Final answer:
The Sysmex is an instrument used to count RBCs and determine Hct using impedance counting method.
Step-by-step explanation:
The Sysmex is an instrument commonly used in medical laboratories to count red blood cells (RBCs) and determine hematocrit (Hct). The Sysmex uses a method called impedance counting, which involves passing a blood sample through a small opening and measuring the electrical impedance caused by the cells.
The change in impedance is recorded and used to calculate the number of RBCs present. The hematocrit is determined by measuring the percentage of the sample's volume that is occupied by RBCs.