Pregnancy Test Faint Lines and Evaporation Lines

The Two Big Pregnancy Test Questions:
1) How Early Can I Test for Pregnancy?
2) What Does a Faint Line Mean on a Pregnancy Test?

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How Early Can I Test for Pregnancy?
One question women frequently ask when trying to conceive is: How long do I have to wait before I can take a pregnancy test? Though hCG is produced at different rates in different women, there are general timelines for deciding when to test. However, when testing on the early side, do not rely on one test for conclusive results - especially a negative result: the hCG threshold for displaying a positive result on a home pregnancy test may not yet have been reached.
 
Early Detection Pregnancy Tests
 
When a woman becomes pregnant, the amount of hCG in her system should be around 25 mIU at 10 dpo (days past ovulation), 50 mIU at 12 dpo, 100 mIU at around two weeks dpo (these are averages that may deviate among different women). Test sensitivity equates with early-detection - and the lower the number, the sooner a test can detect pregnancy. At 20 MIU test sensitivity, you can begin testing at 7-10 days post ovulation, though the earlier you begin testing, the higher chance you have of getting a false negative. Early-Pregnancy-Tests.com carries early-detection pregnancy tests capable of detecting just 20 miu/ml hcg.
 
Here, implantation of the fertilized egg needs to take place before hCG is produced by the developing placenta, and that generally occurs at 6-10 dpo. If you decide to test early, make sure you perform a few follow-up tests every other day using first morning urine. Your hCG levels should rise exponentially, doubling every 2 days - which means that the follow up tests should eventually detect pregnancy if you are, in fact, pregnant.

For earliest detection of pregnancy, use first morning urine, as this urine sample contains the most concentrated amount of hCG. If using first morning urine is not feasible, avoiding urination for several hours before using a pregnancy test.
 Faint Line
A faint color band in the test area of a pregnancy test indicates, in most circumstances, a positive result for pregnancy.
However, a faint line appearing after the designated reaction time of the test may be an "evaporation line".
What Does a Faint Line Mean on a Pregnancy Test?
On a pregnancy test, a faint test line - or color band - is usually indicative of a positive result, as long as it's read within the time frame - or reaction time of the test (usually at 5-10 minutes). If you perform the pregnancy test properly and read results within the recommended time frame, then a faint or weak color band in the test area is very likely a positive pregnancy test.

Evaporation Lines
Evaporation lines, however, can confound results if tests are not interpreted within the clinically recommended time frame. An evaporation line develops when the urine on the test area begins to dry, leaving a faint, usually colorless line. Evaporation lines appear to show up (or not show up) as a result of the composition of the particular urine specimen - and they may appear on any test regardless of brand.

Explanations for Faint Positives
  • Testing Too Early: If you test too soon, hCG may not be at a sufficient level for test detection. See the section above on determining when to take a pregnancy test.

  • Low Test Sensitivity: Different tests detect hCG at different levels, from 20MIU to 100MIU or more. 20 MIU tests will display a faint line when when hCG levels are at 20 MIU, while less sensitive tests will display a negative result. At 50 MIU levels, a 20 MIU test will show a stronger color band while a 50 MIU test will show a very faint band.

  • Dilution of Urine Specimen: Urine specimens may be diluted due to frequent urination or consumption of liquids. First morning urine is recommended for pregnancy testing as it contains the most concentrated presence of hCG.

  • Chemical pregnancy: Sometimes an early pregnancy is detected - followed by negative test results. A chemical pregnancy means implantation takes place (hCG is produced for a short time) followed by a miscarriage (generally, before any other pregnancy symptoms are detected).

  • Evaporation Lines: Always read your test results within the test reaction time (usually 5 minutes) as evaporation lines can develop as the urine dries on the test area. Evaporation lines appear to show up (or not show up) as a result of the composition of the particular urine specimen - and they may appear on any test regardless of brand.
Remember, a pregnancy test does not function like "light switch" - and just turn on: different hCG levels will produce different gradients of color bands (from very light, faint lines early in pregnancy to dark, rich color lines later on as hCG develops).
Read More About Pregnancy Tests
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Comments

I took the first morning urine and the control line showed immediately and then what looks like an evaporation line appeared immediately after. Did I use too much urine?

Ol Iam 5 days late so I took a test and no lines what dose this mean

i had missed my period and gone for a pregnancy test by HCG kit.
1 clear pink line appear in the kit with no another parallel line (means no two parallel vertical lines) instead of that there was a pink line perpendiculer to it and i have done the test at night. what does it mean?

I am 17. My boyfriend came inside me a lot because he and I have been trying to concieve for about a month. My period came last month and we tried for the first time about a week after my period and ever since then. Two nights ago I took a pregnancy test but I didn't pee on it enough to get a result right away. the next day, his mom wanted me to test again so she pulled out the test I tried on the previous night (but couldn't because I did not get a lot of pee on it) and when she pulled it out, there was a positive result. I took another test and the result was negative at first and then turned positive after an hour.. I don't know whats going on.. I've been having the symptoms of pregnancy but maybe its too early to check.

Hi Id like to ask a question. I did three pregnancy tests. All turned out positive and i was suppose to get my period at that time. Then i did a blood test the same day i got my period. It turned out low positive HCG 302.9. Then i waited to do an echo so while my period is still lasting i did the echo and there was nothing. The same day i did a pregnancy test and it showed positive. Now for the first time in a long time i have been bleeding for 11 days ( some days very little like ending others like the first day) What should i do?

By the way, I am critically aware of the intense emotions involved in some people when they are hoping or trying to become pregnant - and I hate to think of the emotional heartache and anxieties that these mixed or uncertain test-results can cause - hence why I sat and wrote the article. Hope it helps, and feedback - whether positive or otherwise - is always useful. Take care - and lots of baby-dust - to all prospective Mums-n-Dads Smile

Hello everyone Smile I get really annoyed when I read all these articles and comments about 'evaporation lines' on home pregnancy tests, and especially, when such comments or articles are said to be written by so-called 'experts' or 'clinicians', and which seem to leave a large number of women with all sorts of doubts and anxieties about test-results. So I thought I would sit and write a few facts about various similar tests. I am a clinician and I also have much experience using various tests within laboratories or clinical settings. I have also been trained in the medical micro-biology (lab-testing). The home pregnancy tests are 'assay' tests which rely on specific reactions between chemicals, to produce coloured lines. The 'control' lines of the home pregnancy tests are assayed areas which are designed to react with specific chemicals commonly found in urine, and which, when detected, react with the chemicals in the control-line assays (strips/areas) and turn them a certain colour (pink or blue depending on the test used). However, the 'pregnancy' assay (test -area/strip) is designed to change colour only if it comes into contact with the HCG hormone – the 'pregnancy' hormone. HCG is only produced when an egg has been fertilised. So then, if no conception has occurred, then no HCG will be produced by the body, and therefore, no HCG will ever be found in the urine. Moving on... sometimes fertilisation occurs and HCG is produced for a while, but for some reason, the body detects that the pregnancy will not be successful (not 'viable') and the fertilised egg ceases to continue to divide and develop. So the pregnancy stops. However, until the pregnancy stops, the woman will still be producing HCG, and may well have some of the other 'usual' symptoms of pregnancy (though some women have absolutely no symptoms for a considerable period of time), and; although the pregnancy may have stopped almost as soon as it began; it may still take a couple weeks or so for all the HCG in the body to be disposed-of via the urinary system. Also, it may still take a couple weeks or so for the 'symptoms of pregnancy' to stop altogether. This process of fertilisation, followed by a very early termination is known as a 'chemical pregnancy', and many women can have these, whereby the woman is sure she is pregnant, but then she later has a period – even though a home pregnancy test might have shown a faint or clear line in the first couple weeks or so – and hence is why some women are left wondering why their period returned. So for those women whereby, unfortunately, fertilisation has occurred, but the pregnancy was not viable, they were pregnant, but the pregnancy stopped. However, for those women whose egg(Drunk is fertilised, and for whom the pregnancy continues, then they will continue to produce HCG from the moment of fertilisation, and, those levels of HCG will rise over the coming weeks, and will, at some stage, be readily detectable either by home pregnancy tests, or by blood tests via their local Doctor or Clinic. So then, back to home pregnancy tests ….. I have already said that the control lines react to molecules found within normal urine, and, when those molecules pass over those control-line areas (control 'assay' areas) then the molecules come into contact with other molecules within the control assay and they bind together. Indeed, they are attracted to each other by a process known as 'chemotaxis'. And on contact, two different molecules form a 'complex' which changes both it's shape and it's colour – hence the coloured control lines you see in the test areas. However, if the right molecules are not present in the urine, then no other molecules can bind to the control molecules – and no colouration will occur – so the test will be 'void' – and another test should be done. However, in the event of carrying out a test – and the control lines change colour as they should, then the woman or couple is anxiously waiting (if they wish to have a baby that is) for the 'positive' or 'pregnancy' line to change colour too! And here is where we need to get onto the subject of the 'faint' lines and the 'evaporation' lines that people keep talking about. Going back to the test-strip; the 'pregnancy' line contains different molecules to the molecules of the 'control' lines; and the molecules in the pregnancy line/strip (the pregnancy test-assay) will only react – and change colour – in the presence of one other molecule; and that is the HCG hormone. No other molecule or hormone will cause it to change colour. Changing the subject slightly, if we take a pure white tissue and add one drop of water onto it, the area of the tissue containing the water will now have turned slightly 'grey' – because it's wet. But it wont turn pink or blue. So if we carry out a home pregnancy test and the control lines are pink or blue (depending on the test you use), but the 'pregnancy' strip remains white or slightly grey – even hours after the test – then there has been no HCG detected in the urine, to mix with the pregnancy-strip molecules and to make them change colour (which is what you will be hoping for). So if the strip remains white or slightly grey – no matter how many hours or days after you did the test - then the strip is simply wet from the urine, but it does not contain any HCG. So, either you are not pregnant, or, if your period has stopped, then you may still be pregnant but your HCG is so low that it cannot yet be detected by the test. However, if you do a test and you get the faintest coloured line in the 'pregnancy' test-strip/assay area on the test, then HCG has definitely been detected. If it's faint, then HCG is present in very low concentration, and if it is dark coloured line, then the concentrations of HCG are higher. But whatever the concentrations, provided you get a colour in he 'pregnancy' area, then you are pregnant at the time of testing. And now for the famous 'evaporation lines' that so many people – and 'experts' talk about. To start-with, no evaporation line will be coloured (pink or blue etc. depending on the test you used). Only the HCG can combine with the pregnancy-assay molecules and bring about a colour-change. So if the line is coloured – no matter how faint the line is – then HCG made the line change colour – nothing else! However, just like the wet tissue-paper we talked about earlier, if the area is simply wet with urine, the pregnancy strip may possibly turn a little 'grey' – like a 'shadowy' colour; but if there is no pink or blue colour, then no HCG has been detected. However, remember that the area of the test-stick that you 'wee' on is made of a very dense material, and urine will be absorbed by this dense material and will travel along the test-stick by 'passive-diffusion'. And liquids like to move from an area of their high concentration – to an area of their low concentration, so, because the test-stick is sealed and dry, the urine will travel along it – to it's other end – and may 'drip-out' inside the sealed area of the stick (the bit after he test and control areas that you cannot see). O the urine keeps moving until the end that you 'wee'd' on has no more urine to offer! Then the 'diffusion' will stop. And in most cases, test-sticks – especially those with caps on – can stay wet for days! So if you go back to the stick an hour, or two, or three or four etc after the test; and the 'pregnancy' strip has changed colour (pink or blue depending on the test etc), then, whilst the urine has spent several hours travelling up the stick from one end to it's other, urine has been passing over the 'pregnancy' area all the while. Therefore, even if the HCG levels are virtually undetectable (but present n minute quantities), as the urine travels over the pregnancy-assay, the HCG will still be attracted-to (remember the 'chemotaxis' we talked about earlier) and will bind with the molecules in the pregnancy-assay – hence a positive coloured line showing up to several hours after the test was done. Like I said, no other molecule or hormone will make the pregnancy-assay change colour – except HCG. So, if after an hour, or several hours, you have a coloured line in any way, then HCG has been detected – and HCG can only be found in your urine if an egg has been fertilised. So let's not have any more if this 'evaporation line' confusion. If it's slightly grey or remains white – however long after the test you look - then no HCG is present. But if it 's coloured – then HCG is present – in whatever concentration – because only HCG can bring about the colouration of pink/blue, depending on the test you are using. And finally, some tests don't dry out for days – sometimes many days - (especially those that you put the caps back on), so the water-content of the urea has not even evaporated – yet people still go on about 'evaporation lines' – which, in my opinion is nonsense. And for the record, my Wife's test had a coloured line several hours after we did the test – and I knew she was pregnant – despite the articles I read on the internet about evaporation lines. And indeed, the next tests proved that she was.

I'm 5 days late a took a pregnancy test yesterday and it came back a very very faint line showing negative... I'm not sure what this means it was so faint I had to hold it up to the light..

Anonymous- jan.12,2013

My husband and I went off birth control about 7 months ago. Not trying to concieve, just letting nature take its course. My periods are very abnormal. Cycles ranging anywhere from 28-40 days apart. 40 days has only been once, and that was a few months ago. Today is day 43 and still no period. I took a dollar tree test this morning and a very, very faint line showed up within i'd say about 3-5 min. But I am curious if it is a evap line? I am not too educated with this. I am nervous to tell my husband just incase I'm not. Don't want our hopes up for nothing. I'll prob test in a few days again

I had unprotected sex 2 days before my period started. It lasted 4 days. I went to the dollar store and bought a test. If it was positive it would of had 2 lines in both windows but mine had a line in the window showing it was done and the window used for the result turned alittle pink but not a line. I was confusied so I went to the grosey store and bought a better oneand the same thing happened. Just a little colored dot in the result
window. Am I or not? If any bit of color shows up line or dot is that possitive

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