The rank of blood was the highest family rank a member of a Chiss family could possess. Admiral Ar'alani was born a full-blooded daughter of the Irizi family, until her promotion to a flag officer. Members of the Chiss Defense Force promoted to flag rank or higher (starting at commodore) were stripped of their family status.
With the rank of blood came esteem and privileges within Chiss families. In addition to being granted preferential treatment in family affairs, being blood boosted a Chiss's career prospects as a civilian official of their family.