There are a total of about 10 variations of type A blood. The most common is A2 (the majority, 90% of A's being A1), though there are also variations labeled "A-x" and "A-Bantu" which are occasionally seen in Africans. These minor variations may have been reactions to malaria and other parasitic diseases of the blood found in North Africa.
Not much is done with the distinction in conventional medicine, as you can transfuse A1 into A2 and vice versa. A2 is found most commonly in Scandinavians, and so pops up a lot in Swedes, some English, Danes, etc. As it apparently developed from A's migratng to colder climate, it seems to be a more complete adaptation to fish in the diet, and perhaps meat. BTW A's AND AB's can be either A1 or A2, hence if you are AB you can be a A2B or an A1B.
Testing for A2 is easy, but not commonly done. After determining that the blood is type A, a separate sample is mixed with a reagent called "A2 lectin" (Dolichos biflorens). If the A slide agglutinates with this, it is A2. This demonstrates the incredible specificity of certain lectins; not only can they agglutinate one blood type over another, they can often agglutinate one subtype of a blood type over another!
Some A's say they feel better after protein, yet I believe that they are still essentially out of balance until they can function as well without it.