Will marijuana show on my blood test that I'm going to have next week?
Yes, it will very likely show up on your blood test.
You're probably going to have to declare yourself as a smoker, or plan on being denied life insurance for lying on the application.
Also, if they do find marijuana in your system they will likely deny you for life insurance coverage.
However, if you live in a jurisdiction where prescription/medicinal marijuana is legal, and you have a legal prescription for it, then you might be approved by some life insurance companies.
In addition, there is a life insurance company that offers term life insurance no blood tests required. You may be able to qualify for up to $350,000 of life insurance with no exam and no blood testing.