My wife has missed her periods its been 1 week . And I have done a blood test in that report say ( HCG - BETA : NOT DETECTABLE ). Please help me out with this what does it means .does she is pregnant or not.

It is only one week and you are probably testing too early. You mean the doctor has done a blood test, right ? Blood tests are usually the most accurate way, but it appears to be saying there are no signs of pregnancy, no apparent change in HCG levels, which change would indicate pregnancy. It is too early for testing.