How to prove im American Indian w/o legal documentation

So im 21 (just turned) and im trying to figure out how to prove that im my biological fathers child without having legal documentation saying that I am his child. My biological father is American indian and so is both his mother and father. I don’t know the percentage for myself because i don’t know much about my biological fathers side of the family. Is there any way i could do paternal blood testing to substitute the birth certificate? My step father who adopted me when I was 6 is on my birth certificate and I refuse to change the names.
Is there any way i can still qualify? I am American Indian and i know it, it’s just i don’t know how to legally prove it.

Confirming biological parentage is only the 1st step. Most schools will require that you be formally registered w a tribe.

Is your birth father a tribal member? Maybe if you combine his tribal membership with a paternity test, it might work.
It seems worth a try:

For purposes of the tuition waiver, Native American is defined as follows:
“The term Native American shall include all persons of Native American descent who are members of any recognized Native American tribe now under federal jurisdiction, and all persons who are descendants of such members who were, on June 1, 1934, residing within the present boundaries of any Native American reservation, and shall further include all persons of one-half or more Native American blood. Eskimos and other aboriginal people of Alaska shall be considered Native Americans.”

This is important for you to look into, as under ObamaCare, Native Americans can get subsidized health insurance coverage, with higher than normal benefits (copays and deductible waivers). For tuition purposes, perhaps the school will accept documentation from your state’s health insurance exchange

Wait…the OP is saying that he had no documentation that this Native American person is really his dad.

So…start with step number one. You need proof that this person is your father. Without that info it really doesn’t matter what his lineage is. You need proof that he is your father.

Are you in contact with your father? Would he submit to a paternity test?

Your father’s tribe should be able to advise you on what you need to do in order to be recognized by them, and if it is even possible.

I have a colleague who is not Native American, and who is an adoptive parent of two enrolled members of a tribe in our part of the US. Whether your father’s tribe would recognize you may be another story entirely.

Would your biological paternal grandparents be willing to help you? Do you have contact with them? Would they be willing to attest to the relationship?