Pregnancy Test Accuracy
From LoveToKnow Pregnancy
If you think you might be pregnant, you may be wondering about home pregnancy test accuracy rates.
How Does a Home Pregnancy Test Work?
A home pregnancy test works by measuring the level of human chorionic gonadotropin (HCG) in your urine. This pregnancy hormone is secreted by the developing placenta shortly after fertilization occurs.
Under laboratory conditions, home pregnancy test accuracy is about 99%. However, this assumes that you have followed the test instructions correctly and not done anything to damage the test kit.
False Positives and False Negatives
When discussing home pregnancy test accuracy rates, it’s important to understand the difference between a false positive and a false negative result. A false positive result would indicate that you are pregnant when conception has not actually occurred. A false negative result would indicate that you are not pregnant when you really are.
Generally, false negative results are more common than false positive results. Most false negative results are caused by user error, while false positives are more often attributed to a chemical pregnancy, interference caused by certain fertility medications, or other rare medical conditions.
Accuracy and Test Sensitivity
If you’re considered about home pregnancy test accuracy, you may want to purchase a test that has a higher sensitivity to detect HCG levels earlier in your pregnancy.
Typically, HCG levels are measured in milliInternational Units (mIU) or amounts equal to 1/1000th of an IU per milliliter. This means a home pregnancy test with a sensitivity of 20 mIU/ml is more sensitive than a test with 50 to 100 mIU/ml.
A 20 to 25 mIU/ml test allows for earlier detection of pregnancy, possibly as soon as eight days after conception. However, it’s important to remember that conception may take place several days after date of intercourse. Do not use the date of sexual intercourse as the day of conception when determining which test you should purchase.
Tips for Improving Pregnancy Test Accuracy
If you’re concerned about getting your pregnancy test accuracy, remember the following tips as you’re completing the test:
- Wait until your period is at least one week late, particularly if you’ve had irregular menstrual cycles in the past. Testing on the first day of your missed period results in pregnancy test accuracy rates of about 80%.
- Store your test at the proper temperature and never leave it in a hot car. Extreme heat or cold can damage your home pregnancy test.
- Follow the test’s timing instructions. Waiting too long to read the results or reading the results before the specified time period has passed can cause a false positive or false negative result.
- Take the test right away in the morning, when your pregnancy hormone levels should be the highest.
- Don’t consume large amounts of coffee, soda, water, or other beverages before the test. This can affect the levels of HCG in your urine.
- If you don’t understand how to take your home pregnancy test, call the customer service number listed in the instruction pamphlet for further assistance.
- Never use a test that has passed its expiration date.
Comments
Anway, I went on birth control and had horrible side effects. the doc told me to go off for one week and i began to bleed for 2 weeks straight. the day after the bleeding stopped, i had unprotected sex and started to feel pregnant this past weekend. monday i took a test, extremely faint line. the next day i took another but late in the noon and there was nothing. the next day i took one in the morning and i got a very thin faint blue line that took over 10 mins to pop up, but the nausea and breast tenderness is increasing. today i took a test aroun 1pm and there was no line until around 5 minutes later and it was very faint as well. im going to do a test upon rising tomorrow and hopefully this will tell me for sure. i used a store brand 5 days early test since its the 5th and i had to have conceived on the 25th of may for this...it takes roughlt 9-12 days for implantation to settle and this is when these tests should work, however mine are so light...my period should be here in about days, so hopefully the linews should get darker by then if i am. hcg levels double every 2 days.
-- Contributed by: TamiRMarilyn,
since you took the tests in different months, I think they were accurate and you are not pregnant. It's not unusual for a woman's cycle to take a few months to return to normal after coming off the pill, but you shouldn't be missing it for three months. You might want to give your OB/Gyn a call in case they want to do an exam.
-- Contributed by: HollySwansonI missed my period about 3 months ago, last one was February 20th. I took two pregnancy tests, the clear blue, one in April and the other May 22nd. They both said negative. Is there a possibility that I'm pregnant or is my body just messed up. I've always been regular about my periods. I was taking birth control pills, but stopped them the beginning of February. Please help.
-- Contributed by: MarilynThis page has been accessed 5,977 times. This page was last modified 20:21, 30 August 2006.
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