March 2018

Transfusion of K negative RBC for Females of Child-bearing Potential

D. Neurath, Manager, Transfusion Medicine, EORLA TOH sites
M. Tokessy, Change technologist, Transfusion Medicine, EORLA TOH General campus
H. Maddison Medical Technologist, Transfusion Medicine, EORLA TOH General campus
N. Cober Charge Technologist Transfusion Medicine, EORLA TOH Civic campus
S. Love Charge Technologist, Transfusion Medicine, EORLA TOH General campus
B. Ludington Medical Technologist Transfusion Medicine, EORLA TOH General campus

ABO and Rh(D) matching for red blood cell (RBC) transfusions is the standard of care to ensure safe blood transfusion and to circumvent alloimmunization to the D antigen. The prevention of Rh(D) alloimmunization is especially important for females of child bearing potential, in that maternal anti-D is known to cause hemolytic disease of the fetus and newborn (HDFN). Anti-K has been known to also cause severe HDFN. With no available prophylaxis, there is no protection for anti-K alloimmunization in pregnancies. While the incidence of K antigen is low, only 9%, its antigenic nature makes it a frequent antibody producer. Alloimmunization is mostly attributed to transfusion of K positive red blood cells (RBC). Selection of K negative RBC for blood transfusions to females of child-bearing potential will prevent development of anti-K in this vulnerable patient population.


A review was performed using the regular blood inventory to determine if sufficient number of K negative RBC units would be available for transfusions. It was determined that indeed we would have sufficient available inventory of K negative RBC for transfusions to female patients of child-bearing potential.


Each patient has a transfusion history check done prior to performing Type and Screen. All females identified as < 45 years old meet the criteria for selection of K negative RBC for blood transfusion to prevent alloimmunization. The existing inventory on hand is used without need for special requests from the Canadian Blood Services (CBS) for K negative RBC.


In May 2017 we implemented a process for all female patients of child-bearing potential to be transfused with K negative RBC. Between May 1, 2017 to December 31, 2017 there were 342 female patients in this category requiring blood transfusions of 1906 RBC units. The numbers include sickle cell exchanges; a total of 35 female patients requiring 721 RBC that were specifically requested from CBS for exchanges. Additionally, there were 13 patients requiring multiple transfusions, between 15 to 30 RBC units each. The K negative RBC inventory was most often sufficient and in-house phenotype was performed only when supply was depleted. The exception in this process occurs during a massive transfusion in which the critical situation does not allow it.


Considering the severity of hemolytic disease of the fetus and newborn due to anti-K and the readily available K negative RBC, we feel we are proactive in trying to eradicate anti-K alloimmunization by transfusion in the female population of child-bearing potential. The cost is negligible as the existing inventory of K typed RBC is mostly used.


What is the Canadian Obstetrical and Pediatric Transfusion Medicine Network (COPTN)?

Gwen Clarke MD, Hematopathologist with Canadian Blood Services and Clinical Professor in the Department of Lab Med and Pathology at the University of Alberta
Lani Lieberman MD, Assistant Professor, University of Toronto and Transfusion Medicine Specialist, University Health Network and affiliated hospitals
Denise Evanovitch, ORBCoN Regional Manager, SW Ontario

The Canadian Obstetrical and Pediatric Transfusion Medicine Network (COPTN) is a subcommittee of the Canadian Society for Transfusion Medicine (CSTM) and was established in 2017. The membership consists of volunteer physicians, technologists and health care providers from across Canada with expertise in obstetrical and neonatal testing, transfusion and care. The subcommittee’s mandate is to assess, analyze and strive to implement best practices in pediatric and obstetrical transfusion practice in Canada. ORBCoN was invited to participate as a member of this group.


COPTN members frequently field obstetrical/neonatal questions from hospitals. Many of these issues are not included in transfusion and accreditation standards such as CSA, CSTM, IQMH and Accreditation Canada. Thus, there is a need for guidance on best practices in Canada for this patient group that is readily available for all pertinent specialties.


The COPTN’s objectives are to:

  • Survey practice related to pediatric and obstetrical laboratory testing and transfusion across various hospitals in Canada
  • Assess the literature regarding optimal transfusion practice and to share results with members
  • Discuss and develop national research projects in obstetrical and pediatric transfusion medicine
  • Develop best practice recommendations in pediatric and obstetrical transfusion practice
  • Serve as a forum to discuss challenging pediatric/obstetrical cases
  • Promote the safe use of blood products to pediatric and obstetrical patients

The first large scale initiative of COPTN is a Canada-wide survey of obstetrical and neonatal testing practices. It will be distributed to hospitals and other laboratories that conduct this type of testing (e.g. some Canadian Blood Services laboratories)and will be sent to participants in every province and territory. The purpose of the survey is to assess the current practice with regard to ABO, Rh, antibody screening, fetal-maternal hemorrhage assessment and RhIG administration. This analysis will provide a needs assessment of sorts to assist COPTN in prioritizing which guidance to develop first in order to provide the most benefit.


COPTN members developed the survey using the LimeSurvey® software and will be analyzing the results, which will be shared with the participating hospitals and laboratories. The survey does cover a large range of practice, so it is a longer one, but there is logic incorporated into the questions, so not all questions will require an answer from all respondents. It is divided into sections and you can stop and save your results at any time and continue completing the survey later. It will be distributed in the spring of 2018 and you will have six weeks to complete it. We would like a response from each hospital/laboratory. (rather than a single response from a health region).


We strongly encourage you to take the time to do this survey as the ultimate goal is to provide standardized, best care to obstetrical and neonatal patients throughout Canada. We look forward to your participation. Together, we can improve patient care across Canada.