General In vitro diagnostics tests are the general core and routine laboratory tests for clinical chemistry, haematology, blood transfusion, microbiology (virology, bacteriology, parasitology and mycology) and histopathology. These tests were selected on the basis of the scientific validity of an analyte, i.e. the association between an analyte and a clinical condition or physiological state; and clinical utility. Many of these tests are required for effective management of patients and have already been described in WHO publications.