False positive pregnancy test - reasons. In which cases is the pregnancy test false positive?

The rapid test is an affordable and simple procedure that allows you to determine the presence of pregnancy within 5 minutes soon after the alleged conception. The reliability of the method, depending on the test generation used, can reach 99 percent. However, it happens that the test is wrong. Is a false positive result possible, what factors can provoke it?

Contents

  • False positive pregnancy test. Principle of work of rapid tests for pregnancy
  • Can the pregnancy test be false-positive
  • False positive pregnancy test - causes
    • False positive pregnancy test. Overdue, spoiled or defective test
    • False positive pregnancy test. Violation of the instructions for use, incorrect evaluation of the result.
    • False positive pregnancy test. Consequences of delivery, medical abortion or miscarriage
    • False positive pregnancy test. Taking drugs against infertility
    • False positive pregnancy test. Menopause
    • False positive pregnancy test.
      • tumors Bladder / choriocarcinoma
      • Ovarian cyst
  • Mythical causes of false positive pregnancy test
    • False positive pregnancy test for hormonal failure
    • False positive pregnancy test before monthly
    • False positive pregnancy test after taking hormonal contraceptives
    • Pregnancy test false positive result forLactation
  • Conclusion

False positive pregnancy test. Principle of work of rapid tests for pregnancy

  • Any rapid test, whether it is a test strip, inkjet or test cassette, works by one principle, reacting to human chorionic gonadotropin( hCG).HCG in an amount of up to 5 mU / ml is produced in organisms of men and non-pregnant women. For the increased production of this hormone in pregnant women is responsible for the chorion and subsequently formed from it the placenta. The rapid increase in the level of hCG begins already 24 hours after the attachment of the embryo to the uterine wall.
  • The most accurate ultrasensitive jet tests are able to recognize the "interesting position" already at an HCG concentration of 10 mU / ml, that is, 7-10 days after conception.

Can the pregnancy test be false-positive

Yes, it can. Although much more often error or misapplication results in a false-negative result. False positive pregnancy test - causes of

False positive pregnancy test. Overdue, spoiled or defective

  • test A faded streak in the test area may appear early in gestation or be a consequence of using a substandard rapid test. Overdue or incorrectly stored rapid tests of different generations and costs are frequent culprits for the appearance of a "ghost strip".

  • No manufacturer of rapid tests for the diagnosis of pregnancy can guarantee an absolute lack of marriage in their products. In order to exclude a false positive test for pregnancy, the testimonials of experienced women recommend testing at least twice by express tests from different parties or different brands. False positive pregnancy test. Violation of the instructions for use, incorrect evaluation of the result
    • When using rapid tests it is important to follow the instructions exactly, otherwise the results may be distorted.
    • The second strip should be painted and placed in the test zone. A white strip in the test area can not be regarded as a positive or false positive pregnancy test - it is a reagent that, with an increased level of hCG, would change color.
    • A strip located on the border of a urine-absorbing part with a test zone is not relevant to pregnancy.
    • The second strip, which appears after the reagent dries, is not a sign of pregnancy. False positive pregnancy test. Consequences of delivery, medical abortion or miscarriage
      • The presence in the woman's blood of hCG after delivery or termination of pregnancy can not disappear in an instant. To remove hCG from the body may need a month and a half. During this time interval, the probability of an erroneous positive result of the rapid test is high.
      • The second strip on the test can indicate a failed pharmacist or the presence of the uterine cavity parts of the fetal egg. False positive pregnancy test. Taking drugs against infertility

        Pregnil, Horagon, Prophase are injections of HCG that are used in the fight against infertility. They contribute to the production of estrogens, the yellow body, facilitate the release of the egg from the ovary. Of course, a test done shortly after injection will be false positive. To achieve a reliable result after the injection should take about 3 weeks. False positive pregnancy test. Menopause

        The normal level of hCG in women in menopause is higher and can reach 14 mU / ml. Test strips are unlikely to react to this increase, but ultrasensitive tests may well "populate".False positive pregnancy test. Tumors

        The presence of any tumors in the body can confuse the pregnancy test. But the most common culprits of the false appearance of the second stripe are trophoblastic neoplasms: bladder skeleton and chorio carcinoma.

        Bleeding( molar) skid / choriocarcinoma

        • Bubble skeleton is an anomaly that does not result in the normal development of the embryo, and its tissues degenerate into cysts resembling grape clusters. It is complete and partial, simple and destructive. Percentage in relation to the total number of pregnancies: 0.02-1%.
        • Molar skid has all the typical signs of pregnancy: increased levels of hCG, early toxicosis, uterine growth. A photo of a false positive pregnancy test with it is no different from a positive test: the strip in the test zone will be bright. Fortunately, the disease is easily diagnosed by ultrasound.

        • With a simple bubble drift, chorionic villi are located in the uterine cavity. But approximately every 5 women with a bladder drift have a malignant destructive form - a choriocarcinoma, in which the disease goes beyond the uterine cavity( or another, similar to it in the structure of the organ), spreading to other organs or tissues.
        • Full bladder skipping( PPD) occurs due to loss of maternal and duplication of paternal genes. Karyotype: 46, XY or 46, XX.In this case, embryonic tissues are completely regenerated.
          For PPH, the uterine size is much larger than the average for the intended gestation period. Patients with PPH experience uterine bleeding, approximately 20 cases out of 100 the disease is transformed into choriocarcinoma.
        • Partial bladder skidding( CHPZ) is a consequence of simultaneous fertilization of an ovum with two spermatozoa / sperm with a double set of chromosomes. Karyotype: 69.XXY, 69.XXX or 69.XYY.
          Embryonic tissues in this case are not completely regenerated, but conceptus is not viable, pregnancy is usually interrupted spontaneously at a period of about 10 weeks.
          In case of emergency, the size of the uterus is less than typical for a specific gestation period, and malignant degeneration of the disease occurs in 5 percent of cases.

        Ovarian cyst

        There is an opinion that a false positive test for pregnancy with a cyst is possible. This is not quite true. To provoke the appearance of a usually faint second stripe in the test zone, a cyst can develop - a cystic benign formation, which is also often called a cyst by mistake.

        Mythical causes false positive pregnancy test

        False positive pregnancy test for hormonal failure

        Hormonal failure can not contribute to an increase in the production of hormone hCG.Consequently, a false-positive express test can not become.

        False positive pregnancy test before monthly

        Menstruation also does not affect the production of human chorionic gonadotropin in any way. Test strips, due to lower sensitivity, are designed for use from the first day of menstruation delay. But tests of the second and third generation are quite capable of detecting a pregnancy even before the anticipated day of menstruation.

        False positive pregnancy test after taking hormonal contraceptives

        Taking oral contraceptives, using an implant, vaginal ring, patches or intrauterine therapy systems does not contribute to increased production of hCG.

        Pregnancy test false positive result for lactation

        When breastfeeding, the prolactin hormone is produced, and lactation has no effect on human chorionic gonadotropin. Hence, breastfeeding can not cause a false positive test.

        Conclusion

        The probability that the positive result of the rapid test will be false is not high. However, in view of the fact that the erroneous appearance of the second strip can indicate health problems, it is important to know, in what cases the pregnancy test is false positive.