How, when and for what to take a blood test for the hormone hCG

Human chorionic gonadotropin( hCG), or a pregnancy hormone, is a key indicator of the onset and development of pregnancy. It is produced by cells of the embryo shell( chorions) and this process begins at the moment when the fetal egg is already fixed in the uterus. However, the content of HCG in the blood does not always indicate the onset of pregnancy.

  • value hormone hCG
  • Indications for analysis
  • types of analyzes
  • Total hCG
  • Free b-hCG
  • Preparation
  • Analysis
  • Explanation
  • results Norm
  • Raised index
  • Reduced rate

value hormone hCG

certain level of hCG hormone may indicatefollowing conditions:

  • The maternal organism is preparing to "embrace" the embryo.
  • In the first weeks of pregnancy, the activity of the yellow body is maintained until the end of the placenta formation process( about sixteen weeks) and the "production" of progesterone is accelerated.
  • The activity of the adrenal and gonadal glands of the embryo is stimulated.
  • Activation of cells producing testosterone in a future boy occurs.

  • Probability of oncological problems.
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Indications for analysis of

A blood test for hCG level is necessary when:

  • reveals pregnancy on a short term( from 5-6 days after fertilization);
  • determining an ectopic pregnancy;
  • tracing pregnancy in dynamics;
  • fears about a possible threat of miscarriage or fetal fading;
  • need to identify intrauterine deviations in fetal development;
  • for abortion( to assess whether fetal egg removal occurred);
  • diagnosis and identification of the causes of delay or lack of menstruation for a long time;
  • suspicions of the presence of trophoblastic tumors( when the spermatozoon merges with the egg, but the fetus does not develop, and the grape-like cysts appear in the uterus) and to monitor the condition after the transfer of a similar disease;
  • occurrence of malignant neoplasms from embryonic tissues, digestive system, tumors of testicles and ovaries.
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Types of assays

There are two types of analysis: total hCG and free b-hCG.

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General HCG

Diagnosis of the level of total hCG allows you to detect pregnancy at the earliest possible date. If it develops correctly, the level of hormones increases 2 times every 2 days, reaching a maximum value by the 11th week, after which it begins to decrease smoothly.

Once again, the analysis for general hCG is given by future mothers already in the second trimester in conjunction with other studies( perinatal screening) for the purpose of early diagnosis of intrauterine fetal development pathologies.

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Free b-hCG

This assay is given for suspected cases of trophoblastic tumors( bladder skydiving, choriocarcinoma) or testicular oncology in men and ovaries in women.

It is performed in the first two trimesters of pregnancy in screening to identify the risks of fetal chromosomal and genomic pathologies( Down's Syndrome and Edwards Syndrome).

However, even if the analysis for free hCG was positive, do not worry before the time that the baby is born sick. This result includes a mother at risk and needs more careful monitoring by doctors.

Blood for free beta-hCG is recommended to be taken from 8 to 13 and from 15 to 20 weeks. This procedure is especially important for those women who:

  • is over 35 years old;
  • were susceptible to radiation exposure;
  • have close relatives with Down syndrome, the presence of congenital malformations or hereditary diseases.
All that a woman needs to know about pregnancy planning
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Preparation of

Before submitting the analysis, it is necessary to prepare.

  • Notify physician about medications taken.
  • Eliminate physical activity( including sexual contact), smoking and alcohol.
  • Eight hours before the procedure, it is advisable not to eat anything, since the blood test for HCG is given on an empty stomach.
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Analysis is carried out in the morning. For the study, blood from the vein is taken. The result is based on enzyme immunoassay analysis of serum.

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For the purpose of confirming pregnancy and determining its term, a blood test for HCG can be taken if the delay in menstruation is at least 3 days. For more accurate results, it is recommended to repeat the analysis after 2 days. Carrying out a blood test for hCG before the delay can show an incorrect result due to insufficient concentration of the hormone in the blood.

How much the blood test for HCG is done depends on the specific laboratory. Some institutions provide an express analysis service, the result of which is ready after an hour and a half. Often the expectation of the result takes about a day.

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Explanation of results

The hCG rate is determined individually in each specific case, therefore it is better to consult a specialist for interpreting the results.

The accuracy of the blood test for hCG is high enough, but for questionable results it is recommended to repeat the study, observing all the necessary requirements.

It is important to know that the norm indicators in different laboratories may differ, therefore it is desirable to take the repeated analysis in the same place as the first one.

It is important to know that sometimes a blood test for hCG can be wrong. In some cases, a false-positive blood test for HCG indicates a "malfunction" of the woman's hormonal background or indicates the appearance of tumors.

At the same time, there is sometimes a false-negative blood test for HCG( even if the pregnancy has already been confirmed by the doctor) due to late ovulation and fetal attachment, and also if the fetal egg is fixed outside the uterus.

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The normal hCG values ​​are presented in the table.

Normal values, mU / ml
Men and non-pregnant women 0-5
Re-examination required 5-25
Pregnant women
at week 1-2 from conception 25-156
at 2-3 weeks 101-4870
at week 3-4 1110-31500
for 4-5 weeks 2560-82300
for 5-6 weeks 23100-151000
for 6-7 weeks 27300-233000
for 7-11 weeks 20900-291000
at the 11-16 week 6140-103000
at the 16-21 week 4720-80100
on the 21-39 week 2700-78100
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Increased indicator

If the level of hCG is elevated in the blood of a male or non-pregnant woman, this may indicate the presence of oncological formations. Also, the increase is noted within five days after abortion and with the use of drugs containing hCG.

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The reason for the high level of hCG in pregnant women can be. Fattening of twins or triplets.

  • Diabetes mellitus.
  • Toxicosis or preeclampsia.
  • Pregnancy pregnancy.
  • Chromosomal abnormalities of the fetus.
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    Often, a low level of blood test for hCG indicates:

    • ectopic pregnancy;
    • miscarriage of pregnancy;
    • a frozen pregnancy;
    • threat of abortion( miscarriage);
    • delayed embryo development;
    • deficiency of placenta development;
    • fetal death in late pregnancy.

    Low hCG( as, indeed, any deviation from the norm) requires immediate contact with a doctor.

    • May 08, 2018
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