The Beta-hCG reference values are as follows (may vary according to the method and reagents used):
In non-pregnant, healthy men and women, the result is NEGATIVE.
To pregnancy diagnosis:
• From 5 to 50mU / ml: undetermined
• Above 50mU / ml, healthy woman: POSITIVE
THE human chorionic gonadotrophin (hCG), is a hormonal glycoprotein synthesized in the syncytial trophoblastic cells, with the function of maintaining the corpus luteum in the first trimester of gestation, when the placenta assumes the progesterone production function. The hCG molecule is composed of units, alpha and beta, and the beta subunit is specific to pregnancy. Beta-hCG screening can be done in the blood or urine when pregnancy is suspected (normal or ectopic), abortion, gestational trophoblastic disease, and germ cell tumors (ovarian and testicular tumors).
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- The patient should fast 4 hours prior to the examination and can be performed on the day of probable menstruation. In the case of urine, one should preferably take the first urine in the morning, which contains a higher concentration of hCG;
- The diagnosis of pregnancy should not be based solely on the result of the laboratory examination, but on the correlation of the test result with the clinical signs and symptoms. A negative result should not be considered to exclude the possibility of pregnancy - it is suggested to perform a new test on sample harvested after 7 days;
- When the result is indeterminate, special attention on evolution, with repetition after 72 hours;
- The diagnosis of pregnancy can be made from the second day of menstrual delay and in normal pregnancy the concentration doubles every 2 days from the 2nd to the 5th week of evolution;
- Serial determinations can be used in the suspected abnormal pregnancy when the rate of elevation in HCG concentration is lower than expected or even decreasing in cases of miscarriage or ectopic pregnancy;
- Urine screening is used as a screening method because its results are qualitative and the detection threshold is lower than in the blood;
- Samples from patients with trophoblastic diseases such as choriocarcinoma or hydatidiform mole secreting hCG can produce positive results in the absence of pregnancy;
- Low hCG concentrations may occur in healthy, non-pregnant women;
- False-positive results may occur rarely in samples containing high concentrations of LH (menopause). Therefore, positive results in women over 45 years should be interpreted with caution.
The interpretation of the results of the examination should be performed by the doctor who requested it, together with the history and clinical examination. For more information, consult a general practitioner or preferably a gynecologist.
