Apparent superiority of two‐step 70% isopropyl alcohol over chlorhexidine alcohol for skin antisepsis prior to blood donation

Abstract

Abstract Background The use of chlorhexidine containing agents for skin disinfection prior to blood donation has long been recommended by WHO, with alcohol‐iodine solutions or deferral suggested as second line agents for chlorhexidine allergic donors. These recommendations, however, have a limited evidence base being derived principally from expert opinion and extrapolation from studies investigating skin disinfection for other invasive procedures. Australian Red Cross Lifeblood (Lifeblood) policy is for a one‐step alcohol‐chlorhexidine method as the first line process, and a two‐step 70% isopropyl alcohol method for chlorhexidine allergic donors. Study Design and Methods A retrospective quality improvement analysis of Lifeblood data from 2020 to 2025 comparing rates of bacterial contamination screening (BCS) positivity and transfusion transmitted bacterial infection (TTBI) between donors receiving one‐step alcohol‐chlorhexidine and two‐step 70% isopropyl alcohol for chlorhexidine allergic donors. Results 6,732,654 total donations occurred with 66,917 donations from chlorhexidine allergic donors over this period. No TTBIs, nor BCS positive results were identified in the chlorhexidine allergic group, despite expecting 13 (95% CI 12.5–13.5), whilst 2475 (95% CI 2474.6–2475.4) BCS results occurred in the non‐allergic group (χ 2 (1) = 12.93, p = .0003). Discussion This data unexpectedly suggests that the two‐step 70% isopropyl alcohol disinfection method may be superior to alcohol‐chlorhexidine, although a robust randomized trial would be required to satisfactorily answer this question.