As other people have pointed out, biological passports track markers across time. If you suddenly recieved a transfusion of your own blood it would be obvious from the sudden increase.
But that's discussed in the article as well. Hb levels vary within an individual as well. Timing the transfusion so that Hb levels return to within "normal" physiological range (which is quite wide) would not be detectable and would not disqualify.