Found this on the net- quite interesting read.- so it must be a cp?
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 a dark coloured line, then the concentration of HCG is 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