Asian Journal of Transfusion Science
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A clinical audit on the utilization of group O-negative red cells and the lesson learnt

1 Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
2 Department of Pathology, Dow University of Health Sciences, Karachi, Pakistan
3 Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan

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Date of Submission20-Nov-2021
Date of Decision01-Mar-2022
Date of Acceptance15-May-2022
Date of Web Publication26-Sep-2022


BACKGROUND: Ideal blood inventory management involves guaranteeing maximal availability of blood while minimizing wastage. Benchmark for the guidance of O (Rh) D-negative red blood cells (ONEG RBCs) is not widely available. In this study, we aimed to identify the areas of improvement in blood center inventory of ONEG RBCs through a clinical audit.
MATERIALS AND METHODS: During April 2017 to March 2018, patients who received ONEG RBCs units were studied for their demographics, primary reason for admission, location, and clinical condition. Data were collected from computerized blood center information system, online integrated laboratory data (Integrated Laboratory Management System), and patients' medical record charts. Children at ≤18 years were included in the pediatric population as per our institutional criterion while a female between 15 and 49 years was considered as having childbearing potential according to previously published data.
RESULTS: Overall, 807 units (2.8%) of ONEG RBCs were transfused during 577 transfusion events with a median (inter quartile range) of 2 (1–3) units per patient in each transfusion event. Recipients of ONEG RBCs were 221 unique patients including 91 females (41%) and 130 males (59%) and only 44 (20%) females had child-bearing potential. Overall, 72 of 807 red cell units (8.9%) were transfused to young females of O/non-O negative/unknown group and were classified as “obligatory.” Neonates, pediatric patients, chronically transfused, and bone marrow transplant recipients received 337 of 807 (42%) units and were marked as “acceptable.” Transfusion of 398/807 units (49%) to females of nonchildbearing potential and adult males could have been saved for those with a mandatory transfusion requirement of ONEG RBCs.
CONCLUSIONS: This clinical audit showed that 409 of 807 of ONEG RBCs (51%) were transfused according to the guidelines while 398 of 807 of these (49%) could have been saved for other mandatory requirements. Appropriate policies, planning, education of physicians, and regular clinical audits are needed to bring the desired change in transfusion practices.

Keywords: Blood storage, donors, red cells

How to cite this URL:
Ali AA, Qadir H, Khalid A, Moiz B. A clinical audit on the utilization of group O-negative red cells and the lesson learnt. Asian J Transfus Sci [Epub ahead of print] [cited 2023 Mar 24]. Available from:

   Introduction Top

COVID-19 has adversely affected human life and blood donation is no exception. Blood centers are facing new challenges for maintaining an optimum inventory. Blood donation was slow in the initial days of pandemic possibly due to apprehension of blood donors for contacting infection in blood centers,[1] limited mobility in lock downs, migration of industry workers to villages, and closure of education centers. More recently, postvaccination donor deferral for 2–4 weeks has compromised the collection of blood units in many regions.[2] As there was a significant decline in blood donation across blood groups, a proportionate drop in reserves of rhesus negative-blood units was also observed during the COVID-19 pandemic.[3] Choosing wisely campaign was started in pre-COVID era and drew attention toward restricted usage of blood transfusion in patients with stable anemia.[4] This positively reduced the need of blood transfusion in the USA by 2.5% in 2019 when compared to the same in 2017.[5] Despite more restrictive transfusion thresholds and a decrease in trend of blood transfusions, the demand for O(Rh)-D negative red blood cells (ONEG RBCs) has not reduced significantly.[6] Dunbar and Yazer. in 2018 studied 31 centers in United States and observed that ONEG RBCs constituted 3.0%–13.9% of all the red cells units that were transfused.[7] This demand is apparently mismatch with the frequency of ONEG blood group in white non-Hispanic-, Hispanic-, black non-Hispanic-, and Asian-blood donors (8.0%, 3.9%, 3.6%, and 0.7%, respectively) in the data base of 3.1 million US blood donors.[8] This discrepancy in supply and need requires optimization of ONEG RBCs stocks. Moreover, excess utilization of ONEG RBCs causes immense pressure on blood donors with ONEG blood group for donating more frequently.

ONEG RBCs are extremely essential and lifesaving in emergencies that require immediate blood transfusion in a patient with an unknown blood type.[9] Therefore, it is imperative for the blood center to maintain an adequate stock of ONEG RBCs even in pandemics and catastrophes. American Association of Blood Centers (AABB) released a bulletin in pre-COVID times to cater the growing concern of over-reliance on ONEG RBCs. Similar guidance was released by National Health Service (NHS) blood and transplant to ensure consistent clinical and laboratory management of O red cells.[10] In Pakistan, almost a quarter of women may require blood transfusion during pregnancy due to anemia.[11] Therefore, ONEG RBCs should be reserved for females of childbearing age who are group ONEG, those who are non-ONEG but require transfusion while type-specific blood is unavailable, and those of unknown blood type who require RBCs before the completion of pretransfusion testing.[12] Ideally, blood group should be known at the time of delivery as its mandatory to perform blood grouping during antenatal workup. However, in our country, proportion of un booked cases may be as high as 70%.[13] requiring reserving ONEG RBCs for such emergency conditions. Monitoring utilization of ONEG RBCs inventory is also essential with a prompt switch to Rh (D)-positive RBCs when possible.[12]

Situated in South Asia, Pakistan is a home to 220 million people with diverse ethnic background. As per an estimate, 3 million red cell-units are required annually in the country,[14] but the proportion required of ONEG RBCs is not known. The frequency of ONEG blood group is extremely variable in the general population ranging from a low of 3%.[15] to a high of 10% in its various regions.[16],[17] Aga Khan University Hospital (AKUH) is a 700-bedded academic medical center and is located at Southern Pakistan. AKUH-blood center collects, processes, stores, and supplies blood and blood products to its admitted patients. Our previous 5-year blood center data showed that only 2997 of 117,560 blood donors (2.5%) had ONEG blood group. AKU blood center collected 28179 blood units in 2019 which dropped significantly to 22268 in 2020 (a 20% decrease). Blood center dispensed 230 ONEG RBCs against the request of 530 units during January–November 2020 equivalent to completion of 43% requests. Hence, in 2021, hospital transfusion committee reviewed the utilization of ONEG RBCs for optimizing inventory management. This study was done to identify the situations where ONEG RBCs can be conserved and to identify the gaps that need intervention for improvement.

   Materials and Methods Top


A clinical audit was conducted at The Section of Hematology and Transfusion Medicine, Department of Pathology and Laboratory Medicine, at the AKUH over a period of 12 months from April 2017 to March 2018. At AKUH, clinicians order blood products through computerized physician order entry (CPOE) which is an in-house blood center information system with programmed indications for blood products. The system is capable of two-way communication between physician and blood centre and can retrieve data for quality checks and audits.

Data collection

Data were collected from computerized blood center information system, online integrated laboratory data (Integrated Laboratory Management System), and patients' medical record charts. All patients who received ONEG RBCs during the study period were included and their demographics, primary reason for admission, location, and indication of using ONEG RBCs were studied. Patients who were transfused with other blood products such as plasma and platelets or with non-ONEG RBCs were not included in the study. As per our institutional criterion, children of 18 years or less were included in the pediatric age group while women between 15 and 49 years were considered to have child bearing potential as per previously defined criteria.[18]

Statistical analysis

Statistical Package for the Social Ssciences software version 22 was used for data entry and analysis (IBM, SPSS Statistics V22; Chicago, IL, USA). Results were calculated as frequency for qualitative variables and mean ± standard deviation (or median and inter quartile range [IQR] for skewed data) for quantitative variables. The utilization of red cells was categorized into various clinical services and indications for transfusion and compliance was checked against the standards[10],[12] set by AABB (bulletin #19-02) and NHS [Table 1]. The criteria for compliance were set at 100%. For each indication, % of avoidable transfused units was calculated as per recommendation (a) and % compliance was considered as 100-(a). The audit results were classified as “justifiable” and “avoidable” transfusion of ONEG RBCs.
Table 1: Acceptable/recommended indications for appropriate use of O negative red cells used as standards in this study

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Ethical concerns

The study was Approved by Ethical Review Committee of Aga Khan University (ERC-4841-Pat-ERC-17).

   Results Top


During the study period, a total of 22,720 red cell units were transfused. ONEG RBCs constituted 2.8% (n = 807) of the units that were transfused. In all, there were 577 transfusion events and a median (IQR) of 2 (1–3) ONEG RBCs was administered per patient per transfusion event. Recipients of ONEG RBCs were 221 unique patients including 91 females (41%) and 130 males (59%) and only 44 (20%) females had child-bearing potential. The median (IQR) age of recipients was 34 (17–56) years and the frequency of males surpassed females in each age group except in the 4th and 6th decades [Figure 1]. There were 12 neonates (5.4%), 45 children (20.4%), 91 adults (<50 years) (41.2%), and 73 adults (33.0%) who were between 51 and 89 years. Overall, 827 units of red cells expired (3.2%) from a total of 25,989 units that were collected.
Figure 1: Demographics of 221 recipients of O negative red cells

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Characteristics of patients

Clinical services such as surgery (n = 56), medicine (n = 40), hematology/oncology (n = 32), and pediatrics (n = 28) utilized 70% of the ONEG RBCs [Figure 2]. Primary reasons for hospital admission of these patients were cancer (n = 231, 29%), trauma (n = 136, 17%), thalassemia (n = 104, 13%), and cardiac diseases (n = 106, 13%) [Table 2]. Blood groups of recipients were ONEG (n = 143), non-ONEG (51), Rh positive (n = 10) while unknown in 17 patients [Figure 3]. Therefore, 65% of recipients were ONEG. The reasons for using ONEG RBCs in patients of other groups were the nonavailability of specific groups or the risk of expiry and wastage of ONEG RBCs.
Figure 2: Various clinical areas where O negative red cells were transfused in 221 patients

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Figure 3: Distribution of blood group in 221 recipients of O negative red blood cells

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Table 2: Clinical details of 807 units of O negative red cells in 221 patients with their primary diagnoses

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Audit of utilization of ONEG RBCs

[Table 3] summarizes the utilization of ONEG RBCs in various situations. Overall, 72 of 807 red cell units (9%) were transfused to young females of O/non-ONEG/unknown group and were classified as “obligatory.” A substantial proportion of inventory, i.e., 337 of 807 (42%) units were administered to neonates, pediatric patients, chronically transfused and bone marrow transplant recipients and were marked as “acceptable” based on their blood groups and underlying disorders. Transfusion of 398/807 units (49%) to females of nonreproductive age group and adult males was considered “avoidable.”
Table 3: Clinical audit for utilization of O negative red cells

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Gap analysis

Gaps identified were the absence of blood center policy defining the release of O positive RBC (OPOS RBCs) to patients with ONEG blood group during the shortage of ONEG RBCs and the guidance for replacing ONEG RBCs by OPOS RBCs in the massive transfusion protocol. Moreover, the minimum stock for ONEG RBCs was not defined that need to be maintained on daily basis. Red cell antibody screening was not performed at the time of compatibility testing that could have eliminated the use of ONEG RBCs in elderly females and adult males having ONEG blood group in the absence of anti-D alloimmunization.

   Discussion Top

This clinical audit indicated that 51% of O negative RBCs were utilized according to the standards, but also suggested that an almost equal proportion (49%) could have been conserved. It was also noticeable that 27% of the recipients were non-O negative. These observations are parallel with an international survey of transfusion practices in 30 centers from 11 countries showing that 43% of O negative- RBCs were used for the patients who were non-O negative.[19] Another study called OPTIMUS surveyed transfusion practices and management of O negative- RBCs at 31 US centers and concluded that 44.5% of ONEG RBCs would have been conserved by transfusing OPOS RBCs to ONEG patients who were 50 years or older thus avoiding the shortages of ONEG RBCs.[7]

Transfusing Rh positive RBCs to Rh negative recipients carries the risk of alloimmunization and in case of women, there is also a risk of hemolytic disease of fetus and newborn in future pregnancies. Anti-D formation after transfusion of Rh positive blood to a Rh negative recipient is approximately 20% for RBCs and is <4% for platelets.[20] Widely variable rate of Rh (D) alloimmunization ranging from 21% to 26% in hospitalized patients has been reported.[7] In this study, 115 of 136 units (84%) were transfused to 11/21 trauma patients (20 male/1 female) who were later identified to be ONEG blood group. The blood center might consider issuance of OPOS RBCs in such circumstances.

A retrospective 10-year analysis on 129 trauma patients with Rh negative blood group receiving Rh-positive red cells demonstrated the development of anti-D in 7.8% patients after a median of 161.5 days.[21] In contrast, a very high frequency of 42.7% Rh (D) alloimmunization was observed in 96 male trauma patients following transfusion of three units (range 1–35) of Rh (D)-positive red cells.[22] Although patient population in both cases were young males having trauma, difference in study designs might be contributory to such variance in the results. Selleng et al. in 2017 conserved 10% of ONEG RBCs by transfusing 2836 OPOS RBCs to 437 emergency patients and identified a risk of 3%–6% of developing anti D antibodies.[23] These studies indicated that although the risk of anti D-alloimmunization for Rh negative patients is variable, but it is significant and cannot be ignored. Therefore, OPOS RBCs may be transfused to young patients having ONEG blood group only in life threatening situations and that too during shortage of ONEG RBCs.

Among females of child-bearing age, it is important to prevent anti-D formation to prevent hemolytic disease of the fetus in future pregnancies. Our previous study demonstrated an overall risk of 2.9% for maternal alloimmunization with anti D (due to previous transfusions and pregnancies) with an absolute low risk of 2.2% because of previous pregnancies.[24] However, in other populations (men and postmenopausal women), this risk does not exist and multiple studies have shown that transfusion of Rh-positive red cells to Rh-negative recipients has not resulted in hemolytic reactions.[20],[25] Therefore, we inferred from our clinical audit that 39% and 10% of ONEG RBCs used in males and in postmenopausal women could have been saved.

Beta thalassemia is a major public health problem in Pakistan. Almost 20% of ONEG RBCs inventory was used in treating patients having thalassemia, aplastic anemia, and myelodysplastic syndrome with ONEG blood group. In patients undergoing chronic blood transfusions such as those having thalassemia, the development of red cell autoantibodies (alloimmunization) is a common problem and formation of such antibodies can lead to hemolytic transfusion reactions. Rate of alloimmunization was 25% in a study in 190 patients with thalassemia and suggested transfusion of phenotypically matched red cells in these patients to avoid the development of red cell allo antibodies.[26]

Benchmark for guidance of ONEG RBCs is not widely available. Ideal blood inventory management involves guaranteeing maximal availability of blood while minimizing wastage.[27] Virk et al. in 2020 devised a novel concept of reducing the average pretransfusion shelf-life of ONEG RBCs (from 11 to 9 days) thereby decreasing the inappropriate usage and saving 185 units during 6 months.[6] Our study showed that ONEG RBCs constituted 3% of all the units released by blood center. A 40% refusal of doctors' requests for ONEG RBCs was almost balanced by 50% avoidable usage of ONEG RBCs stock mandating a minimum of 3% daily stocking of ONEG RBCs in our blood center inventory.

What are the lessons learnt? Following this study, we aim to provide guidance in our in-house CPOE with programed indications for ONEG RBCs. Red cell antibody screening will be done for each patient requiring red cell transfusions and OPOS RBCs will be dispensed for males >50 years or postmenopausal women provided there is no anti-D alloimmunization and they are not on chronic transfusions. Continuous monitoring and audit of ONEG RBCs are planned along with the education of physicians to comply with the policies.

Strengths and limitations

The study assisted in evaluating the utilization of ONEG RBCs in an academic center and helped in identifying the gaps in the inventory management of the blood center. The study was limited being done in a single center and being an academic institute may not reflect the transfusion practices of other blood centers in the country.

   Conclusions Top

We observed the utilization of ONEG RBCs with respect to age, gender, and clinical conditions in an academic care center. The audit showed that 51% of ONEG RBCs were utilized as per standards but a significant proportion of these red cells (49%) could have been conserved by appropriate strategic planning for patients having an absolute requirement of such cell.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

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[PUBMED]  [Full text]  
Bedi RK, Mittal K, Sood T, Kaur P, Kaur G. Segregation of blood inventory: A key driver for optimum blood stock management in a resource-poor setting. Int J Appl Basic Med Res 2016;6:119-22.  Back to cited text no. 27

Correspondence Address:
Bushra Moiz,
Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, Karachi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ajts.ajts_170_21


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2], [Table 3]


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