A Clearblue pregnancy test can occasionally give a false positive result, indicating pregnancy when the person is not actually pregnant. There are a few key reasons why a Clearblue test may show a false positive.
What is a false positive pregnancy test?
A false positive pregnancy test occurs when the test says it detects the pregnancy hormone hCG but the person is not actually pregnant. This leads to the test displaying a positive result when it should actually be negative.
False positive test results are more common with home pregnancy tests than with those administered by a doctor. Still, even doctor-administered tests can very occasionally produce a false positive.
What causes a false positive pregnancy test?
There are a few possible causes of a false positive pregnancy test, including:
- Chemical pregnancy – Also known as a very early miscarriage, a chemical pregnancy occurs when an embryo implants but stops developing shortly after. Enough hCG hormone may be produced to trigger a positive test.
- Ovarian cysts – Cysts on the ovaries can sometimes produce small amounts of hCG.
- Perimenopause -Changing hormone levels around perimenopause can occasionally cause a false positive.
- Hormone injections – Injections containing hCG, like some fertility treatments, may cause false positives.
- Medications – Very rarely, certain medications could cause a false positive pregnancy test.
- Evaporated urine – Allowing the urine sample to evaporate before reading the test may concentrate hCG and cause a false positive.
- Expired test – Outdated tests can sometimes provide inaccurate results.
- Ectopic pregnancy – A pregnancy implanted outside the uterus may produce enough hCG for a positive test but will not show up on an ultrasound.
How accurate are Clearblue pregnancy tests?
Clearblue pregnancy tests are highly accurate when instructions are followed precisely. According to the manufacturer, Clearblue tests have the following accuracy:
| Test Type | Sensitivity | Accuracy |
|---|---|---|
| Clearblue Early Detection | 25 mIU/mL hCG | 99% accuracy from day of expected period |
| Clearblue Plus | 50 mIU/mL hCG | Over 99% accuracy from day of expected period |
Sensitivity refers to the threshold of hCG the test can detect. The lower the number, the earlier pregnancy can be detected. Accuracy refers to how often the test gives the correct result.
Tips for maximizing accuracy
To get the most accurate results from a Clearblue pregnancy test:
- Follow all test instructions precisely.
- Check the expiration date and do not use expired tests.
- Store the test properly before use.
- Use the test first thing in the morning when hCG levels are highest.
- Do not drink excessive fluids before testing.
How often does Clearblue give false positives?
When used as directed, Clearblue digital pregnancy tests give false positives less than 1% of the time. The vast majority of positive Clearblue pregnancy tests are accurate.
According to one study, out of 2,048 negative urine samples tested by Clearblue Easy, there were 0 false positives. This gives the test a 100% specificity or true negative rate.
Factors that may increase likelihood of getting a false positive Clearblue result include:
- Incorrect use of test, like reading results after 10 minutes
- Use of an expired test
- Existing medical conditions like ovarian cysts
- Use of fertility medications
To minimize false positives, carefully follow all instructions and check test expiration date. Retest with a new kit if you suspect a false positive.
Can a Clearblue test ever be wrong?
While very accurate overall, Clearblue pregnancy tests can occasionally be wrong. Here’s an overview of when Clearblue tests may be inaccurate:
- False positive – The test is positive but the person is not actually pregnant. This occurs less than 1% of the time with Clearblue.
- False negative – The test is negative but the person is pregnant. This is more common with early testing before sufficient hCG has built up.
- Testing too early – There is not enough hCG hormone yet to be detectable. Retesting after a missed period provides the most accuracy.
- Chemical pregnancy – A very early pregnancy loss may cause fluctuating hCG levels and unclear results.
- Ectopic pregnancy – A pregnancy outside the uterus will not be visible on an ultrasound if hCG levels are low.
- Expired test – Outdated tests are more likely to be inaccurate.
Ways to confirm pregnancy after a positive test
If you suspect a false positive pregnancy test, there are steps you can take to confirm:
- Retest with a new Clearblue test, preferably first morning urine
- Get a quantitative hCG blood test from your doctor
- Have an ultrasound to confirm the pregnancy
- Monitor hCG levels through repeat blood tests if ectopic pregnancy is suspected
See your doctor right away if you have signs like abdominal pain along with a positive test, as this can indicate an ectopic pregnancy.
What do Clearblue test lines mean?
Clearblue tests may show one or two lines to indicate if pregnancy has been detected. Here is what each result means:
| Test Result | Meaning |
|---|---|
| Single blue line | Negative result – no pregnancy detected |
| Plus sign (+) | Pregnant result on Clearblue Digital |
| Two blue lines | Pregnant result on Clearblue non-digital tests |
A faint second blue line, even if very light, means the test is detecting pregnancy. Results should not be read after 10 minutes, as any faint lines may be evaporation lines and do not count as positive.
What an invalid Clearblue looks like
If a Clearblue test is faulty, you may get an invalid result with no lines showing at all. This may occur if:
- Instructions were not followed properly
- Test is expired or has been damaged
- There was an error during manufacturing
If you get an invalid result with no control line, you should retest with a new kit.
How to avoid false positives on Clearblue tests
While false positives are uncommon on Clearblue tests, there are some steps you can take to help avoid inaccurate results:
- Carefully follow all test instructions.
- Check the expiration date on the test and do not use if expired.
- Store the test properly before using.
- Do not take the test apart or modify it in any way.
- Read the results within the specified time frame.
- Retest with a new test if you suspect the result may be inaccurate.
Avoid excessive intake of fluids before taking the test. Use the test first thing in the morning for optimal hCG levels. Setting a timer can help ensure accurate reading of results.
Next steps after a positive Clearblue pregnancy test
If you get a positive pregnancy test result on Clearblue, here are some next steps:
- Retest in a few days with a new Clearblue test, using first morning urine.
- Make an appointment with your doctor to confirm the pregnancy through hCG blood tests and ultrasound.
- Discuss prenatal vitamin and folic acid recommendations with your doctor.
- Calculate your due date based on your last period.
- Adjust medications, diet, exercise routines as needed for pregnancy.
- Stop behaviors like drinking alcohol and smoking if applicable.
Talk to your doctor right away about any warning signs of ectopic pregnancy. Early prenatal care is important for a healthy pregnancy.
Key takeaways
- Clearblue pregnancy tests rarely give false positives, with over 99% accuracy when used properly.
- False positives may be more likely with expired, faulty, or improperly used tests.
- Retest with a new kit if you suspect a false positive result.
- See your doctor for hCG blood tests and ultrasound to confirm pregnancy after a positive test.
- Carefully follow all test instructions to maximize accuracy and avoid false results.
