Rare blood types in the Asia Pacific region.

Rare blood types are generally defined as those that occur at a frequency of 1 : 1000 or less. However, some rare blood types have much different frequencies in global regions or specific ethnic groups. This review explores rare blood types in the following categories: rare blood types that lack high-frequency antigens and where to find them, rare blood types that express low-frequency antigens, rare blood types with higher or lower frequencies in the Asia Pacific region and rare blood types that are difficult to find in the Asia Pacific region but are provided by the JRC. In addition, the study of rare blood types has revealed clinical correlations with disease states and resistance to infections. [ABSTRACT FROM AUTHOR]