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Pregnancy test wrong? How reliable are the results

MEDICALLY REVIEWED
Schwangerschaftstest falsch? So sicher sind die Ergebnisse


Key Takeaways

  • A false positive pregnancy test - is that even possible? And what about false negative results? Are you unsure how reliable pregnancy tests are?
  • In this article, you'll find out how these tests work, the reasons for false results and how you can improve their accuracy.
  • Get the most important information on possible sources of error and find out the best way to proceed if the results are unclear.

Have you ever taken a pregnancy test and then wondered how reliable the result is? You’re not alone. Many women question how accurate their test really is, especially when it comes to false positive results. Pregnancy tests play an important role in family planning, but their accuracy can be influenced by various factors.

In this article, you’ll learn how pregnancy tests work and what can cause false results. We’ll discuss what you can do to improve accuracy and how to deal with unclear results. Whether you have a positive test result but no period, or if you have signs of pregnancy but the test is negative, you’ll find answers here. This will help you better understand what your test result means and what next steps might be appropriate.

How Does a Pregnancy Test Work?

Pregnancy tests are based on detecting the pregnancy hormone hCG in your urine. This hormone is produced by the developing placenta once a fertilized egg implants in the uterus.

Common pregnancy tests use an immunochromatographic method. When you wet the test strip with urine, the hCG binds to a dye-labeled antibody on the test strip. This complex then moves to a test zone, where it binds to a second antibody and triggers a color reaction. One or two lines appear.

Most tests detect hCG at a concentration of 25 mIU/mL. Early pregnancy tests can even react to 10 mIU/mL or less, making them particularly sensitive. hCG is detectable in urine about nine days after conception, with a concentration of about 0.93 mIU/mL. The Ovy pregnancy test detects the pregnancy hormone hCG in urine at a concentration of 10 mIU/mL. The Ovy pregnancy test can be used as early as 5 days before the due date of your period. The test provides a 99.9% reliable result within five minutes, comparable to a medical rapid test.

For a reliable result, it’s best to take the test in the morning, as the hCG level is highest in the first morning urine. When used correctly, many manufacturers promise 99 percent accuracy on the day of your expected period.

Reasons for False Results

Reasons for False Positive Results

False positive results are very rare but can occur. Possible causes include:

  • A recent pregnancy, miscarriage, or birth

  • Certain ovarian cysts

  • Taking hCG-containing medications, especially during fertility treatments

  • Chemical pregnancy: A very early pregnancy loss

  • Ectopic pregnancy: Implantation outside the uterus (about 1 in 90 pregnancies)

  • Molar pregnancy: A rare complication in early pregnancy

  • Artificial insemination: Previous administration of hCG-containing medications

  • In very rare cases: Cancers

Reasons for False Negative Results

False negative results occur more frequently. Possible reasons include:

  • Testing too early: hCG levels are still too low

  • Testing too late: hCG levels decrease in later pregnancy

  • Diluted urine from excessive drinking before the test

  • Using expired or improperly stored tests

  • Not using the first morning urine with the highest hCG concentration

  • In rare cases: Ectopic pregnancy (less than 3% negative result)

Measures to Avoid False Results

To get reliable results, you should follow a few important points. Ideally, perform the test from the first day of your missed period or use an early test no more than four days before. It’s best to use the first morning urine, as it has a higher hormone concentration. For tests taken after a missed period, you can also test at other times of the day.

Ensure the correct use of the test and avoid user errors. Do not use expired test kits. If you get a negative result shortly after a missed period, repeat the test after about three days. This increases reliability.

If you are unsure or have persistent symptoms, seek medical advice. In practice, a urine or blood test can more accurately confirm a pregnancy. Note that certain medications or hormone preparations can affect the result.

Conclusion

Pregnancy tests are an important tool for early detection of a possible pregnancy. Although they provide reliable results in most cases, various factors can lead to false outcomes. To improve accuracy, it’s best to take the test in the morning and follow the instructions carefully. If you are unsure about the result, or even after a positive result, you should visit your gynecologist to clarify or confirm the result.

Ultimately, pregnancy tests provide a good first indication, but they are not infallible. A positive result does not always mean pregnancy, just as a negative result does not rule out pregnancy. By understanding possible sources of error and using the test correctly, you can increase reliability. This provides a better basis for planning further steps for your health and family planning.


Medically Reviewed

This text was created by medical editors on the basis of specialist medical literature and current studies. Our aim is to work scientifically, identify sources and regularly check that the content is up to date.


References & Literature

  1. Bundeszentrale für gesundheitliche Aufklärung (BZgA): www.familienplanung.de. Der Schwangerschaftstest
  2. Bundesverband der Frauenärzte in Zusammenarbeit mit der Deutschen Gesellschaft für Gynäkologie und Geburtshilfe: Frauenärzte im Netz. Anzeichen einer Schwangerschaft & Schwangerschaftstest