The external QCs shall be analyzed multiple times consecutively (based on the EQAS rules), and t he mean results of the following blood variables (full blood count) shall be returned:  Red Blood Cell (Erythrocyte) Count  RBC  Mean Corpuscular Volume  MCV  Haematocrit  HCT Haemoglobin  HGB  Mean Corpuscular Haemoglobin  MCH  Mean Corpuscular Haemoglobin Concentration  MCHC  White Blood Cell (Leukocyte) Count  WBC  Platelet (Thrombocyte) Count  PLT Reticulocytes Percentage  RET%  Laboratories  or ABP Laboratories  may also participate in ring tests with other laboratories (hospitals, clinics, etc.)