Oscillation of Lasota-Wazewska model with positive and negative coefficients

In this piece of paper, an example of L-W model of red blood cell survival was considered. The probability of cell death was taken as a function using a first-order nonlinear delay equation with positive and negative coefficients. Some sufficient conditions obtained to ensure the oscillation of RBCs numbers around the equilibrium. Oscillation of Polycythemia and anemia for female and male about equilibrium investigated, two illustrative examples are given.