noun
MN blood type
A blood group classification based on the presence of M and N antigens on red blood cells, distinct from the ABO and Rh systems.
MN式血液型は、M型、N型、MN型の3つに分類される。
The MN blood type is classified into three types: M, N, and MN.
From English 'MN blood type', where M and N refer to the antigens discovered by Landsteiner and Levine in 1927.