Automated complete blood count (CBC) - UpToDate

This topic reviews the automated complete blood count (CBC), including definitions of the parameters, their clinical significance and relevance, and the methods used to determine these values. Separate topics discuss evaluations of abnormal findings on the CBC and the peripheral blood smear. ● Counts too low • Red blood cells (RBCs) – (See "Approach to the child with anemia" and "Diagnostic approach to anemia in adults".) • Platelets – (See "Approach to the child with unexplained thrombocytopenia" and "Diagnostic approach to thrombocytopenia in adults".) • White blood cells (WBCs) – (See "Evaluation of neutropenia in children and adolescents" and "Approach to the adult with unexplained neutropenia".) • All three – (See "Approach to the adult with pancytopenia".) ● Counts too high • RBCs – (See "Diagnostic approach to the patient with erythrocytosis/polycythemia".) • Platelets – (See "Approach to the patient with thrombocytosis".) • WBCs – (See "Approach to the patient with neutrophilia

This topic reviews the automated complete blood count (CBC), including definitions of the parameters, their clinical significance and relevance, and the methods used to determine these values. Separate topics discuss evaluations of abnormal findings on the CBC and the peripheral blood smear. ● Counts too low • Red blood cells (RBCs) – (See "Approach to the child with anemia" and "Diagnostic approach to anemia in adults".) • Platelets – (See "Approach to the child with unexplained thrombocytopenia" and "Diagnostic approach to thrombocytopenia in adults".) • White blood cells (WBCs) – (See "Eval