The most popular and in demand rapid pregnancy test is based on detecting the level of human chorionic gonadotropin in the urine. It is also found in the blood. And in this type of study, the hormone will help you find out more important and accurate information.

Human chorionic gonadotropin is stimulated by the gravid uterus. It is initially produced by chorionic villi, and then by the placenta itself.

Therefore, pregnancy is confirmed by early stages the appearance of a minimum concentration of the hormone in a woman’s blood. In urine, the level required for the reaction is reached much later.

Human chorionic gonadotropin begins to be produced immediately after fertilization of the egg by its special component, syncytiotrophoblast.

This is observed immediately after the fertilized egg “sticks” to the wall of the uterus and affects the development of the placenta, which subsequently plays a major role in the production. During oncological processes of the female reproductive system, the concentration of the hormone also increases due to the growth of trophoblasts.

The structure of hCG includes 2 structural particles - alpha and beta, each responsible for separate functions. The first alpha fraction is similar in structure and mechanism of action to thyrotropin and luteinizing hormone.

The second particle, beta, is a unique part of the hormone that is responsible for functional features connections.

Thus, a pregnant woman with an increased level of beta fraction of hCG is at risk of developing a child with Down or Edwards syndrome.

But the analysis cannot accurately confirm or refute the diagnosis; for this it is necessary to conduct a study of the amniotic fluid.

The level of this hCG fraction should be monitored during the period from 8 to 12 and from 15 to 20 weeks of pregnancy.

Indications for analysis

The main indication for a blood test is to confirm and monitor the progress of pregnancy. The free fraction of total human chorionic gonadotropin does not require special instructions and regulations.

But its constant monitoring is necessary in pregnant women with a history of the following pathological conditions:

• polyhydramnios;
• diabetes;
• early toxicosis;
• gestosis of various etiologies;
• taking progestational medications;
• suspected ectopic pregnancy;
• tubal obstruction;
• prolongation of pregnancy;
• salpingitis, adnexitis suffered;
• miscarriages.

But the hCG beta particle is controlled in conditions that increase the risk of developing fetal pathology:

• a history of pregnancies with Down or Edwards syndrome;
• genetic diseases in close relatives;
• congenital malformations in the mother or relatives;
• maternal exposure during pregnancy;
• age over 35 years.

Tests are also prescribed as a screening method at any stage of pregnancy. Used for newborns

Preparing and conducting analysis

The analysis is carried out by collecting the patient’s venous blood, which is drawn from peripheral veins into a special tube - Monovette.

This type of tube allows, using special needles and negative pressure inside, to draw blood directly into the container, eliminating the influence external factors on the result during the transfusion of biomaterial from a syringe into a special container.

The analysis is carried out without special preparation. But it is recommended to adhere to the basic rules:

• take on an empty stomach (8 hours after eating);
• the day before collection, follow a light carbohydrate diet;
• limit physical activity within 72 hours;
• avoid emotional stress;
• eliminate alcohol intake for a week;
• stop all medications taken if possible;
• about all procedures performed the day before, drug treatment inform your doctor in advance.

Usually, hCG levels are determined in combination with other hormones, which can give a more detailed overall picture.

The level of the hormone in urine and blood can only be affected by those hormonal drugs, which mainly contain molecules of human chorionic gonadotropin. They are usually used to support and maintain pregnancy in women with a history of risk factors.

When taking a pregnancy test for the first time, the recommended period is 4-5 days of missed menstruation.

Since the hormone will begin to be produced after the fertilized egg “sticks” to. In any case: positive or negative reactions, repeated confirmation is required after a few days.

Other dates for monitoring the normal course of pregnancy in all trimesters are prescribed by the attending physician individually for each patient.

The analysis can be done in any laboratory. Results when using rapid tests are ready within 1 hour after blood collection. But carrying out qualitative and quantitative reactions using special reagents can take from 1 to 3 working days.

Compounds for detecting hCG levels are quite expensive, so some hospitals and laboratories cannot afford it. The result may be further delayed due to the analysis being sent and interpreted by another laboratory.

Analysis transcript

Each period of pregnancy has its own norms for the level of human chorionic gonadotropin. The laboratory provides its normal indicators, which depend on the research method, the use of the amount and type of reagents.

But the average values ​​are always approximately the same. It is better to entrust the interpretation of the analysis to a specialist, since the individual characteristics of the patient should be taken into account.

In a healthy non-pregnant woman of reproductive age permissible level HCG should not exceed 5 mU/ml.

In case of pregnancy, the results must be checked with special tables, since hCG norms change for this group of patients weekly.

• 1 week of pregnancy - 20-150 mU/ml.
• The end of 2 - beginning of 3 weeks is characterized by an increase in hCG levels from 100 to 4870 mU/ml.
• The 4th week of pregnancy ends with an increase in hormone production to 2500-82000 mU/ml.
• The 5th week of pregnancy can increase the hormonal level of hCG to 151,000 mU/ml.
• At the 6th week of pregnancy, the indicator continues to gain momentum and increase the concentration of the hormone in the blood, but it is already slowing down and amounts to 233,000 mU/ml.
• During 7-10 weeks of pregnancy, hCG in the free fraction remains mostly stable and has a fairly large range of norms: 20900 - 291000 mU/ml.
• From weeks 10 to 16, hormone levels begin to fall, but at a slower pace relative to their previous increase. Indicators range from 6150 to 103,000 mU/ml.
• By week 20, the levels decrease even more and now amount to 4730 - 80,000 mU/ml.
• The remaining half of the baby's pregnancy is characterized by a relatively constant level, which is explained by the weakening of the protection of the pregnant uterus and the establishment of constant homeostasis in the body, necessary for the normal development of the fetus. The hCG level in the second half of the second and throughout the third trimester is 2700 - 78000 mU/ml.

It is worth remembering that the results should only be interpreted by a specialist.

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One of the most accurate methods for determining pregnancy in the early stages is a blood test for the amount of hCG hormone. Human chorionic gonadotropin beta particle is a unique glycoprotein unit that is produced after the embryo attaches to the uterus. Its blood levels vary depending on the duration of pregnancy and play an important role in the synthesis of the hormones estradiol, progesterone and estriol. For those interested in their “interesting” situation, it will not be difficult to accurately determine the presence of pregnancy by donating blood for hCG. What is this, how the procedure works, when to undergo it and how to evaluate the results, we will consider in the article.

What is hCG?

Human chorionic gonadotropin is a hormone with a protein structure. It is produced by the tissues of the developing embryo throughout the entire gestation period. Thanks to this substance, ovarian function is inhibited. New eggs stop maturing, and the next menstruation does not occur. hCG adjusts female body on pregnancy, promoting hormonal changes.

This glycoprotein consists of two units: the alpha unit is similar to other hormones in the body, while the beta unit is unique. Therefore, when carrying out the analysis, they focus specifically on the concentration of the beta particle.

A small presence of the hormone in the human body is considered normal even in the absence of pregnancy. It is produced by the pituitary gland. Sometimes some amount of the hormone is found in the body of men and non-pregnant women. The normal level of hCG in the blood is up to 5 mIU/ml, and for women during menopause - up to 9.5 mIU/ml.

How to determine pregnancy using a blood test?

The level in a woman’s body has become a universal indicator of pregnancy. Express strips are designed exactly according to this principle. They respond to the level of the hormone in the urine, which begins to increase noticeably within 2 weeks after fertilization. However, tests are not always accurate, and they cannot accurately determine the gestational age. Therefore, women who expect to conceive are advised to donate blood for hCG. What is this? A routine procedure performed in any private or public laboratory.

The results obtained are highly accurate. Many women are interested in the question: “When will blood test for hCG show pregnancy?” Obstetricians-gynecologists recommend taking your time and thinking about conducting an analysis only after a delay. The minimum period after which it is possible to determine pregnancy is 7 days from the moment of conception.

When can you donate blood for hCG?

Despite the fact that a blood test is a highly accurate and accessible method for finding out about pregnancy, it is worth thinking about the timing of its implementation. Of course, nothing prevents you from contacting a diagnostic laboratory within a couple of days after conception. But the results of such an analysis will not be reliable. And yet, when can you donate blood for hCG to get accurate data about pregnancy? Doctors recommend the following terms:

• If a woman knows exactly the day of conception, then 2 weeks need to be counted from it. On the received date and schedule the analysis;
• in cases where it is impossible to determine the moment of conception, it is considered advisable to take the test 3 weeks after the date of missed menstruation.

To obtain reliable results, you should be patient and wait the recommended period.

How to get tested and how much does it cost?

Women inexperienced in matters of pregnancy and motherhood ask many questions about the analysis. How to take hCG, what rules must be followed? In fact, everything is much simpler than it seems. Blood for hCG is taken from the cubital vein in an amount of 5 ml. It is advisable to come for the test in the morning and not eat anything before the procedure. Before receiving a doctor's referral, it is better to warn about the appointment medicines. This may affect the results of the study.

What is the cost of a blood test for hCG? Price may vary depending on laboratory. On average, the service will cost 500 rubles, in the capital - about 800 rubles. This applies to private clinics and diagnostic centers. IN budgetary institution Referrals are issued free of charge at your place of residence.

Interpretation of primary results

Having decided when it is better to donate blood for hCG, having gone through the procedure and received the desired result, I would like to learn more about what the numbers on the test report mean. There are three possible scenarios:

1. Negative - the hormone is determined in the amount of 0 to 5 mIU/ml.
2. Doubtful - chorion indicators are recorded in the range of 5-25 mIU/ml.
3. Positive - hCG in the blood exceeds 25 mIU/ml.

If a questionable result is obtained (a slight increase in the hormone), it is recommended to repeat the analysis in a few days. In this case, it is advisable to observe the same conditions for collecting and diagnosing blood: appear at the same clinic, at the same time of day and on an empty stomach. The new result is compared with the previous one. If the deviation in one direction or another persists and exceeds 50% of the norm, a conclusion is drawn about the presence of a pathological process (a sign of tumors). In the case of a 20% deviation from the established values, the result is again called into question by ordering a new study. In some cases, if the results are stable and there are no pathologies, a conclusion is made about the individual level of chorionic hormone in the blood.

A one-time analysis is performed only if a negative result is obtained, and there is no doubt about it over time. When pregnancy is confirmed, it is necessary to periodically monitor the hCG hormone in the blood.

Changes in test results by week of pregnancy

In the first weeks of pregnancy, the level of chorion hormone in the blood increases significantly. The growth rate is considered in days required to double it:

• up to 6 weeks - 2;
• 6-8 weeks - 3;
• 8-10 weeks - 4.

By the 11th week of pregnancy, the result of a blood test for hCG will show the maximum value. After which a gradual decline will begin. At 16 weeks, the indicator will be identical to a 7-week pregnancy. During the remaining period of gestation, the hormone level will remain stable.

The variation in chorionic hormone levels is very high: all options in the specified range are considered normal. In addition, only a doctor can reliably interpret the results. Sometimes the individual hormone level in the blood is slightly higher or lower than the standard.

HCG indicators during IVF

If a woman has undergone IVF, the procedure for conducting the analysis will change slightly. When will the blood test for hCG show pregnancy in this case? The answer from experts is this: the procedure should be completed no earlier than 12 days after the injection containing the chorionic hormone. The table shows the average hCG values ​​in the blood after implantation of the embryo into the uterine cavity.

How to take hCG if injections containing it were prescribed after implantation of the embryo in order to maintain the functioning of the corpus luteum? You should wait a few days before taking the test. Otherwise, the results will be overestimated.

High levels of hCG in the blood

Most pregnant women have little or no knowledge of their pregnancy. If everything is fine, the doctor rarely tells the expectant mother about the results of each examination. It's another matter when problems arise. HCG in the blood may be higher or lower than normal. And only with rare exceptions does this not indicate a pathology of fetal development or maternal health.

What do the inflated numbers in the hCG test results hide? Sometimes it’s nothing serious: incorrect timing or multiple pregnancies. However, suspicion often falls on the presence of a woman diabetes mellitus, toxicosis or pathologies in embryo development. If an elevated level of hCG is detected in the blood, a repeat test and additional examination of the expectant mother are prescribed.

Low hCG levels

The level of the chorion hormone in a woman’s blood makes it possible to accurately not only detect pregnancy in the early stages, but also monitor the development of the embryo throughout the entire period of gestation. HCG is a specific hormone of motherhood. Its underestimated indicators, as a rule, indicate problems with the course of pregnancy:

• threat of miscarriage;
• delay in embryo development;
• fetal death;
• “freezing” of the embryo;
• ectopic pregnancy;
• pathology of the placenta or fetus.

Any deviation from the norm in the results of the hCG analysis is an alarming sign that requires immediate consultation with a doctor for advice.

Should you rely on the results of the analysis?

And yet, blood test for hCG - what is it? How much can you trust a typical laboratory test? This procedure is similar to sampling because hCG is one of them. The reliability of the result is at a high level: inaccuracies are rare, usually due to the reception medicines or consumption of specific foods on the eve of analysis.

Laboratory tests may give a false positive or false negative answer. In the first case it will be determined high level HCG, typical for a pregnant woman. Only after a while does it become clear that there is no embryo in the uterine cavity. Why is this happening? There are few options: either the drugs taken by the woman (including those containing hCG) are to blame, or this is a serious sign of pathology.

A false negative result usually occurs when the test is performed too early. There are also anomalies in the development of the embryo in the early stages. In any case, a repeat analysis and ultrasound are prescribed.

conclusions

Blood test for hCG - what is it? It turns out to be a standard and very informative analysis. With its help, you can accurately diagnose pregnancy after just 2 hCG - a specific hormone produced by the tissues of the chorion (later the placenta). After entering the uterine cavity, its quantity increases sharply, stimulating the restructuring of the body for bearing the fetus. HCG indicators characterize pregnancy in the best possible way and notify in time expectant mother not only about the “interesting” situation, but also about disruptions in the baby’s development.

Dynamics of pregnancy development according to the results of hCG tests.

• Our medicine obliges patients to undergo a lot of different tests to determine their state of health or ill health.
• Several decades ago, we were surprised by the ability of doctors to immediately talk about the absence/presence of pathologies or diseases
• Now, with the development of Internet resources, access to the study of material related to the appointment and interpretation of various tests and analyzes is open
• We can familiarize ourselves with it in detail or superficially and ask questions to the doctors. Although they really don’t like the last moment, and sometimes it’s annoying

What is hCG? When to take the test?

Human chorionic gonadotropin, or hCG for short, is a specific hormone that is produced in the body in the presence of pathological growth of cells of the reproductive system.

Its most common use is to determine the fact and duration of pregnancy. Women also take a test for the amount of hCG:

• to understand how the baby develops in the womb
• if a tumor is suspected
• to assess the quality of induced abortion
• if there is a threat of miscarriage

Men are prescribed a test to determine the absence/presence of testicular tumors.

HCG consists of 2 elements:

• alpha particles
• beta particles

Based on the amount of beta-hCG in the blood in laboratory conditions, the presence of pregnancy or, conversely, its absence is determined.

When a woman is in an interesting position, the chorion, the membrane of the fetus, is responsible for the production of hCG. It regulates the growth and development of the unborn baby in the mother’s body until the placenta is formed, which will take over these functions.

Human chorionic gonadotropin also regulates the hormonal levels of a pregnant woman. It controls and stimulates:

• production of the hormones progesterone and estrogen
• work of the corpus luteum in the ovaries
• normal development of the baby in the womb in the first trimester

Nausea, which plagues many women early in pregnancy, occurs due to an increase in the concentration of hCG in the body.

Human chorionic gonadotropin is already detected in the blood through:

• week after fertilization
• a couple of days after a missed period

It appears in urine a couple of days later.

It is worth noting that all pharmacy pregnancy tests show an increased concentration of hCG or the absence thereof.

Blood test for hCG - interpretation: table

• If you are prescribed a blood test for hCG, do it in the morning on an empty stomach.
• The unit of change in hCG levels is mIU/ml - milliinternational unit per milliliter. In the body of a non-pregnant woman, the level of human chorionic gonadotropin ranges from 0 to 5 mIU/ml
• From the moment the fertilized egg attaches to the wall of the uterus, the female body begins increased production of human chorionic gonadotropin. On average, its quantity doubles every day or three.
• This trend continues until 9-11 weeks of pregnancy. Then the indicator decreases and is fixed at a specific level

Approximately the dynamics of changes in the amount of hCG in the body of a pregnant woman looks like this:

HCG norms by week. Table

Let us note that the functioning of each individual woman’s body is very individual, so check the results obtained with the specialist who is observing you.

HCG norm by days from conception

• Each laboratory has its own standards and norms for interpreting tests, including hCG in the blood
• On the other hand, due to the difference in calculating the gestational age, differences in the results of the concentration of human chorionic gonadotropin are also possible
• The obstetric period is always longer than the embryonic period, since it is counted from the first day of the last menstruation

HCG norm by day from conception. Table

How does hCG rise during pregnancy?

• Human chorionic gonadotropin protects the embryo from attacks by the mother's body. In the first days and weeks, the latter perceives the former as foreign body and tries to get rid of him, push him out of himself
• Therefore, hCG affects areas of the brain that inhibit the functioning of the pregnant woman’s immune system. At the same time, this hormone takes control of the production of those substances that the embryo needs for successful development and life.
• Such a responsible mission of hCG is accompanied by its doubling every one and a half to two days, 5-7 days after conception. The doubling dynamics persists until 10-11 weeks of pregnancy. Afterwards the rate decreases to a certain point and remains until the end of pregnancy

From the tables above, it is clearly seen in numerical values changes in the concentration of human chorionic gonadotropin.

HCG during frozen pregnancy

• Fading of pregnancy most often occurs in the first trimester, rarely in later stages
• Due to the fact that the fertilized egg remains attached to the wall of the uterus for some time, hCG is produced. Its concentration increases slightly until the embryo detaches and exits

HCG for ectopic pregnancy

• The membrane of the embryo during an ectopic pregnancy produces the hormone gonadotropin in significantly smaller quantities than in a normal location in the uterus
• You won’t see doubling dynamics every 2-3 days. However, the increase in hCG levels persists, only at a much slower pace
• Sometimes it happens that an increase in the concentration of human chorionic gonadotropin has a negative tendency. That is, instead of an increase, there is a clear slight decline

HCG by day for twins

• Do you hold the hCG test results in your hands and see that the readings fluctuate around 5 mIU/ml? This means that pregnancy has not yet occurred or you were in a hurry to conduct research
• If you compare the dynamics of changes in human chorionic gonadotropin with a table of its growth and see that for a particular week your data is twice as large, there is a high probability multiple pregnancy
• Thanks to hCG data, you can be diagnosed with double pregnancy much earlier than ultrasound analysis
• For approximate figures for changes in the amount of hCG in the blood during multiple pregnancy, see the table below. The starting point is the first day of the last menstruation

HCG after IVF

If during a natural pregnancy it is enough to undergo several tests for the level of hCG, then after IVF regular monitoring of the concentration of human chorionic gonadotropin is the key to the success of the procedure and good development pregnancy.

To carry out IVF, doctors use embryos:

• three-day
• five-day

1. Therefore, the amount of hCG in a pregnant woman’s body is slightly different. For example, after transferring a three-day embryo, the pregnancy hormone has slightly higher values ​​than a five-day
2. You can easily find tables of norms and ranges of hCG values ​​after embryo transfer using the IVF method on the Internet, as well as from the doctor who performed this procedure
3. If you have successfully completed the IVF procedure, be prepared for the first two weeks to constantly monitor your condition. As soon as your human chorionic gonadotropin level reaches 100 mIU/ml, you can be congratulated on your pregnancy

Video: blood test for hCG

In order to diagnose pregnancy at an early stage, you can take a blood test for hCG. This method is considered one of the most accurate. Human chorionic gonadotropin is a hormone that begins to be produced in a woman’s body immediately after the implantation of a fertilized egg into the wall of the uterus.

Diagnosis of an increase in the level of hCG in biological fluids allows us to talk about pregnancy. IN in rare cases Hormone levels may also increase for other reasons. This is a sign of serious disturbances in the functioning of the body and requires immediate medical diagnosis and subsequent treatment.

First of all, human chorionic gonadotropin can be determined in the blood. Within a few days after conception, the concentration of the hormone in this biological fluid begins to increase.

Implantation of the embryo into the wall of the uterus occurs within a few days after conception. Thus, a blood test for hCG can be carried out already 5-7 days after intimacy. If pregnancy has occurred, the analysis will definitely show this.

You can donate blood for hCG at antenatal clinic, family planning center or in a special laboratory. The result of the analysis will be known very soon. It should be noted that this type of diagnostics is paid. A free test can be done only if you have a referral from a gynecologist.

Diagnosis of pregnancy at home

The level of human chorionic gonadotropin in the urine after successful fertilization increases at a much slower rate than in the blood. In order for pregnancy to be diagnosed using test strips, which are sold in every pharmacy, it is necessary to carry out the analysis no earlier than 2 weeks after sexual contact.

Considering that ovulation usually occurs in the middle of the cycle, pregnancy can be diagnosed using a standard test from the first day of missed menstruation.

The test can be done earlier. In many cases, pregnancy can be determined within 7-10 days after conception. It is worth remembering that in this case the probability of receiving a false negative result too big. If only one line appears on the test, you need to wait for the start of your missed period and do the express test again.

The level of hCG in body fluids will increase daily. If a woman doubts a negative test result, she can repeat it every 2-3 days.

Tip 2: How should hCG rise in early pregnancy?

Human chorionic gonadotropin begins to be produced in a woman’s body immediately after the implantation of a fertilized egg into the wall of the uterus. During the first half of pregnancy, the concentration of this hormone in the blood constantly increases.

Instructions

Human chorionic gonadotropin is a hormone that begins to be produced in a woman’s body during pregnancy. Before its onset, the concentration of hCG in the blood is only 0-15 mU/ml. Immediately after implantation of a fertilized egg, the hormone content in biological fluids begins to increase rapidly.

Standard pregnancy tests in the form of strips, which must be dipped into urine, can only be used from the first day of a missed period, but not earlier. If you do the test earlier, there is a high chance of getting a false negative result.

There is a certain schedule for increasing the level of hCG in the blood within normal limits. It is believed that every week the concentration of gonadotropin should increase by approximately 2-3 times compared to its previous value. But this is only an approximate growth rate.

On days 10-12 of pregnancy, the level of hCG in the blood is 100-150 mU/ml. Exactly in a week this value will increase to 200-400 mU/ml. At the 4th pregnancy, the concentration of the hormone in the blood should already be 2560 - 82300 mU/ml.

If the rate of increase in the concentration of hCG in biological fluids does not correspond to the norm, this may indicate the presence of a certain type of pathology. For example, a slow increase in the level of hormone in the blood may be a sign of an ectopic pregnancy, as well as an existing threat of miscarriage. A decrease in the concentration of hCG in biological fluids during the first trimester of pregnancy may indicate intrauterine fetal death.

note

Blood can be donated to determine the level of hCG at the antenatal clinic. In most clinics it is paid.

Helpful advice

Women who have already had the sad experience of miscarriage need to regularly donate blood to determine the concentration of hCG. This will allow us to identify some types of pathologies at the most early stages their development.

By progressive hCG we mean the concentration of human chorionic gonadotropin in the blood or urine, which is constantly increasing. This may indicate a normal pregnancy.

Progressive hCG and pregnancy

Human chorionic gonadotropin is a hormone that is synthesized in the human body under certain conditions. It is also called the pregnancy hormone, since it is after successful fertilization and implantation of the embryo into the uterine wall that the concentration of hCG in biological fluids increases.

Increased level the hormone may be observed in a number of cases, but in this case hCG will not be progressive. Its level will remain virtually unchanged or even decrease.

There are special tables that reflect the growth rates of the concentration of human chorionic gonadotropin in the blood during the first half of pregnancy. For example, in women, the hCG level should not exceed 2.5-5 mU/ml. Already a week after implantation of the embryo into the uterine wall, a sharp increase occurs. given value. The concentration of the hormone in the blood at the 2nd week of pregnancy should be 100-350 mU/ml. At 3 weeks of pregnancy, this value should already be 1100-2500 mU/ml.

Progressive hCG indicates a normal pregnancy. However, its growth should be observed only until the middle of the second trimester. Then, for several weeks, the concentration of human chorionic gonadotropin will remain unchanged, and then completely decline.

In what cases does the hCG level not increase?

If the cause of increased levels of human chorionic gonadotropin in the blood and urine is not pregnancy, then most likely its concentration will not increase over time. A positive hCG test is possible if the woman had an abortion shortly before donating blood or if she is taking hormonal medications.

Sometimes an increased level of the hormone in the blood may indicate the development of a benign or malignant tumor in the body. If a person takes tests again after some time, the hormone level in both cases will remain practically unchanged or increase slightly.

If a woman, but at the same time in the early stages, the concentration of hCG in her blood is not progressive, then this is a very alarming signal. The cessation of hormone production may be an indicator of an ectopic or frozen pregnancy. Sometimes this is a kind of warning about the possibility of its spontaneous interruption. That is why women at risk have a blood test for hCG almost every week.

Planning a pregnancy is a special period in a woman’s life, which does not always proceed joyfully and smoothly. Sometimes the two treasured stripes do not appear for a long time. Life turns into endless waiting.

The most patient wait for a delay in menstruation, and then another week later they conduct a regular test that reacts to the level of hCG in the urine. Those who can’t stand it do an analysis for the hCG content in the blood serum. It contains a higher concentration of the hormone.

An analysis for hCG in the blood makes it possible to diagnose pregnancy 7-10 days after the embryo attaches to the uterus. The method is considered highly accurate, its reliability is 99-100%. Can hCG not show pregnancy in the early stages, be false negative or false positive? Yes, sometimes this is possible. Read on to learn about the reasons for the erroneous result.

When are errors possible in hCG analysis?

To answer the question in more detail whether the hCG analysis can be erroneous, you should start from the specific situation. The level of human chorionic gonadotropin in the blood can change under the influence of drugs, due to the development of tumors, for physiological reasons. An error by the laboratory itself, poor-quality sampling of material, confusion with results, or problems with reagents cannot be ruled out.

It's important to understand that hCG analysis is as informative as possible during a comprehensive examination. You cannot draw a conclusion based on the concentration of the hormone in the blood alone.

What is hCG?

HCG is an acronym that stands for human chorionic gonadotropin. It is a hormone primarily used to diagnose pregnancy. HCG begins to be produced by the chorion (the embryonic part of the placenta) 6-8 days after fertilization of the egg. With normal fetal development, in just 7-11 weeks the level of the hormone increases to thousands of values.

What is human chorionic gonadotropin used for?

• helps a woman’s body adapt to pregnancy. Thanks to the secretion of glucocorticoids, as well as physiological immunosuppression, the development of a semi-foreign genetic organism within the uterus becomes possible;
• maintains the functional activity of the corpus luteum until the placenta matures (10-12 weeks). Thanks to hCG, the body produces enough exact amount the hormone progesterone, which plays vital role in maintaining pregnancy;
• supports the development and functioning of the placenta, improves trophism and promotes the quantitative growth of chorionic villi (chorionic cells that grow into the uterine mucosa and participate in the formation of the placenta);
• taking hCG drugs is used to solve the problem of infertility in women, to prevent miscarriage in the first trimester. IN male body the hormone stimulates the production of sex hormones and spermatogenesis.

HCG is not produced in the body of healthy men and non-pregnant women. Otherwise, an increase in hormone levels may indicate the development of a malignant tumor.

Why do you need to get tested for hCG?

Measuring the level of hCG in the body allows you to establish pregnancy and identify abnormalities in its development. Less commonly, it is used to exclude malignant processes (oncological diseases).

The most affordable way to measure hCG is to take a regular pharmacy pregnancy test. They come in several types (strips, inkjet, electronic), and react only to the hormone content in the urine. At the required concentration of hCG, the second strip turns red. Urine reacts with a special chemical, with which the test is processed. They have different sensitivity, on average, they respond to a hCG concentration of 20–25 mIU/ml and give accurate results starting from the eighth day of missed menstruation.

A blood test for the content of human chorionic gonadotropin allows not only to determine pregnancy in the early stages, but also to determine the exact amount of the hormone. The analysis is more informative and reliable. The volume of hCG required for diagnosis in the blood serum appears earlier than in the urine. Already on the first day of implantation, the hCG level can reach 2-10 mU/ml; within 7 days the value increases to 22-105 mU/ml.

Rules for taking the analysis

Laboratory testing to determine early pregnancy is recommended after a 3-5 day delay in menstruation. Otherwise, the result may be false negative. HCG levels increase differently in women. In addition, it is not always known when implantation occurred. With late ovulation, the result on the first day of the delay may be questionable. Very often the analysis is done not once, but several times to observe dynamics.

What rules apply when conducting a laboratory test:

• You need to take the test in the morning on an empty stomach. If a different time is chosen, food intake stops 4-6 hours before;
• the doctor must be notified about taking medications;
• to establish the fact of pregnancy, hCG analysis is carried out in combination with an ultrasound intravaginal sensor;
• if a questionable result is obtained, the analysis is repeated after 2-3 days;
• To diagnose fetal pathologies, a study of hCG levels is carried out at 14-18 weeks of pregnancy.

A gynecologist usually talks about the rules for preparing for an hCG analysis. The doctor may make individual recommendations, such as stopping certain medications or other recommendations, based on the patient's medical history (the totality of information obtained during a medical examination).

Norms of hCG in the blood of pregnant women

Material for research is collected from a vein. The level of hCG during early pregnancy increases daily until 7-11 weeks. Then the concentration of the hormone in the blood gradually decreases. The standards that doctors are guided by are given in the table:

In men and non-pregnant women, hCG levels are 0-5 mU/ml.

It should be taken into account that laboratories use different reagents and therefore the standards may differ from the statistical average. You should rely on the values ​​indicated on the sheet with the analysis result. Usually the normal limits are indicated in the extreme column on the right or below.

Standards for implantation days

Due to the fact that the obstetric gestational age (based on the date of the last menstruation) often differs from the actual one, it is more correct to focus on another table. However, it only works if the woman knows exactly on what day the fertilized egg was implanted into the uterine wall. Many feel this moment quite clearly - a pain appears in the lower abdomen, and a few drops of blood are found in the vaginal discharge.

When making calculations, it should be taken into account that the day of implantation does not coincide with ovulation. After fertilization, the egg migrates into the uterine cavity and attaches to it approximately on days 3–12 (usually 8–10).

Norms for in vitro fertilization (IVF)

HCG levels after IVF double every 36-72 hours. To determine the norm, both standard tables and special ones are used, taking into account the age of the embryo and the day of its transfer.

The first test for hCG levels is carried out on the 14th day after IVF. A value of 100 mU/ml is regarded as pregnancy. A reading below 25 mU/ml indicates that conception has not occurred.

Deviations hCG from normal

If the concentration of hCG does not correspond to the values ​​​​in the table, the woman is prescribed additional examinations and tests. There are deviations from the norm, both smaller and larger. hCG negative, as well as an indicator of 0-5 mU/ml excludes pregnancy.

Low hormone levels may mean:

• the gestational age is calculated incorrectly;
• fetal development has stopped, frozen pregnancy;
• ectopic pregnancy;
• risk of miscarriage;
• chronic placental insufficiency;
• changes in hormonal levels and the rate of hCG synthesis;
• death of one fetus when carrying twins;
• post-term pregnancy.

Too high a hCG level may be a sign of:

• multiple pregnancy;
• toxicosis;
• gestational diabetes mellitus;
• tumors in a pregnant woman;
• developmental defects of the baby;
• chromosomal abnormalities in the fetus;
• taking gestagens.

Can a blood test for hCG be wrong? This rarely happens. The accuracy of the laboratory test is 99-100%. But we must not forget about the human factor. People work in laboratories who can simply confuse collected material. If the prognosis is unfavorable, it is better to retake the test again.

False positive result

This includes the situation when there is no pregnancy, and the hormone level exceeds 5 mU/ml. Reasons why the test is positive:

• HCG can be produced in the body during hydatidiform mole, when after conception the embryo does not develop normally, and the chorionic villi grow in the form of bubbles (from 1 case in 100 pregnancies to 1 in 5000). In 15-20% of cases it transforms into a malignant tumor;
• taking human chorionic gonadotropin drugs. Used to treat infertility, restore the menstrual cycle;
• postmenopause. For physiological reasons, the level of hCG after menopause can reach 14 - 15 IU/l. There are often cases when, when passing a pharmacy test (sensitivity 10 IU/l), women appear 2 stripes, although there is no pregnancy and cannot be;
• diseases: ulcerative formation of the stomach and duodenum, inflammation of the gastrointestinal tract, some liver diseases, tumors internal organs, cancer of the lungs, stomach or pancreas. At a level of 1000 mU/ml, the prognosis for the patient is positive;

Other reasons for increased hCG besides pregnancy:

• biochemical pregnancy;
• recent abortion;
• miscarriage.

Sometimes a sperm successfully fertilizes an egg and the fertilized egg even manages to attach to the walls of the uterus, but the time for menstruation comes and the pregnancy is terminated. In this case, a woman may not feel its signs, not pay attention to heavier menstrual flow, or a slight delay. It turns out that there is no longer pregnancy, but the hCG level is increased. After an abortion or miscarriage, the concentration of the hormone decreases within 4-6 weeks.

Also, the possibility of pregnancy cannot be completely ruled out. A laboratory hCG test can show interesting situation at the earliest stages, when neither test strips nor some ultrasound machines can confirm it.

False negative result

Can hCG be negative during pregnancy? Yes maybe. This is especially often observed when using test strips and early diagnosis even before the delay (90% of cases). Possible reasons false result:

• analysis carried out too early;
• late ovulation on days 18-26 of the menstrual cycle;
• late implantation of the embryo on days 11-12 from conception;
• individual characteristics of the rate of hCG production;
• conducting a home pregnancy test when drinking a lot (the concentration of the hormone in the urine decreases), a defective test.

If the hCG is negative before the delay or a few days after it, there is no need to worry. The best solution is to observe the hormone concentration over time. If conception has occurred, then after a few days the indicators will increase several times.

List of drugs that can affect hCG levels

Can the hCG test be erroneous when taking medications? Yes maybe. List of drugs that increase the concentration of the hormone in the blood (containing human chorionic gonadotropin):

• Decayed;
• Horagon;
• Gonakor;
• Profasi;
• Chorionic gonadotropin.

List of drugs that reduce the concentration of the hormone in the urine (diuretics):

• Diacarb;
• Furosemide;
• Veroshpiron;
• others, including herbal preparations.

As for taking gestagens ( Duphaston, Progesterone, Utrozhestan), doctors have not identified a direct effect on human chorionic gonadotropin. These drugs cannot cause false hCG levels during early pregnancy. Also, diet, unbalanced nutrition, smoking, and alcohol do not affect the hormone content.

How long can a test not show pregnancy?

Many women force things and rush to check hCG even before the delay. But the result often does not bring peace of mind, but makes you worry even more. In order not to worry about a possible error in the end, you should adhere to the deadlines specified by doctors and conduct testing 3-5 days after the delay. In case of irregular menstruation, it is recommended to take the test 12-15 days after ovulation.

So, can the hCG blood test be wrong? The reliability of a laboratory test depends on many factors, ranging from: proper preparation women to collect material, ending with the potential of the selected laboratory, the level of qualifications of the laboratory assistant and doctor. In addition, the patient’s medical history is important: whether she is taking medications, whether she had a recent miscarriage, when ovulation occurred, and much more. You should contact your doctor and correctly interpret the test result, repeat it if necessary, and undergo additional tests.