7.4 Cord blood utilization and alternatives to allogenic blood

Several safety, effectiveness and feasibility studies have been conducted in low income countries on collection and utilization of cord blood for transfusion purposes and an extensive review  on the subject  has been recently published (1) .

7.3 Predeposited autologous blood, intraoperative blood salvage and autotransfusion

The threat of HIV transmission during the 80’s favored the dissemination of autotransfusion practices in surgical patients.
Autologous blood units (i.e. to be re-infused to the same subject) may be collected days or weeks before surgery when a significant perioperative blood loss is foreseen. They can be stored in the blood bank like other blood units and utilized when needed. This is also called predeposited blood.

7.2 Prevention of anemia and of perioperative bleeding in the surgical patient

A. Preoperative preparation

A proper preparation of the patient that will undergo major surgery can be useful  in reducing the risk of severe post-operative anemia. This is particularly important in patients suffering  from nutritional deficiencies or from chronic blood loss.

7.1 Reduction of transfusion needs: public health measures

Given the risks associated with blood transfusions all available preventive measures should be in place in order to reduce the occurrence of clinical situations where transfusion comes as the last life-saving resort.
It is not the scope of this manual to discuss in detail the strategies of anemia prevention at  thecommunity level, however we will briefly mention the ones that are at present the most rational and feasible.

6.4 Indicators of blood transfusion activity and quality

For all the steps in the  blood transfusion process a set of essential indicators should be regularly  calculated and monitored in order to:
• keep the most critical steps under control
• assess the level of achievement of the transfusion service objectives

6.3 Quality management tools and documents in transfusion medicine

Focusing more specifically on quality management -QM- tools relevant in transfusion medicine the following elements must be considered:

6.2 Quality Management System : an overview

During the last decades an increasingly complex set of tools and procedures have been developed and applied in the field of manufacturing processes in order to deliver  products of reliable quality. These instruments, with some adaptations, have been transposed to the health sector with the aim to improve the quality and to reduce the errors in clinical and laboratory practice. 

6.1 Organization models and costs of blood transfusion services

In the variety of African scenario there are different approaches to blood transfusion services according to national policies, actors (private/public), resources and geographical characteristics. In developing countries three schemes of transfusion systems have been described :

5.3 Transfusion reaction management flow chart

5.2 Management and monitoring of the patient during transfusion

Also under the best conditions blood transfusions may cause mild to moderate/severe adverse events - or transfusion reactions - in about 1-3% of cases. The majority of these are usually mild immunological reactions like non hemolytic febrile reactions (due to anti-leukocyes antibodies) or skin allergic reactions. In Africa a higher rate of transfusion reactions has been reported (1) , the reasons of this excess morbidity remain to be clarified. 

5.1 Pre-transfusion procedures and patient preparation

When pre-transfusion tests have been performed and suitable safe blood is available it is possible to proceed to infusion.
Informed consent to any invasive medical procedure is today a basic patient right and so before transfusion it should be obtained directly from the patient or, in case of children, from the parents. Information should be tailored in order to be understandable and culturally acceptable to average community members.

4.3 Prevention of bacterial contamination

There have been several reports on alarming levels of bacterial contamination in stored blood bags from different surveys conducted in sub Saharan Africa. According to these investigations bacteria were cultured in 8 to 17% of stored blood units. (1,2) This contamination level is thousands of times more than what is observed in high income countries.
Significant bacterial contamination of  blood units may be the result of any or of the followings :

4.2 Blood storage

After collection and having pre-transfusion tests done blood can be transfused as “warm” whole blood within 8 hours or it can be stored at 4°C for 28-35 days depending on anticoagulant-preservative solution. If facilities allow (but it is rarely the case in sub-Saharan Africa) soon after collection whole blood can be separated into components (concentrated RBC, plasma and platelets) and each component stored accordingly (1) .

4.1 Blood collection

Donated blood is collected utilizing appropriate single-use plastic bags equipped with close-circuit tubing and needle. They contain the appropriate amount of anticoagulant-preservative solution for a determined amount of blood. Bags for collection of 150, 250, 350 and 450 mls of blood are available.

3.11 Compatibility testing flow chart

3.10 Compatibility for irregular antibodies utilizing the Indirect Antiglobulin Test

There are many antigens on RBCs like Rh-D  that, when are transfused to patients who lack them, can stimulate the production of specific antibodies. The presence of “irregular” -non anti-A/B- , antibodies must be ruled out if lab facilities allow before issuing blood for transfusion.

3.9 Summary of ABO-Rh compatibility and documentation

The basic compatibility tests presented in the previous pages (ABO front typing, room temperature cross-match and Rh-typing) are simple and affordable and must be correctly performed in all basic laboratories that issue blood for transfusion. All is needed are commercial anti-A, anti-B and anti-Rh-D antisera, a refrigerator, normal saline solution, glass (or plastic) pipettes and tubes and, possibly a simple centrifuge .

3.8 Rh-D typing and compatibility

The antigen Rh-D, commonly called Rh , is one of the many antigens that are  present on RBCs surface and that, if transfused to patients who lack it (Rh negative), can stimulate the production of specific anti-Rh antibodies.


3.7 ABO grouping discrepancies resolution

At a basic laboratory level it may be difficult if not impossible to resolve a discrepant front and reverse grouping and/or an incompatible room temperature cross-match of otherwise ABO “compatible” blood.

If the ABO grouping discrepancy cannot be resolved there are two possible options:

3.6 Room temperature cross-match and immediate spin

A simpler way to confirm ABO compatibility between the recipient and the donor blood is to match directly patient serum/plasma with the donor RBCs suspension in a similar manner as described for reverse grouping (see section 3.5). This is called room temperature –RT- cross match. Again it can be done on a tile but, for the reasons already mentioned, the tube test is a more accurate technique. The test  in tube is also called immediate-spin.

3.5 ABO typing : front and reverse

ABO typing has two stages: one direct red blood cells -RBCs- typing using commercial antisera (anti-A, anti-B) and one indirect typing utilizing plasma/serum and known - A and B - RBCs suspensions.

1. Direct ABO blood typing (or front grouping)

This test detects the presence of A and B antigens on RBCs surface by means of agglutination utilizing commercial antisera. It is a basic and simple test, it can be performed on few drops of venous or capillary blood (i.e. obtained by finger pricks) .


3.4 Principles of ABO compatibility

A clear understanding of ABO group system compatibility is fundamental in order to prevent acute immune hemolytic reactions. In this system four combinations of A and B antigens are possible: A, B, O and AB. In Africa group O is the most frequent, it is found in about 50% of subjects, followed by A, 25-30%, then B , 15-20%, while AB group is carried only by 3-4% of individuals. 

3.3 Blood compatibility and agglutination tests

Compatibility tests are relatively simple to perform however given their importance for patients safety they require great attention and accuracy. A transfusion service, however basic, calls for essential and definite laboratory standards to be met in terms of properly working equipment, adequate supplies, quality control tools, training and supervision.

3.2 Specimens and reagents for compatibility testing

By compatibility testing we mean the matching between the transfusion recipient serum or plasma with donor red blood cells -RBCs-.

For RBCs typing of ABO system antigens and Rh-D  commercial antisera anti-A , anti-B, anti A,B, anti RhD- are available. These antisera cause direct visible agglutination if the corresponding antigens are present on the tested RBCs. 

3.1 Basics of immunohematology and blood compatibility

In immunohematology compatible RBCs are the ones that, after been transfused,  have a normal survival in patient circulation without early destruction – hemolysis – caused by antibodies present in recipient plasma.

2.5 Other transfusion transmitted infectious diseases tha are not routinely tested

Transfusion transmitted - TT - Malaria is a major threat in Africa. Screening of donors with current  malaria tests (thick film or rapid diagnostic test - RDTs) probably helps to reduce the transmission of malaria. However especially in the case of semi immune individuals (i.e. adults living in endemic areas) the concentration of blood parasites  is often below the test detection treshold but they are still able to infect (1) .

2.4 Screening strategies and donor counseling

Blood can be tested for transfusion transmitted infections -TTIs- either before or after donation. The choice among these two strategies depends on epidemiological and practical considerations. If the risk of discarding the unit is high, if the donors are few and rapid tests are available then it is probably better to test donors before donation.

2.3 Comparative evaluation of screening laboratory methods for HIV, HBV, HCV

2.2 Laboratory screening for Transfusion Transmissible Infections: available methods

Laboratory screening for HIV 1/2 , HCV (hepatitis C) and HBV (hepatitis B) on donated blood must always be made and it represents the minimum safety standard accepted by the WHO . Unfortunately this was shown not to be yet an universal practice at least for HCV and HBV in some rural settings (1) .

2.1 Selection and recruitment of blood donors

A suitable blood donor is a healthy individual of at least 16-18 years of age with a body weight of at least 50 kg for blood donations of 400 to 500 ml of blood. In case  lower amounts of blood are needed , i.e. 300-350 ml, adults weighing less than 50 kg can still donate but without exceeding the estimated 12% of total blood volume.

1.7 Summary guidelines for appropriate blood transfusion

Source: Clinical practice guideline: red blood cell transfusion in adult trauma and critical care. Crit. Care Med. 2009 37(12):3124-57

Indications for blood transfusion:

  • Patients with evidence of hemorrhagic shock require RBC transfusion (level of evidence I).
  • Patients with evidence of acute hemorrhage and hemodynamic instability or inadequate oxygen delivery may require RBC transfusion (level of evidence II).

1.6 Indications: the surgical patient

As far as possible in surgical settings transfusion needs must be predicted, especially in case of elective surgery, in order to have the blood ready when needed. An algorithm useful in deciding when to give scarce blood of uncertain safety in the pre- and postoperative periods has been proposed (1,2) as follows:

1.5 Indications for blood transfusion: therapeutic doses

As already pointed out in high income countries the blood is transfused as concentrated RBCs. This component is prepared utilizing special centrifuges that separate RBCs from most of the plasma, platelets and WBCs. Concentrated RBCs are then suspended in additive solutions that extend storage time up to 42 days and that lead to a final RBCs concentration (Hematocrit or PCV) of about 60-70%. Concentrated RBCs  are available also in some African contexts where central blood banks are adequately equipped for their preparation. However in the great majority of cases in SSA blood is transfused unprocessed as whole blood with a final RBCs concentration of 35-40%. In other words 1 ml of concentrated RBCs corresponds to 1.5 – 2 ml of whole blood. The therapeutic doses presented below refer to WHOLE BLOOD. In case concentrated RBCs resuspended in additive solutions are available proper adjustment of the dose must be made dividing the volume by 1.5.


1.4 Indications: anemia in normovolemic conditions

Etiology and Epidemiology

“Anemia” , i.e. low circulating hemoglobin level, is the most common indication for blood transfusion and even more so in malaria endemic countries. As well known malaria, mostly caused by the deadliest P. falciparum species, is ubiquitous in most of sub-Saharan Africa, with exception of mountainous areas (above 1500 mts), and of majority of South Africa.  In areas with “stable” malaria transmission throughout the year children are the most affected especially during the first years of life and in these cases severe anemia is a common presenting picture. Malaria is also a common cause of severe anemia in pregnant women, in particular in primigravidae (first pregnancy). Pregnant women , and adults in general, may have a very low concentration of malaria parasites and so correct diagnosis may be missed if only based on blood microscopy. Apart from anemia chronic malaria may present with splenomegaly that, in some cases, is associated with weight loss and low platelet counts contributing so to the clinical picture of tropical splenomegaly syndrome.

1.3 Utilization of fresh or warm whole blood

Blood component therapy with the utilization of concentrated red blood cells -RBCs-, fresh frozen plasma - FFP- and platelets -PLT- is generally unavailable in Africa. On the contrary blood is commonly transfused as whole blood. Warm whole blood infused shortly after collection (i.e. after few hours and without refrigeration) preserves all the clotting properties of coagulation factors as well as of platelets.

1.2 Indications for blood transfusion: acute hemorrage

Acute bleeding inside or outside the body causes tissues hypo-oxigenation by two mechanism:

• Decreased blood volume
• Decreased circulating oxygen carrying hemoglobin

A further and late negative event may occur after prolonged massive bleeding, especially in traumas,  that is coagulopathy (i.e failure of clotting) caused by blood dilution and  clotting factors consumption. This situation will be treated separately in the section “utilization of fresh or warm whole blood”.

1.1 Indications for blood transfusion: general considerations

If everybody agrees that “the best transfusion is the one avoided” there are few evidences that support clear-cut indications for transfusion. The scarcity of evidence-based criteria is due to the lack of randomized controlled trials in which transfusion is completely withdrawn from patients belonging to one study arm, option that would be considered unacceptable by any ethical standard. Everybody knows that severe anemia leads to death, few if any know when, on average, it occurs. Individual variation (age imprimis) and co-morbidities make this threshold quite variable. The available documented evidences are mainly coming either from those who refuse blood transfusion or from observations made where no blood is immediately available.

Blood transfusion practice: the African scenario

In many countries of Sub Saharan Africa -SSA-  the indicators of quality and accessibility of health services are slowly but progressively improving. However there is still a huge shortage of accessible and quality diagnostic and curative services especially in remote and impoverished areas where majority of people live.

As far as blood transfusions are concerned the scenario is characterized by the following features: