(P-IV-6) Too Much Of a Good Thing: Giving Old Rhd- Red Blood Cells To Rhd+ Recipients.

The ample supply of O RhD- red blood cells (RBCs) in Denmark means that O RhD- remains the national standard for emergency transfusions, i.e. patients without a valid ABO-type.

As such, the general aim of the Blood Service of the Region of Southern Denmark (RSD) is to provide O RhD- for emergency transfusions, and at minimum always being capable of providing O RhD- RBCs to RhD- and RhD type-unknown females of childbearing age (FoCA). This necessitates a large inventory of O RhD- RBCs. To minimize waste, O RhD- and other RhD- components are occasionally issued to patients with other blood types in non-emergency transfusions. This practice can result in issuing products closer to expiry and might be viewed as a waste or misuse of O RhD- products.

Supplying O RhD+ for emergency RBC transfusions to non-FoCAs could be a reasonable alternative.

The aim of this study was to examine the utilization of RhD- RBCs in RSD.

Study

Design/Methods:

All blood banks in RSD operate under the supervision of a single central department.

Inventory data and data from all RBC transfusions in RSD from Jan 1 2020 to Dec 31 2023, were extracted from the RSD’s blood banks’ inventory and laboratory IT system ProSang®. Inventory data was converted to relative deviations from corresponding annual inventory average.

Data was analyzed using Microsoft Excel® 2016. A p-value of ≤ 0.05 was considered significant.

The study was approved by the hospital administration as a quality improvement project.

Results/Findings:

The study included 134,988 RBC transfusions to 25,845 patients. Transfusions to RhD- FoCAs accounted for 1,235/134,988 (0.9%) of all RBC transfusions.

In non-emergency O RhD- transfusions, 5,437/13,217 (39.3%) were issued to recipients who were not O RhD-. O RhD- RBCs had a significantly higher discard rate (5.6%) than the average of all other types (2.4%) (p-value < 0.05).

Table 1 presents the average number of days to expiry by RhD-matching and component type in non-emergency transfusions. O RhD- RBCs issued to other blood types were significantly closer to expiry compared to other products.

Using linear regression, we analyzed weekly switch-rates of O RhD- to O RhD+ as a function of the corresponding weekly O RhD- and O RhD+ inventory. Switch-rates had a significant positive correlation with increases in both RhD- and RhD+ inventory; correlation coefficients 0.32 (CI95% [0.39; 0.25]) and 0.18 (CI95% [0.22; 0.14]) respectively.

We were always capable of providing RhD- components to FoCAs.

Conclusions:

O RhD- RBCs had the highest discard rates and were frequently issued to patients with other blood types in non-emergency transfusions. These products were older than RhD-matched products. These issues are caused by keeping a large O RhD- inventory so re-evaluation of emergency RBC transfusions is needed.