Do pregnancy tests lie?

Question

Has anyone ever had at least one Positive pregnancy test, then negatives follow, went to the doctor and got a test done(that came back negative) and then got a blood test and you WERE indeed pregnant? I've heard this has happened a lot. Thanks :)

Answer 1

I'm sure it does happen.

Answer 2

There is absolutely NOTHING in life that is 100% accurate besides the statement, "There is absolutely nothing in life that is 100% accurate."

It's not that they lie, they just aren't always reliable.

Answer 3

Yes! I once had one tell me that I was going to be president.

Really, no. they may have a false reading but it is extremely rare for one to do that. You should take a second one to double check if you ever have doubts.

Answer 4

a test won't tell you you are pregnant if you are not ...but it will tell you you are not pregnant if you are , some people need a blood test to show they are pregnant I've heard a few people like that

Answer 5

sometimes, but to make sure go to the doctor

Answer 6

wait a two - three month and see if ur "getting bigger" or i depends on the test u use

Answer 7

Well they can't "lie." They can just be inaccurate.

And it's not generally because of anything wrong with the test. It's the body of the person taking the test.

When your pregnant, urine tests, and the blood tests, are looking for the presents and levels of the hormone human chorionic gonadotropin (hCG), a glycoprotein that is secreted by the placenta shortly after fertilization.

In some cases, some women's bodies don't have high enough levels to register in a urine sample.

There are some medications that can cause a false positive, most those kinds containing hCG. And about half of all conceptions don't proceed to pregnancy, so there may be chemical 'positives' for a pregnancy that won't progress.

For some urine tests, evaporation may form a line that could be interpreted as a 'positive'. This is why tests have a time limit during which you should examine the results.

So I guess the lesson here is nothing is fool proof. If you think your pregnant, the doctor is your best bet...and even they can be wrong.

Answer 8

they can be inaccurate at times depending on various circumstances. so i guess its always best to have a few done, but its always safest to see a doctor to be sure.  

Answer 9

Hi you can get a false neg but not a false positive.

Answer 10

lol yes they do. So  do Cereal boxes lie to you for the nutritional content

http://ca.answers.yahoo.com/question/ind...

Answer 11

any urine test can give a false reading because there may not be enough hormone to detect in just urine at the time of the test. blood test is always the most accurate! so technically they didn't lie, they just gave a false reading!

Answer 12

Some pregnancy tests aren't always 100% so you can't always go by that, but if you went to the doctor he should have the right answer.

Answer 13

They don't 'lie' as they do not have ulterior motives. But they can sometimes have false readings.

False positives DO happen, they are just rare.

Answer 14

they don't lie sometimes they just give you false answers

Answer 15

I had this to happen. I had an ectopic pregnancy. If you have had this to happen, you need to discuss with your doctor the possibility of an ectopic pregnancy.

Answer 16

A small percentage of them get incorrect results, but I wouldn't say they "lie."

Answer 17

you are deluding yourself.  you are preggers

Answer 18

It's not actually lying it's just that sometimes they have false reading(remember it's electronically generated so there's always room for mistake), that's why you should not always solely depend on pregnancy test you should always go to a doctor

Answer 19

sometimes the hormone can not be detected by the pregnancy test... but a blood test is accurate because its in your blood... it all depends on the woman... in many ways it does make sense!

Answer 20

Usually pregnancy tests are 98% right, and not always 100%. But if you went to the doctors to check, and they say your not pregnant I would get a blood test.

Since the doctors who check for pregnancy don't take blood samples, I'm 100% sure that the blood test will be right.  

Answer 21

They dont 'lie' they can give false readings.

"How Common is False Positive?

Home pregnancy tests are about 97% accurate when the results are read on time and all of the instructions are followed correctly. A false positive could be the result of:

Chemical Interference:

Some drugs contain the pregnancy hormone Human Chorionic Gonadotropin (HCG). If you are taking one of these it can result in a false positive pregnancy test. If you are having infertility treatments and have had a shot of HCG, you should not take a pregnancy test until you are sure the shot is out of your system.

Chemical Pregnancy:

Unfortunately, a chemical pregnancy is the result of an early miscarriage. Because many pregnancy tests are highly sensitive, they can sometimes detect these pregnancies even though they’ve already ended. When this occurs, the woman will get her period as normal. It is estimated that half of all first pregnancies end in miscarriage.

Evaporation Lines:

Not technically a false reading, but a result of user error. A common mistake that women make when reading home pregnancy tests is waiting too long. This could result in a line appearing that could be read as a positive result, but is actually an evaporation line created as the urine on the test dries.

If you’ve taken a home pregnancy test and you have doubts about its accuracy, you should see a doctor for a pregnancy blood test. These tests are more sensitive and can give you an accurate reading just one week to 12 days after conception."

"How common is a false negative pregnancy test and what causes it?

False negative pregnancy tests and what causes them:

If you take a home pregnancy test too early, you may get a false negative result. A false negative result is when the test says you are not pregnant but you are. This can be misleading and when using home pregnancy tests you must be very careful of avoiding any factors that may cause false results.

There could be various reasons for a false negative test.

Early Detection Attempt

One reason for a false negative pregnancy test could be that you took the test too early. Pregnancy tests vary in their sensitivity which means how soon they can detect the hormone Human Chorionic Gonadotropin (hCG) in your urine. It is possible that although your ovum might be fertilized, meaning you may be pregnant, but your body has not started secreting enough Human Chorionic Gonadotropin (hCG) for the test to measure. Your body needs time for the hormone to rise to a high enough level to be detected in a test.

Erratic Technique

There is a possibility that while using the home pregnancy test strip you either did not dip it well or did not hold it well in your urine stream. This error in technique may give false negative results.

Missed Reaction Time

For accuracy in home pregnancy tests it is essential that you read the test results in the stipulated reaction time. If you let the test sit for too long (after the instructions on the box tell you), the test is invalid. This may cause it to show false negative results.

If the home pregnancy test shows negative results but you still think you could be pregnant, wait a few days and try again. A negative result can mean that you are not pregnant, you took the test too early or you took the test wrong. Also, if you have received different answers on multiple pregnancy tests, it is recommended that you get a blood test done to get an accurate answer."

Sorry it's so long!

Answer 22

when you got the test done, your hcg levels were too low in your urine. like maybe your positive was in the morning right when you got up so the urine wasnt diluted. but the longer through the day you wait the urine becomes diluted with water.

Answer 23

They don't always work completely accurately, but I don't think they are intentionally lieing to you.  Mine worked perfectly for me...

Answer 24

There are usually false negatives... But hardly ever false positives... The blood tests are usually 100%... so if you went to the Dr & it was negative, then the Blood was positive, Id say another Dr or have them do another one... Good Luck!

Answer 25

Well, yeah they can give false readings.  Either because the hormones are too low to show positives, or they can show positives when you are not during a "chemical pregnancy"  

Answer 26

There's no such thing as a false positive, generally speaking, but you can get a false negative.

Some pregnancy tests are more sensitive than others so it's possible to get a positive test on one and then a negative test on another taken soon after, assuming it's very early in the pregnancy.

A blood test is far more sensitive than a urine test, so it will be much less likely to give a false negative.

When I got a positive result followed by a negative result, it turned out that I'd had a miscarriage.

Since you've already had a positive result on a home test, just go get the blood test done if you haven't already (and trust that result). If the positive home test was more than a week or so before the negative tests, you may very well have had a miscarriage. If the positive test was a few weeks ago and you haven't had a blood test, you can probably take a new home test and trust the result.

Answer 27

You can get negatives following a positive for a couple reasons:

* Urine is more diluted (either you drank more water, or recently went to the bathroom)

* Test is not as sensitive in measuring the amount of HCG (you can look up the sensitivity of various tests at www.peeonastick.com)

Typically the doctor office tests aren't as sensitive as the "early reader" ones you can get at the store.

What was the blood test result?  The important thing is to make sure your blood level doubles :)

Answer 28

It can happen.  Your hormones change constantly, along with stuff in food, in the environment, any supplements you might be taking--all of these things can affect a pregnancy test.  

The only sure way to know is to go to the dr. and have the blood test done.  

I had a friend who took 5 home pregnancy tests and 4 said she wasn't pregnant, 1 said she was.  And they were all the same tests (made by same company).  So I suggested she go to the dr.  Dr. did blood work, she was pregnant.  So things can happen.  Nothing is 100% all the time.