Human) is currently one of the most reliable methods for diagnosing and determining pregnancy. This hormone is produced by the embryonic membrane throughout the entire period of gestation, and its concentration level varies depending on the period. The highest numbers are observed at 10-12 weeks.
When a woman receives a referral for this study, the question most often arises about how to donate blood for hCG. After all, this is one of the most exciting moments, so you want to prepare for it as expected. Indeed, such diagnostics require special conditions that significantly increase the reliability of the results. The basic rule that every woman going to the laboratory should remember is that blood is donated for hCG on an empty stomach and nothing more! Why is this so important? The fact is that hormones are subject to absolutely any factor from the outside, as a result of which the resulting numbers can change in one direction or another. Accordingly, such an analysis cannot be considered reliable, and the consequences may lead to an incorrect diagnosis. That is why every pregnant woman needs to approach this issue with full responsibility and find out from the doctor all the details about how to donate blood for hCG.
What else does human chorionic gonadotropin say?
Determining the level of this indicator can provide information about some other circumstances regarding the unborn child, namely:
- Presence of an ectopic pregnancy.
- Lack of placental nutrition.
- Presence of risks contributing to miscarriage.
- Post-term pregnancy.
- The presence of defects in the fetus.
In addition, excessively elevated levels may indicate toxicosis, diabetes, multiple pregnancies and late gestosis. These circumstances once again emphasize that you definitely need to know how to donate blood for hCG.
How is a regular pregnancy test different?
Oddly enough, urine testing is carried out to determine the same indicator, i.e. hCG, but their effectiveness is not as high as in blood. They can show more accurate results in later stages of pregnancy. This is due to the fact that the concentration of hormones in the blood is several times higher than in the urine.
Possible mistakes
Even if you have learned how to donate blood for hCG and done everything correctly, sometimes errors still occur. Most often this happens when a woman does not wait until her menstruation is delayed. It is ideal to conduct such a study on the 10-12th day from the moment of conception.
If the blood test for hCG is negative?
Sometimes, with obvious signs of pregnancy, the analysis shows a low level of the indicator, which may indicate an ectopic location of the embryo. If the results suddenly begin to show negative results after high numbers, then you can suspect an incipient miscarriage or fetal death. In both cases, immediate hospitalization of the woman in a hospital is required.
Almost everyone is well acquainted with a pregnancy test - some from hearsay, while others have had to use it more than once. But not many people know about a method that allows you to confirm an “interesting position” several days earlier than the notorious two stripes. This opportunity is provided by donating blood for hCG - human chorionic gonadotropin, produced in the female body during conception.
What is hCG and its role in the body?
Human chorionic gonadotropin is a biologically active substance (BAS) produced by one of the components of the egg after fertilization. This hormone is first produced by the membrane of the embryo - the chorion, which stimulates the development of the placenta. After the baby's place has formed, the syncytio-trophoblast of the placenta is responsible for its production. It should be noted that this hormone increases noticeably in the blood after the fertilized egg attaches to the wall of the uterus - approximately 6–8 days from conception.
The described substance is of no small importance for diagnosing oncological processes in both women and men, which often makes a blood test for hCG one of the first doctor’s orders. Until now, scientists cannot come to a clear conclusion - changes in hormone levels are the cause or consequence of cancer development. This became the reason for banning the over-the-counter sale of dietary and homeopathic medications containing hCG.
In its structure, human chorionic gonadotropin is a glycoprotein consisting of 237 amino acids. Its basis is 2 subunits – “α” and “β”, which are considered the most important characteristic of the substance. Thus, the α-component is identical to similar components of a significant number of other biologically active substances. But for diagnostics, β is considered a unique element. Its level underlies the determination and monitoring of the course of pregnancy, as well as the identification of a certain number of pathologies.
And it is the β subunit that will show pregnancy in the blood serum approximately a week after conception. But at the end of gestation and delivery, this hormone should not normally be detected either in the woman’s blood or in the urine. The same applies to artificial termination of pregnancy - if after several days this hCG component is detected, then this is a signal of poor-quality surgical manipulation.
For a person, and in particular a woman, chorionic hormone performs the following list of functions:
- Stimulation of the synthesis of glucocorticoid hormones, which ensure adaptation of the body during pregnancy, which is defined as chronic stress for the immune system.
- During the first 6 gestational weeks, sufficient production of hCG is the key to the normal functioning of the corpus luteum. The latter takes an active part in the synthesis of progesterone and estrogen - the most important components for the body of a pregnant woman.
- Directly ensuring adequate performance of the child's place, that is, a satisfactory level of the hormone has a beneficial effect on the chorionic villi.
In addition to creating conditions in the female body for the development of pregnancy, hCG performs the function of activating the activity of the adrenal glands and gonads of the fetus, as well as Leydig cells that produce testosterone in male embryos. It should be noted that this substance is also found in the body of the stronger sex, and if its concentration does not exceed normal parameters - 5 mU/ml, then there is no cause for concern.
Features and functions of β-hCG
Value for pregnancy diagnosis
Human chorionic gonadotropin is a special hormone that plays an important function in confirming the fact of pregnancy, its development and possible deviations from the norm. Based on the data obtained as a result of a blood test for hCG, the diagnostician determines the presence of chorionic tissue in the body, which is a consequence of the birth of a new life.
It has long been recognized by many experts that the most reliable way to confirm pregnancy in the early stages is to donate blood for hCG. Well-known rapid tests, with the help of which any woman can independently check the presence of conception, operate on the principle of determining this hormone in the urine. The differences between the described methods are that the level of hCG required for determination in the blood is formed several days earlier than in urine.
If the process of gestation proceeds normally, without any deviations, then the concentration of the hormone doubles every 1.5-2 days, and its maximum value is reached at the onset of 10-11 weeks. Later, its level gradually decreases, which is associated with the end of the formation of the placenta and a decrease in the need for more hCG.
Types of analyzes
In laboratory practice, two types of this study are used - this is the determination of the level of total hCG and free β-hCG. Their scope of application has some differences.
Total hCG
Studying the level of total hCG is an important diagnostic aspect of early determination of conception, when a rapid test is not yet able to detect it. If pregnancy develops normally, then the overall level doubles and reaches a maximum at approximately 11 weeks. In the second trimester, a woman will be recommended to donate blood for such an examination when undergoing prenatal screening - a triple or quarter test.
Free β-hCG
This type of analysis is used to identify trophoblastic neoplasms in women - hydatidiform mole (embryo development abnormalities), choriocarcinoma, and in men, testicular (testicular) oncology. A pregnant woman also needs to undergo a blood test for β-hCG during screening in the first two trimesters to determine the risks of having a child with Down or Edwards syndrome (trisomy 18).
A positive result of this study classifies a pregnant woman as a risk group, but it is not one hundred percent evidence of the presence of abnormalities in the chromosomal makeup of the fetus. For sufficient monitoring, it is recommended that pregnant women be tested for free β-hCG between 8 and 13 weeks and 15 and 20 weeks.
For women who have a negative hereditary factor, expressed in the presence of congenital defects, a history of Down syndrome, hereditary diseases in the family, as well as age over 35 years and exposure to radioactive rays, such an analysis becomes mandatory.
Variety of developmental defects in Edwards syndrome
When is it necessary to donate blood?
There are many more reasons for females to undergo a blood test for hCG than for males. Firstly, there is a suspicion of conception. When is it better to take the test to get a reliable result? To diagnose pregnancy, a hCG test can be performed as early as 3–5 days of a missed period or on the 12th day of expected conception.
Although this hormone will be detected in the blood a week after pregnancy, the reliability of such results is still low, and most likely the doctor will recommend donating a blood sample again. To track the dynamics of the increase in the concentration of the substance, you should carry out this manipulation at least three times with an interval of 2 days and at the same time try to stick to the same time.
Other reasons that answer the question of why they donate blood for hCG include:
- amenorrhea or prolonged menstrual disorders;
- determining the quality of an induced abortion;
- conducting dynamic monitoring of pregnancy development;
- prenatal search for fetal malformations in the early stages;
- suspicions of a threat of spontaneous abortion (miscarriage);
- identifying signs of an undeveloped pregnancy;
- diagnosis of neoplasms – chorionepithelioma;
- detection of risks of ectopic pregnancy.
Also, control over human chorionic gonadotropin is carried out in order to monitor patients who have suffered trophoblastic oncological diseases, and checking its level allows timely monitoring of the occurrence of relapses. In men, such a study is used only to diagnose tumors in the testicles.
How to prepare
Before you undergo this test independently if you suspect pregnancy or pathology, you should ask your doctor in advance where blood is taken for hCG and how to take the test correctly. All this information will be the key to obtaining reliable results and avoiding repeated manipulations. So, the donation rules include the basic principles of preparing for taking a venous blood sample for testing in a laboratory setting, which includes the following recommendations.
The biomaterial is collected according to the standard formula for taking blood from a vein
The procedure is carried out on an empty stomach, or if it is not possible to maintain complete hunger, try to calm it down with a glass of unsweetened tea with one cracker. If you have a morning blood draw, you may eat the night before and then fast for at least 8 to 10 hours.
If a patient takes medications for any reason, his attending physician must know about this before prescribing this examination. The concentration of chorionic hormone can only be influenced by products made on its basis. These drugs include medications used to induce ovulation or for infertility.
According to a wide range of experts, no other therapeutic agent is capable of changing the level of this substance in the blood. In order to subsequently avoid questions about whether the hCG analysis could be wrong, you should not carry out the procedure earlier than 4-5 days of missed period, and after curettage, do the test 1-2 days later.
How quickly can you find out the results?
The concentration of hCG is studied using enzyme immunoassay diagnostics of blood plasma. How long the tests take will depend on the specific clinic where the test was performed. In the vast majority of laboratories, you can use the express method, in which the results will be ready within 1–2 hours from the moment the blood was taken.
For diagnostic institutions located in remote settlements, completion times may increase due to the need to transport biomaterials to another region. Then the patient will be able to receive the examination result no earlier than 24 hours. To speed up this process, many laboratories use the Internet so that the patient can view the answer in his personal account on the clinic’s website or send them by email.
Attention! Do not forget that in some laboratories the normal values may differ due to the quality and features of the equipment used, so it would be optimal if the patient donates blood in the same clinic.
Interpretation of data and possible deviations from the norm
Like all other substances that make up the molecular basis of our body, hCG has indicators that are defined as the norm for various conditions and categories of patients. Its deviations may be evidence of a certain number of pathological processes that have varying degrees of danger to humans. Therefore, the interpretation of the data obtained should be carried out by a qualified specialist who knows all the intricacies of clinical research. You can read in detail about deciphering the results of a blood test for hCG.
As previously noted, the level of hCG accepted as normal may vary, and this is due to gender differences, as well as age and body conditions. So, for example, in healthy men and non-pregnant women, the concentration of these hormones should not exceed 5 mU/ml, while in the first, hCG may even be completely absent and this is also normal.
But for pregnant women, the values change every week and even several days. To make it easier to interpret the study materials, special tables were created containing standard indicators for each specific period of pregnancy. But to adequately assess such values, a woman is recommended to be examined in the same laboratory.
Deviations in the level of hCG with an upward shift in non-pregnant women and males often indicate the formation of tumors in the intestines, kidneys, lungs, uterus, tescules, etc. Exceeding its norm in the blood is typical when taking hCG-containing medications and is also noted a few days after the abortion.
Table of changes in hCG concentration by day from conception
During pregnancy, growth of the substance is observed due to:
- taking medications based on progesterone;
- early toxicosis, gestosis, diabetes mellitus;
- multiple or extended pregnancy;
- chromosomal abnormalities of the embryo.
When diagnosing low hCG parameters in pregnant women, the doctor must immediately take further measures to find the causes of this deviation. Since the mark drops by more than half from normal parameters, it may mean:
- ectopic or terminated pregnancy;
- threat of self-abortion, insufficient placental function;
- death of the fetus in the womb in the later stages;
- true (biological) post-term pregnancy.
Values within the range of 5–25 mU/ml are not considered as confirmation or refutation of the fact of conception, so it is worth repeating the procedure after 2 days.
The hormone human chorionic gonadotropin actively begins to be produced in a woman’s body immediately from the first day of pregnancy. Therefore, women who are actively planning a pregnancy need to know when they can donate blood for hCG in order to accurately determine the fact of pregnancy.
When is the best time to take a hCG test for pregnancy?
Already a week after the expected conception, by taking a hCG blood test for pregnancy, you can find out whether it has occurred or not. This method of diagnosing pregnancy has been the most accurate for many years. Also, after receiving the test results, you can find out the exact duration of pregnancy. Human gonadotropin in a woman’s body is secreted by the membranes of the embryo and is called chorion, and its presence in the blood indicates pregnancy.
Despite the fact that the hormone human chorionic gonadotropin begins to be produced from the first days of fertilization, if a woman knows the exact date of conception, doctors recommend taking an hCG test 3-4 weeks from the first day of the last menstruation.
HCG is considered a good diagnostic tool for determining a normal pregnancy. Determining the level of this indicator in the blood is a good prognostic factor in terms of whether the pregnancy is healthy or not. This method consists in the fact that the level of gonadotropin in a woman’s body as pregnancy progresses should. The largest doubling of hCG occurs in the first four weeks of pregnancy, in the absence of pathologies. During this period, the hCG level increases every 2-3 days. After this, the level of increase in the hormone slows down, and its maximum concentration is reached by week 10, after which it begins to gradually decrease. If the hCG level stops growing or, conversely, begins to decrease earlier than expected, you should consult a doctor. This is necessary in order to exclude possible complications, because this may indicate developmental pathologies.
How to take the test correctly?It is better to take a hCG test for pregnancy in the morning and preferably on an empty stomach. The day before donating blood, it is recommended to limit the consumption of fatty and fried foods, alcohol, and eliminate physical activity. It is not recommended to donate blood immediately after an ultrasound, x-ray or physiotherapeutic procedures. HCG is a unique hormone and there are no analogues to it, so even if you took hormonal drugs, they cannot affect the results, much less lead to the appearance of false ones. 
But you should still warn the laboratory assistant about taking any medications.
The analysis is studied over time, and therefore it must be taken two or three times, with an interval of at least three days. It is necessary to donate blood in the same laboratory, at the same time of day, for more reliable results. Repeated hCG testing helps track the progress of pregnancy. This is especially true for women at risk of miscarriage, because in the early stages this analysis is the only safe way to find out if everything is okay with the baby.
Many expectant mothers who have to take pregnancy tests do not have a very good idea why the hCG result is so important and what this hCG actually is. No less questions are raised by the effect on hCG result of the number of days after ovulation or, abbreviated as DPO. All this information is very important for understanding how to take the test correctly, so that the data is correct, and also when you can take this test, that is, how many days after conception it can show that you are expecting a child.
What is hCG?
Human chorionic gonadotropin or simply human chorionic gonadotropin (abbreviated hCG or hCG) is a specific hormone, the level of which is one of the main signs for determining pregnancy. This is due to the fact that when the fertilized egg attaches to the uterine wall, increased production of this substance begins in the cells of the fetal membrane (chorion), which is extremely important for normal gestation. The hormone consists of alpha and beta particles, with free beta hCG being the most important.
Gonadotropin plays the role of a kind of “controller” of the production of other hormones, namely progesterone and estrogen, the most important for gestation.
HCG does not necessarily indicate pregnancy - it can be elevated for other reasons, including in men, which will be mentioned later.
How does hCG level affect pregnancy detection?
The principle of the simplest pregnancy test, carried out independently (the so-called rapid test), is based precisely on the hCG results. The reagent it contains is able to interact with this hormone, and if the composition of the urine has changed, the level of hCG will indicate pregnancy. The most sensitive tests even detect pregnancy in the early stages, before the woman begins to have a delay.
As practice shows, pharmacy tests can make mistakes, more often in the direction of denying pregnancy.
The percentage of erroneous tests significantly exceeds the advertising promises of manufacturers. Therefore, to correctly determine pregnancy, the best option would be to donate blood to a laboratory. But first you need to decide when to donate blood for hCG so that the test correctly determines your condition.
Blood test for hCG - level depending on DPO
It makes sense to take an hCG test only if you take into account the period that has passed since the moment when conception supposedly occurred. And here such an indicator as DPO is important. The time period from the end of ovulation is important because when the test is taken immediately after the end of ovulation, the fetus has not yet had time to gain a foothold in the uterus and human chorionic gonadotropin is not produced. Therefore, decoding hCG will reveal that its level corresponds to the normal norm.
If hCG is less than 5 mIU/ml (i.e. milli in 1 milliliter of blood - a special unit of measurement accepted throughout the world), then the woman is not pregnant. Pregnancy is confirmed when the value is 25 or higher mIU/ml. On average, in the second to fourth week the hormone level reaches one or two thousand - this means that it is already possible to more or less accurately determine the period. Before this, one has to rely on fairly approximate results of an ultrasound examination. When the hCG content is equal to a thousand (or more), the ultrasound already shows, at a minimum, a gestational sac.
When to go for analysis?
It is advisable to undergo a laboratory blood test for hCG for the first time during pregnancy no earlier than on the fifth or sixth day from the beginning of a delay in menstruation. The countdown should be carried out from the middle of the cycle, given that the highest probability of fetal implantation occurs at the 9-10th DPO. There is no point in doing analysis before, because... a negative result is very possible.
How to prepare for an hCG test?
How to get tested for hCG levels? Here it is very important to strictly follow the rules of delivery. The slightest violation can cause a change in blood composition and, as a result, an error in the hCG analysis, which can have serious consequences during pregnancy. After all, without knowing that you are pregnant and without changing your lifestyle accordingly, you risk harming your unborn child.
So, if you intend to take a blood test for pregnancy, you must comply with the following conditions:
- the analysis is carried out in the morning, no later than 10 o’clock, strictly on an empty stomach;
- starting from the day before taking the test, do not drink alcohol or take medications under any circumstances;
- also, when preparing for the hCG analysis, you should avoid smoking (at least two hours before the test), fatty foods, and physical activity;
- before analysis, it is better to protect yourself from stress - emotional overload can also affect the results of the study;
- It will most likely not be possible to correctly decipher the hCG analysis if shortly before the test you underwent an x-ray, ultrasound, massage, physiotherapy, etc.
The same rules apply for all subsequent tests. Most often, the results are ready within 24 hours after the blood is taken.
HCG level standards during pregnancy
As a rule, a woman undergoes laboratory analysis of hCG during pregnancy regularly in the first three months. If pregnancy is proceeding normally, a beta hCG analysis (that is, a test for its quantitative content in the blood) shows a doubling of concentration approximately every two to three days. It is necessary to take into account that, although hCG levels for a pregnant woman are taken into account from the very first week, at this time they differ little from those before pregnancy. It is also important to take into account that the weekly hCG rate in one laboratory may differ slightly from another. Therefore, you should check the standards of the laboratory where your tests are taken.
Table of hCG levels during pregnancy by day
If the hCG analysis reveals that the hormone is produced in insufficient quantities, the fetus will not be able to stay in the uterus, that is, a miscarriage is possible in the early stages of pregnancy. In the laboratory, you can obtain a special regulatory table that reflects the gradual changes in the level of the hormone, that is, for how long and within what limits it can fluctuate. The level of hCG in the blood of a woman expecting a child continuously increases during the first three months of pregnancy. The maximum concentration is reached in the tenth to eleventh week, then it gradually decreases and subsequently does not change during the entire period of pregnancy, until delivery. You should also take into account the difference between the hCG norm during a healthy pregnancy and the indicators that the analysis gives if an ectopic pregnancy is detected.
Important when deciphering the hCG test
During pregnancy, when deciphering a laboratory analysis for hCG levels, a number of nuances should be taken into account:
- the laboratory norm, as mentioned above, may be different, so you need to clarify this information in your laboratory when you are going to take an hCG blood test;
- if a blood test for hCG shows a discrepancy with the standards, this does not mean that there are serious grounds for alarm - the hCG analysis is indicative in dynamics, i.e. final conclusions can be drawn if the results of the analysis do not change when retaken two to three days later;
An hCG pregnancy test usually shows the duration of pregnancy, starting from the day of conception, and not from the end of menstruation.
Antibody test for hCG - why is it needed?
If the body produces antibodies to hCG during pregnancy, this negatively affects hormonal levels as a whole, which can ultimately disrupt the development of the embryo and lead to miscarriage. A pregnant woman is given an antibody test in the first three months to determine whether the unborn child has any pathologies. In addition, special importance is attached to this analysis in the following cases:
- the pregnant woman's age exceeds thirty-five years;
- the presence of serious pathologies in relatives of the expectant mother.
If the hCG level is not normal
If you have followed the correct timing of the test and correctly calculated your DPO, and the deciphered analysis reveals that hCG rises too slowly for your period, this may indicate that the fetus is fixed outside the uterus or has died (the latter - if the hCG level decreases in the second or third trimester). In addition, complications such as:
- frozen pregnancy;
- there is a threat of miscarriage;
- dysfunction of the placenta.
In addition, this may mean that the pregnancy is “post-term.” Be that as it may, the result should be alarming only when it shows a decrease in the concentration of the hormone by 50 percent or more in relation to the established standards.
What if hCG is elevated?
An excessive increase in hCG levels likely means an error was initially made in determining the gestational age. If there is no doubt about the timing, the concentration of the hormone may increase for the following reasons:
- you suffer from toxicosis, early or late (preeclampsia);
- you have diabetes;
- you are carrying not one child, but twins or triplets;
- you are taking steroid medications.
In addition, the concentration of hCG increases if the fetus develops chromosomal pathologies. This most often occurs with Down syndrome.
What are the dangers of elevated hCG if there is no pregnancy?
Quite often the question arises whether the test can detect an increase in hCG when a woman is not pregnant. This may happen if you take hormones or have a test a few days after your abortion. If these factors are absent and there is no pregnancy, this result may indicate the presence of oncology. Moreover, the latter applies not only to women, but also to men.
HCG test - how and where to take it?
When there is a clear delay in the menstrual cycle, the DPO has been calculated, a pharmacy rapid test has been completed and everything indicates that you are pregnant, the most important practical question arises - how to take an hCG test, where to go for this?
At the antenatal clinic, if you inform your local gynecologist about your delay, he will first refer you for this examination. But many nowadays prefer to use the services of private clinics, where they do not have to stand in line and once again be exposed to stress when their nerves are already tense. Of course, this decision is primarily influenced by how much an hCG test costs in such a clinic.
Katya Milai, Kaluga:
Is it possible to drink water before taking HCG? I usually don’t drink water or tea, will it have any effect?
Answer from our expert
is human chorionic gonadotropin, a substance of polypeptide nature, a hormone produced in quantities sufficient to be detected already in the first week of pregnancy.
An important requirement in this case is the period after the last meal, which should be at least 4 hours.
The fact is that eating food, drinks, especially coffee, stimulates metabolic processes and hormonal fluctuations, in particular. Therefore, the result may be inaccurate and require re-diagnosis.
If you drink clean water before donating blood, without dyes, gases or flavorings, the hCG level will not change. Some doctors are even of the opinion that it makes no difference when to take the test - the hormone is either present in the blood or not. But this statement is only partly correct. It is not only the presence of the hormone that is important, but also its concentration.
If you donate blood after a meal, the hCG concentration may deviate from the norm, which will necessitate a repeat test. A deviation in concentration indicates pathologies of the fetus or an ectopic, frozen pregnancy, therefore it is better to fulfill the diagnostic requirements and obtain the most accurate data.
Video: When to take an hCG test