I'm afraid I may have tetanus, are there any medical blood test that can verify the infection?

Yes. What is the difference of being afraid of having a potentially fatal disease and getting checked out and treated?
You don't. Tetanus is obvious clinically. You will know that something is terribly wrong. It is not at all subtle. If you've maintained your immunizations, it's unlikely. And nowadays, it's survivable.
No blood test. The diagnosis of tetanus is clinical . Based on history , symptoms and exam. The only way to be sure is to consult with a doctor.
No tetanus test. If you asking, you probably do not have tetanus. It is a clinical diagnosis, no lab tests are diagnostic. A common finding is lockjaw, and muscle spasms.