Providence Cancer Center, Providence Portland Medical Center 1 article published in JoVE Immunology and Infection A Semi-automated Approach to Preparing Antibody Cocktails for Immunophenotypic Analysis of Human Peripheral Blood Yoshinobu Koguchi1, Iliana L. Gonzalez1, Tanisha L. Meeuwsen1, William L. Miller1, Daniel P. Haley1,2, Alice N. Tanibata-Branham3, Keith S. Bahjat1,4 1Human Immune Monitoring Laboratory, Earle A. Chiles Research Institute, Providence Cancer Center, Providence Portland Medical Center, 2Sony Biotechnology, 3Beckman Coulter, Inc. Life Sciences, 4Bristol-Myers Squibb Whole blood Immunophenotyping is indispensable for monitoring the human immune system. However, the number of reagents required and the instability of specific fluorochromes in premixed cocktails necessitates daily reagent preparation. Here we show that semi-automated preparation of staining antibody cocktail helps establish reliable immunophenotyping by minimizing variability in reagent dispensing.