A CBC won't tell you if you are or are not pregnant. Period. It measures white blood cell counts, red blood cell counts, hemoglobin among other things. You will have to have a pregnancy test to determine whether you are or not.
There is a possibility that the CBC test will indicate that you are pregnant, though there is no guarantee about this. The CBC test is appropriate because it helps in determining if the patient is anemic or has a low platelet count. The test is important because the pregnant woman may lose a lot of blood upon delivery, which is dangerous for both the mother and baby. Visit pregnancy.familyeducation.com.