<qa>  What is the purpose of red blood cell transfusion?Background: Red blood cell RBC transfusion is frequently employed in both ambulatory and hospital environments with the aim of improving patient functional status. The efficacy of this 10.5 billion dollar per year practice however has been increasingly called into question. The Investigators propose to directly measure the impact of outpatient RBC transfusions on at-home functional status by recording several physiological parameters and quantifiable physical activity metrics, e.g. daily energy expenditure and daily total step count, using the ActiGraph wGT3X-BT. This device is an accelerometer-based wearable similar in size to a small watch and is worn at the waist. Study participants will wear the device during the course of their daily activities giving the investigators quantifiable insight into activity levels in the home environment. 