[Ubiquitous and rare blood group related antigens and their significance in serology].

The present classification of some factors which are counted among the ubiquitary private and familiar as well as the rare and rarest antigens is shown. The classification of these antigens is often difficult. The distinguishing and systematisation of rare and rarest antigens requires of the investigator much consistency, responsibility and consideration as well as universal calmness so as not to bring too much confusion into an already broad palete of private and familiar antigens. Some antigens are frequently rearranged into already existing systems or even become independent. The authors boldly point out the variants of the ABO and Rh systems in which we meet with some ever so rare antigens, but which, as we know, are nevertheless not counted among the rare, in the sense of present comprehension. The practical value is pointed out and the need of improving our knowledge of ubiquitary, rare, familiar and private antigens in order to be able to master certain complications which these antigens would provoke in serology. In difficulties it is necessary to consult an experienced specialist in a well organised laboratory which possesses several different and reliable serums, the erythrocyte tests and a lot of experience.