Question about PT & HCG PLEASE HEP

This maybe a dumb question but the lighter the lines are on a pregnancy test means be less HCG levels right? So is that concerning? Do you just keep testing and making sure that the line gets darker? While your waiting for your dr appt? Or at least till you get a dark line? I've never had a positive and I'm just now reading how you have to have a certain amount of hCG levels in your blood that tell you that you really are pregnant or if you've had a miscarriage/ectopic pregnancy/problems with growth.