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Home pregnancy test accuracy

Many home pregnancy tests (HPTs) claim to be 99% accurate on the day you miss your period. But research suggests that most HPTs do not consistently spot pregnancy that early. And when they do, the results are often very faint. If you wait for a week after your missed period, HPTs can be quite accurate. But the accuracy depends on a few factors:

• Following instruction - Be sure to follow the directions and check the expiration date.
• The day you take the test - The amount of hCG or pregnancy hormone in your urine increases with time. The longer you can wait after you missed period, the better the result.
• The time of day - Testing your urine first thing in the morning may boost the accuracy.
• Who uses them - The amount of hCG in the urine is different for every pregnant woman. So, some women will have accurate results on the day of the missed period while others will need to wait longer.
• The brand of test - Some home pregnancy tests are more sensitive than others and better than others at spotting hCG early on.

No matter what results you get, most brands tell users to repeat the test in a few days, no matter what the results. Yes, it’s better for them to make more money having you buy another test. but you can always try another brand. Be more practically, it might be worth the few bucks to take a second test and be sure.

One negative result (especially soon after a missed period) does not always mean you’re not pregnant. All HPTs come with written instructions and most have toll-free phone numbers to call in case you have questions.

False negative pregnancy test

This means your pregnancy test shows that you are not pregnant when you in fact are.

How does this happen? Well, every woman ovulates at different times in her menstrual cycle. Plus, embryos implant in the uterus at different times. So, the accuracy of HPT results varies from woman to woman. If you take the test too early, you can get a false negative. Other things can also affect the accuracy (see below).

This is why most HPTs suggest women take the test again in a few days or a week.

If your HPT is negative, test yourself again in a few days or 1 week. If you keep getting a negative result but think you are pregnant, talk with your doctor right away.

False positive pregnancy test

On the other hand, you could get a home pregnancy test that tells youthat you are pregnant when you’re not. This is known as a false-positive. These are rare.

You may get a false-positive if you have traces of blood or protein in your urine. Various prescription drugs — including diuretics and promethazine (used to treat allergy symptoms and nausea) — also can cause a false-positive result. Also make sure, the test kit is not damaged or expired.

Can a pregnancy test be wrong?

Yes, there are several things that might affect the accuracy of your home pregnancy test.

• Old urine. If you’re collecting urine, do the test within 15 minutes of collecting the sample. And be sure to give the test time to work — but not too much time. Use a clock and go by the time given exactly in the test’s instructions.
• Diluted urine. Do not drink excessive amounts of fluids before the test to increase the volume of urine. This could dilute the hCG levels. This may cause a false-negative result. For the most accurate results, take the test first thing in the morning — when your urine is the most concentrated.
• Certain medication. Most medicines, over-the-counter and prescription (including birth control pills and antibiotics), alcohol and even illegal drugs should not affect the results of a home pregnancy test. But medication that have the pregnancy hormone hCG in them (used to treat infertility) can give a false positive test result.
• Trouble with pregnancy. If there is a problem with the pregnancy, such as an ectopic pregnancy (when the fertilized egg settles in the fallopian tube instead of the uterus), hCG levels may be low and non-detectable by a home pregnancy test.

Read the directions included in the test thoroughly before starting the test and follow every step precisely.

See your doctor if you are unsure about the test’s results.

Missed period but negative pregnancy test

Maybe you’ve missed your period and you feel you are probably pregnant. But the HPT says no. Now what?

Definately take a second, even third test.

But if you keep getting a negative result, you might want to visit your doctor. There are other reasons you have missed your period, such as

• stress
• hormone inbalance
• vigorous, ongoing exercise (such as training for a marathon or other event)
• irregular periods
• thyroid problems
• ovarian cysts
• physical stressors
• dramatically increased or decreased body weight
• even, rotating shifts at work

If a HPT says you are pregnant, you should call your doctor right away. You doctor can use a preganancy blood test along with a pelvic exam to tell for sure if you’re pregnant.

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