In this study, the investigators will be evaluating the impact of red blood cell age in patients receiving chronic blood transfusions in the outpatient setting. This study will have a double-bind, randomized trial design, meaning that the investigators and participants will not be told the group assignment at study enrollment.

Study participants will be randomly divided into two groups (50% of participants in each group) by a computer generated block randomization schema. The 'fresh blood' group will receive blood units that are 7 or less from the time of donor collection, and the 'aged blood' group will receive blood units that are greater than 21 to 42 days from the time of donor collection. The number of units of blood transfused will be decided based on the participant's hemoglobin level before blood transfusion.

The primary goal of our study is to compare annual red blood cell product use (the number of units given per patient in a year). The investigators will also be comparing groups to evaluate the transfusion reaction frequency, iron burden (based on the level of ferritin in the blood), overall transfusion and care cost difference, and participant time spent in outpatient departments.

Our hypothesis is that use of fresh blood in chronically transfused patients will lead to a decrease the in red cell transfusion rate, with subsequent clinical benefits including reduction of transfusion reaction frequency and systemic iron burden.

This study will be taking place within the Calgary Zone of Alberta Health Services only.

Background: Chronically transfused medical outpatients comprise a significant proportion of transfusion recipients annually. At this time, the impact of red cell transfusion on patient outcomes in this patient population is unknown.

Objective: Our goal is to prospectively evaluate impact of red cell age on product utilization in a cohort of chronically transfused medical outpatients randomized to receive red blood cells that are fresh (≤ 7 days from collection) or aged (>21-42 days from collection). To our knowledge, no other studies with a similar design or objective have been published.

Patient population and study design: Patients meeting eligibility criteria will be invited to participate in our study. Our chronically transfused outpatient population is defined as adults who are receiving 2 or more red cell units per month for at least 3 consecutive months in an ambulatory clinic setting within the Calgary Zone.

We plan to incorporate both prospective and retrospective data collection and analysis in our study design. All eligible, consenting participants will be randomized into one of the two study arms. Investigators and participants will be blinded to participant group assignment.

Laboratory parameters and red cell transfusion: Parameters of usual pre-transfusion bloodwork will be followed, including complete blood count (CBC) and ferritin levels. Red cell transfusion volumes for chronic transfusion throughout the study will be determined according to a locally established protocol to achieve a post-transfusion hemoglobin (Hb) of 95-105 g/dL. Given that 1 adult unit of red cells raises the baseline Hb by approximately 10 g/L, the following volumes will be given to patients during a single visit based on their pre-transfusion CBC: Hb <75 = 3 units, Hb 75-84 = 2 units, Hb 85-94 = 1 unit, Hb ≥95 = no transfusion. A routine post-transfusion CBC will not be performed. According to usual care, participants will have a standing order to perform a CBC at least weekly, or if they have subjective symptoms of anemia to help guide subsequent transfusions.

Study participants will receive blood transfusion in usual locations designated within the Calgary Zone for administration of chronic blood transfusions. These include medical daycare units at the Foothills Medical Center, Tom Baker Cancer Center, Peter Lougheed Center, and South Health Campus. Nurses will administer blood transfusions according to standard practice, without change in transfusion protocol despite patient study participation.

Duration of participation will be 1 year from the time of enrollment. Participant health record access will be required for collection of demographic information and retrospective data involving any transfusions received within 1 year prior to enrollment to establish transfusion chronicity and health patterns. Outcomes will be based on a comparison of results between the study groups. Prospectively collected data based on red cell age will additionally be compared to retrospective transfusion related information (including red cell transfusion frequency and blood age) from within 1 year from the time of enrollment, if available. We plan to enroll a maximum total of 60 participants, with assignment of 30 patients into each group.

Inclusion Criteria:

• Patients requiring outpatient chronic red cell transfusions (2 or more red blood cell units per month for at least 3 consecutive months) in an ambulatory clinic within the Calgary Zone

Exclusion Criteria:

• prerequisite for fresh or irradiated blood due to a pre-existing medical reason
• hemodialysis dependence
• chronic disease that has acutely decompensated, with a life expectancy of less than 3 months