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Detecting evaporation lines
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by bioclock1, May 04, 2008
How do you know if you're looking at an EVAP line or a delayed BFP??? I took 2 EPTs and 2 Equates (all tests were +/-)  These tests were all taken within 4 days of each other. The most recent two (one of each) had thin linear (going up and down) lines making a faint + sign. The oldest two (one of each) didn't have any evap lines.
Do evap lines disappear...which is maybe why the oldest tests didn't have any extra + line and the most recent two (different brands) did?
When women get faint positives is the line thick (on plus/minus tests) or can it be thin?
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Member Comments (23)
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by StressHead, May 04, 2008
A line is a line, evap lines are very rare especially so many. I would say repeat the test in a couple of days and it should be darker. Good luck!!!
How many DPO are you??
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by bioclock1, May 04, 2008
would be about 7 weeks on tuesday. stil haven't gotten a BFP or a faint positive and I took a test strip test today and it was negative. But I found it weird that 1 ept and 1 equate had an evap line (very thin) and the other two didn't!
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by StressHead, May 04, 2008
I would still wait two days and test again because if you are pregnant and it almost showed today then it should show darker soon. Can you go for a blood test?? All the tests I have taken that were negative were blatantly blank with no room for confusion.
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by ziggysgrl0724, May 04, 2008
Well, usually the difference between a faint BFP and an evap line is the time it takes to show up.  If you can only see the line after the suggested time limit on the HPT then it is prob a evap line...if the line showed up before the suggested time it is probably a faint BFP....I have never seen an evap line on a HPT before, but I did get a few bfp that were barely visible.  You said you got a faint line on an equate, well I did too, and i have the picture of it...this was from 10 or 11 DPO and it was a positive result, not an evap line...im 20 weeks now.... so you can see if yours kinda looks like this. Good luck!
You should just have to copy and paste the link

http://i256.photobucket.com/albums/hh190/coyotesfan99/stick.jpg
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by bioclock1, May 04, 2008
thanks ladies. I just want to clear the air and say that today when I saw those lines the tests were from at least 3 or 4 days ago...i didn't take the tests today. So the lines proabably WERE evap lines...I just didn't understand how 2 tests could have them and 2 others didnt. how does that happen?
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by bioclock1, May 04, 2008
WOW! congratulations!!! I saw the pic...my equate looks like that but isn't as obvious and the line is more to the right so it's gotta be an evap! But yours is def BFP yea you!!!!
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by ziggysgrl0724, May 04, 2008
oh...if you took the tests that long ago and just NOW saw the lines they are EVAP lines....this is from Peeonastick.com


What's an evaporation line? Evaporation ("evap") lines result with the test's antibody strip just looks slightly different than the space around it. There is a line of antibodies (usually made from mouse cells) in the Control and Test section. The Control line binds with any liquid and turns pink (or blue, in tests using blue dye.) The Test/Result line turns pink only if pregnancy hormone is detected. If not, the moisture passes over this strip and does not turn pink. It may, however, become more visible when the light hits the moisture on the strip-- it may appear gray, colorless, like a "dent" in the test, or like a "ghost line." It may appear at any time-- as soon as the urine hits it, after a few minutes as the test absorbs the moisture, or after the 10-minute time limit. It may appear when the test is drying, or after it has dried. It may disappear as the test is drying, or after the test has dried, or not disappear at all.

The simple fact is that there is always "something there" that is slightly visible-- it's simply the antibodies on the test that would turn pink in the presence of hCG. When the test becomes wet, or as it dries, or after it dries, the antibody strip may become more visible. Therefore, all tests may have them. It is not a defect; it's just how tests are made.

A real positive is identified by its color (pink or blue, whatever the color of the test's dye is) and its appearance within 10 minutes of urinating on the stick. A line that appears after 10 minutes, regardless of color, must be considered an evap line and is caused by the test's chemicals changing. HPT's are rapid assay diagnostics, which means any results appearing after the "rapid" time limit of 10 minutes are invalid.

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by bioclock1, May 04, 2008
actually...i just double checked...it looks the exact same way but again, i didn't see that within the normal time frame and in fact didn't see it until today and I think I took that equate on WEd or Thurs
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by bioclock1, May 04, 2008
thanks for the info. that helps. The line is pink but obviously b/c of time constraint is a evap line!! Thanks for pasting that for me!!! congrats again on your pregnancy!!