
Chorionic gonadotropin
International title:
Dosage Form:
Pharmachologic effect:
Indications:
Gonacor
International title: Chorionic gonadotropin (Gonadotrophin chorionic)
Dosage Form: lyophilisate for solution for intramuscular injection
Pharmachologic effect: Hormonal drug secreted from the urine of pregnant women. It has luteinizing and follicle-stimulating effect. Stimulates synthesis ...
Indications: Hypofunction of the genital glands (due to impaired activity of the hypothalamus and pituitary gland). In women: dysmenorrhea, ovarian dysfunction, anovulatory ...
Pregnil
International title: Chorionic gonadotropin (Gonadotrophin chorionic)
Dosage Form: lyophilisate for solution for intramuscular injection
Pharmachologic effect: Hormonal drug secreted from the urine of pregnant women. It has luteinizing and follicle-stimulating effect. Stimulates synthesis ...
Indications: Hypofunction of the genital glands (due to impaired activity of the hypothalamus and pituitary gland). In women: dysmenorrhea, ovarian dysfunction, anovulatory ...
Profazi
International title: Chorionic gonadotropin (Gonadotrophin chorionic)
Dosage Form: lyophilisate for solution for intramuscular injection
Pharmachologic effect: Hormonal drug secreted from the urine of pregnant women. It has luteinizing and follicle-stimulating effect. Stimulates synthesis ...
Indications: Hypofunction of the genital glands (due to impaired activity of the hypothalamus and pituitary gland). In women: dysmenorrhea, ovarian dysfunction, anovulatory ...
Horagon
International title: Chorionic gonadotropin (Gonadotrophin chorionic)
Dosage Form: lyophilisate for solution for intramuscular injection
Pharmachologic effect: Hormonal drug secreted from the urine of pregnant women. It has luteinizing and follicle-stimulating effect. Stimulates synthesis ...
Indications: Hypofunction of the genital glands (due to impaired activity of the hypothalamus and pituitary gland). In women: dysmenorrhea, ovarian dysfunction, anovulatory ...