During performing routine blood test among members of a family, abnormally high potassium values was noticed. Which hematological anomaly is known to cause such a finding?

Hereditary elliptocytosis is autosomal domiantly inherited and runs in families. It is usually asymptomatic and detected during blood tests as it can produce pseudohyperkalemia. Ref: Harrisons principles of internal medicine, 18th edition, Page 876.