A cluster of differentiation (CD) antibody microarray called the DotScan microarray has been developed that enables an extensive immunophenotype to be obtained for a suspension of leukocytes in a single analysis. For a leukemia with a leukemia count of greater than 10 x 10(9)/L, the immunophenotype obtained is essentially that of the leukemic clone. The antibody microarray is printed as microscopic (10 nL) dots on a nitrocellulose film on a microscope slide. Cells are captured by the immobilized antibodies and a dot pattern is recorded with an optical array reader giving the immunophenotype of the leukemia. Procedures are being developed that should enable diagnosis of myeloid leukemias by comparison of the dot pattern obtained from an unknown blood sample with a library of consensus patterns for the common leukemias.