Can You Cause A False Positive HPT

16 Replies
mg - January 11

I took several HPT and got both positives and negatives. My question is after you place urine on the test and it runs completely across, the control line shows up ect, if you then you take the test apart to look at the strip (we all do this), can this cause a false positive to show up? I have heard that it can becouse as the dye finishes drying the color can stick to where the positive would be. But I have also heard that the ONLY thing that can cause the line to turn pink is the presence of HCG. I just dont know.


DM - January 11

mg, false positives are verrry rare. In fact most of what I have read has stated they are almost impossible as the only way to get a positive is for the test to detect the HCG hormone... I think what you are seeing is a evaporation line. I personally haven't taken the tests apart, but I have checked a test the following day after it was neg, and found it was showing "pos" ... however, it was an evap line.... and taking the test apart surley must cause it to dry out faster therefore producing that evap line to appear.


mg - January 11

I just dont know, the urine runs completely across and finishes, and within 8-10 minutes a second pink line appears. It could be an evaporation line except that it is very very pink, and the only other thing that makes me wonder is that I have taken numerous tests apart and none have had a pink line. I guess I will just wait it out a day or so.


Deb - January 11

I had two false positives with first response early test. I don't trust them at all. Plus, after the alloted time, sometimes they look like positives but they are evap lines as the others have said. You can visit for more info on this subject.


mg - January 12

I took a HPT that I got from a friend in the ER it tests at 20Mui, yesterday there was really nothing on it, but today it has the faintest line, but I can see something. This test does not have a window, so it is exposed to air all the time. I am just going to watch it for a day or two. If I am it will get darker, if not I will get AF.


Patti - January 12

mg, pregnancy tests cannot be read after 10 minutes. You can get an evaporation line that is a false positive. Can you get more tests from your friend? I would wait and test with first morning urnine tomorrow. Best of luck to you!!!!


Emily - January 12

mg mostly false pos are rare, If you take a test apart and you then get a line and you aren't pregnant, then you most likely are seeing an avap line, not a pos line. check out the questiona nd answer section. she explains it all very well in plain english...also like it have been mentioned don't read a test after teh alotted time frame. normally after 10 mins. the gal from peeonastick does not believe in false pos and she explains why, but to each his own. I have never had one but did have an evap line once. Evap lines are not false pos.


Patti - January 12

Emily, you're right. I didn't mean an evap line was a false positive, but that people read an evap line and falsely think it's a positive.


krob - January 12

also to note evap lines are very faint and are not usually greyish not pinkish or bluish when in doubt retest


mg - January 12

The test instructions said for low amounts read the test after 10 minutes. The other tests were read before 10 minutes were up. The lines were very pink not grey, except for the ER test, but that one uses black ink for the test. Who knows maybe they are evap lines, I guess I will know either way soon enough.


Emily - January 12

I say wait a few days and test again. Good luck! (Pattie just wanted to clarify for everyone that evap lines are not false pos, but like you said a lot of people read them that way) MG your lines should be getting darker. plus all tests are diff so if you took 2 diff (even the same brand) you could get one neg and one pos depending on how much the test will detect. Some will detect a lot lower than they claim. Aslo it depends on when you took the test. If you took one int hte am after holding your urine, it woudl have more hormone than one you took later after having something to drink, (it would dilute your uine and less hormone would be present)


SweetP - January 12

Okay, so sorry mg that you're going thru all the ups and downs of trying to interpret the tests! BUT, you shouldn't take the test apart because sometimes the dye does collect in the test line because of the antibodies that the tests are made with. Second, you should NOT read the test after 10 minutes, especially if its a blue dye test because most tests will develop some sort of line after a few hours and this is so unreliable. If i were you I'd just test again in a day or so, don't take the test apart!! Put the test on the counter and walk away from it. Ten minutes come back and read it, put it up to a window if you want, but don't take it apart. After 10 minutes (at the most!) you'll have your answer. If you're unsure, THEN you can take the test apart, but definately not before the 10 minutes its up. That can cause false negatives and false positives, again, because of the reacting character of the antibodies in the test itsself. Hope this helped some!


SweetP - January 12

Sorry, I forgot to say that I hope you get a BFP when you do test again! I also wouldn't get First Response as I always get some sort of line on those, unless you use two tests at once to cross-check each other. Please let us know how it turns out!


mg - January 13

Well this is strange, I am not due for my AF for 4 days, today I started AF, but it was much lighter then normal, and I had more upper AB cramps rather then the normal lower. But here is the strangest part, I started this morning and by 6pm I have already stopped bleeding. Very abnormal for me. Maybe I am just stressed.


Cindy Johnson - January 15

They say you shouldn't read them after 10 minutes. I wouldn't consider it a positive unless the lines show up right away or after like 3 minutes. I don't want to sound neg. , but that is just what I have read. :( Sorry!! -Cindy


indobray - January 15

I took a hpt one morning and it was negative, I put it in the garbage. I started my af that day. Later that night, I took the hpt out of the garbage and looked at it again and it was positive. I didn't take the test apart or alter it in anyway. I am not pregnant.


oz - January 15

It may be because you stressed that your af started then stopped as you said. If it doesnt start back up i would go to the dr and take a test there that way they can read it for you and confirm either way. Goodluck xx



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