• leukaemia;
  • immunocytochemistry;
  • leukophenotyping;
  • alkaline phosphatase anti-alkaline phosphatase (APAAP);
  • quality control;
  • quality assurance

Monoclonal antibody technology is now used in many haematology departments for the analysis and phenotyping of haematological malignancies. Immunocytochemical analysis, in particular the alkaline phosphatase anti-alkaline phosphatase (APAAP) technique is increasing in popularity. This paper describes the findings from the 1st year of an external quality assurance scheme for immunocytochemistry. Initially, there was a wide variation amongst the results received. An improvement was seen over the year with subsequent concordance in the results. This variation could be due to a number of variables within the technique which this report highlights.