Hemodilution - an overview of current canadian practices

Background. Transplant teams evaluate potential organ and tissue donors to exclude donation of tissues at risk for disease transmission. Standards dictate that serological tests be performed on every donor to assess the presence of transmissible diseases including: Human Immunodeficiency Virus 1 & 2, Human T Lymphotropic Virus 1 & 2, Hepatitis C, Hepatitis B surface Antigen, Hepatitis B core Antibody and Syphilis. A limitation of serological testing is the risk of false negative results due to the dilution of the serum. Hemodilution results from the transfusion of fluids (blood products, colloids and/or crystalloid). Confidence in the accuracy and sensitivity of donor serology testing is of utmost importance to ensure the provision of safe organs and tissues for transplantation.Methods. In order to determine the preferred and validated methodology for determining hemodilution, if any; and to determine the level of hemodilution that jeopardizes serologic test results, we reviewed the literature and current testing practices. Tissue banks throughout Canada as well as accrediting bodies were contacted regarding the hemodilution algorithm they utilize.Results. In the absence of a pretransfusion sample, hemodilution calculations are the prevalent methodology for assessing sensitivity of serology testing. A literature search and personal communications provided no documentation on the validation of any hemodilution algorithm or evidence that 50% hemodilution is an acceptable level for accurate serology testing.Conclusion. A validation of hemodilution algorithms and the acceptable or unacceptable rate of hemodilution is required. The utilization of a validated algorithm should be mandated in standards to ensure continuity of practice by all transplantation centres. If validation cannot be obtained, alternative methodologies for serology testing should be investigated.