A deep and light pregnancy test indicates a high probability of pregnancy. However, to differentiate between intrauterine pregnancy, ectopic pregnancy, or biochemical pregnancy, a blood test for HCG should be taken, and depending on the value of the blood HCG, another blood test should be taken every other day to see if it doubles from the original one. If the HCG doubles from the original level, it is very likely that the pregnancy is intrauterine. If it rises only a little, the possibility of ectopic pregnancy should be ruled out. If it does not rise, but falls, it is likely to be a biochemical pregnancy clinically. Therefore, when a pregnancy test is found to be dark and light, the next step is to take a blood test to determine whether the pregnancy is intrauterine or ectopic, or a biochemical pregnancy.