You can take a blood test that may establish the probability of your Native American ancestry. If you can identify each of your parent's quantum (or percentage) of non-Native American blood, you can also find your own percentage (or quantum) of non-Native American heritage using a Quantum Calculation Chart. Both methods have limitations.

Genetic testing has been a hot topic for a few years now, and widely publicized accounts of celebrities who've discovered famous ancestors or specific tribal identifications have made genetic testing popular – but some some specific claims by the companies offering to use your DNA to find out where you came from have been criticized for over-promising.

There's no doubt that DNA tests can give you useful genealogical information, but as scientist Deborah Bolnick cautioned in a review of these claims in Science, specific tribal identifications are likely unreliable. Similarly, you can find out a lot about your American Indian heritage with one of the several DNA tests offered online by MyHeritage.com and others, but not your specific percentage of American Indian blood.

All these DNA testing sites have similar requirements. Basically, you use a swab to sample your saliva and send it to the testing site.

The only way to accurately determine specific genetic details – your tribal ancestors and your percentage of Indian heritage – is to create or have created a genealogy chart that identifies with 100 percent certainty each ancestor by name and Native American tribal affiliation,.

How far back you need to trace your genealogy depends on how accurate you want the results to be. Perhaps, for instance, that you've traced back three generations and have established the Native American identities of each ancestor. Each of your eight grandparents has contributed 12.5 percent of your DNA. Going back one more generation, each of your 16 great-grandparents has contributed 6.25 percent.

If seven of those great-grandparents were Native American and one was not, your percentage of Native American ancestry would be 94.75 percent. To put it another way, the difference between all eight great grandparents being Native American and seven of eight being Native American is only 6.26 percent – for most purposes not a significant difference in ancestry . Going back three generations of ancestors is probably sufficient.

If you create a family-tree chart yourself, or pay a company to create one for you, you can use it to find your percentage or quantum of Native American blood using a chart like that provided by Ancestry.com. If, for example, you have one parent with a quantum of 1/4 non- Native American ancestry and another whose quantum of non-Native American ancestry is 3/8ths non-Native American, using the chart you can conclude that your quantum of non- Native American ancestry is 5/16ths.

DNA tests and genealogy charts are useful in establishing the probability of your Native American heritage, but just as DNA testing has limitations, so does genealogy research to create your family tree. The calculation itself is exact, but in the real world, the actual quantums of non-Native American ancestry for 19th C. great-grandparents can't be known with complete certainty. Europeans, African Americans and Native Americans have been living together in America for centuries and, historically speaking, families are particularly not forthcoming about interracial unions.

What you can say is that using either of the two described methods or both together, you'll know more about your Native American heritage than you know now.