In addition to the various red cell membrane antigens that have been assigned to
blood group systems there are antigens that await final assignment, if ever. There are
indications that some of these antigens may belong together yet little or no indications
have been given for others. To further organize the antigens for a systematic
investigation and to eliminate duplication, the ISBT Working Party for Red Cell Surface
Antigens has recommended that these be included into groups called collections and series.
The number of collections existent at any one time depend upon the information that is
presently available. The antigens within the various collections
have serological, biochemical and genetic relationship but do not fulfill a criteria for system status.
These blood group antigens appear to be unique unto themselves. They are further subdivide into two groups
This is a group of red cell antigens that occur in less than 1% of most populations
studied and are not known to belong to a blood group system.
This is a group of red cell antigens that occur in more than 90% of the population and
are not known to belong to a blood group system.