Red blood cell mass in autologous and homologous blood units. Implications for risk/benefit assessment of autologous blood crossover and directed blood transfusion.

Abstract

A prospective analysis of 300 consecutively collected homologous blood (HB) units from a regional blood center and an analysis of 188 consecutively collected autologous blood (AB) units from a community hospital was conducted. Analysis of the red blood cell (RBC) mass content of these blood units revealed that HB contained 13 percent more RBC than AB: 200 +/- 1.1 vs 177.1 +/- 1.1 mL, (m +/- SE), respectively (p less than 0.05). Of 174 AB units eligible for crossover by AABB criteria for RBC mass (greater than or equal to 154 mL), 35 (20%) were below the 95 percent confidence interval range for RBC mass of HB units collected; mean RBC mass of 300 HB units was 12 percent greater than that of 174 AB units (200.1 +/- 1.1 vs 178.9 +/- 0.9 mL, p less than 0.001) and 20 percent greater than that of the 35 AB units outside the 95 percent confidence interval (200.1 +/- 1.1 vs 161.2 +/- 0.5 mL, p less than 0.001). These findings indicate that an evaluation of the issues of AB crossover for HB transfusion should include a risk/benefit analysis of AB units with lower RBC mass. These findings also indicate that the proposed changes in AABB standards regarding directed donation (DD) should consider the reduced benefits of DD units with lower RBC mass in a risk/benefit analysis of this practice, and support retention of homologous donor standards for directed donors.