Some people on other internet boards claim that blood testing for secretor status is superior to the saliva test. Is that true?
Dr. D'Adamo had this to say about differences in secretor testing:
"Having done 5000 Lewis typing tests in the clinic over the last 15 years, and about 400 salivary inhibition studies, I can safely say that saliva testing is more accurate than blood. The reason being that the agglutinations that are used to determine Lewis types are very delicate (weak antibody reaction) and can easily be misinterpreted, unlike ABO which makes a big glop that you cannot miss (strong antibody). I've even seen conflicting results from two different MedPath labs, especially if the staff is not trained well enough."
Blood and secretor typing is discussed in great detail in this article: Blood Grouping Systems and Typing Techniques