In this lecture Professor Zach Murphy will be presenting on CBC | Approach to Polycythemia. If you would like more information on the RBC Life Cycle and Destruction, please watch our videos listed below in our Hematology playlist. We will then move into our systematic approach on how to interpret a CBC and what tests are relevant to ordering. In this lecture we differentiate between Primary and Secondary Polycythemia, and Relative Erythrocytosis, we will also discuss systematically how to recognize Appropriate vs Inappropriate absolute increase in RBC due to secondary polycythemia. at the end of the lecture, there are some Polycythemia case studies, to better apply the knowledge in the lecture. We hope you enjoy this lecture!