Over-the-counter pregnancy tests are either digital or dye-based. Both blue and pink dye tests employ a chemical reaction that activates a color change on a designated strip to display a line or plus sign when hCG is detected in urine.
What does it mean if the dye runs on a pregnancy test?
Only urine that contains a sufficient level of hCG can cause the test’s dye to stain in a way that shows a positive result. In early pregnancy, there may be very little hCG in the urine, and the positive line may be faint.
Does line color matter on pregnancy test?
When taking a pregnancy test, any line in the test indication area is considered a positive pregnancy test, even if it is lighter than the control line. The darker line is usually the control line.
Can a faint line be negative?
A very faint line may also occur if the urine is too diluted to detect hCG. Drinking a large amount of fluid can dilute the urine and skew the results. If a faint line becomes a negative test result the second time around, it could be the result of a very early miscarriage in the first few days and weeks of pregnancy.
Do pregnancy tests turn positive after 10 minutes?
The instructions on most pregnancy tests will advise you to read the results within a certain window of time. This usually ranges between a couple of minutes up until 10 minutes later. If you see a positive result beyond this time frame, you may be left second-guessing the results.
Why do you have to wait 3 minutes for a pregnancy test?
The tests ability to detect HCG hormone will be higher allowing an earlier positive result if you are pregnant. Usually the tests recommend waiting about 3 minutes before reading it. If you let the test sit too long the the test may show a false positive result.
Is faint positive at 4 weeks normal?
A very faint line on a pregnancy test usually means that implantation has occurred and you’re in the early stages of pregnancy. But you’ll want to test again a few days or weeks later to see if that line has become thicker and darker, meaning your pregnancy is progressing — and you can safely start getting excited!
How long after a faint positive should I test again?
So, if you do get a faint line, Kirkham recommends waiting two or three days, then testing again. If it’s still faint, she suggests going to your family doctor for a blood test, which can measure the specific amount of beta hCG, to check if the pregnancy is progressing as it should.
How can I check my HCG levels at home?
For some home pregnancy tests, you’ll hold an indicator stick directly in your urine stream until it’s soaked, which should take about 5 seconds. Other kits require that you collect urine in a cup and then dip the indicator stick into the cup to measure the hCG hormone level.
What is a shadow line on pregnancy test?
Evaporation lines are common and can occur with any pregnancy test. An evaporation line is a line that appears in the results window of a pregnancy test as the urine dries. It can leave a faint, colorless line. If you’re not familiar with evaporation lines, you might see this line and think you’re pregnant.