Pregnancy 21 days through the urine pregnancy test and blood HCG test can help to confirm the diagnosis, commonly used test methods are as follows: 1, urine pregnancy test: you can through the early pregnancy test paper or pregnancy stick test morning urine to detect pregnancy, pregnancy about 10 days after the pregnant woman will be excreted in the urine of a kind of human chorionic gonadotropin, at this time to take the urine test, if it is positive, it can be diagnosed as pregnancy; 2, blood HCG test: Women with normal menstrual cycle, 21-24 days pregnant can do HCG test, blood HCG test method is to check the value of HCG in the blood through blood sampling, more accurate than checking the HCG in the urine, blood HCG to facilitate dynamic observation and review, so that the objectivity of the quantitative indicators is better. If you have an abdominal ultrasound, you will need to be at least 6 weeks pregnant before you can see the gestational sac. Ultrasound can determine the gestational week of pregnancy, and can also rule out ectopic pregnancy. If the menstrual cycle is irregular, in some cases it takes up to 40 days, or even 50 days, to detect the pregnancy, which is related to the delayed conception of the individual and the later formation of the fertilized egg.