**9.2 Tests carried out in case of suspected delayed haemolytic transfusion reaction**

Laboratory tests show anaemia, increased LDH and bilirubin, decreased haptoglobin and higher white blood cell counts in post-transfusion haemolytic reactions. Bilirubin concentration depends on the severity of haemolysis and liver function.

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red blood cells.

*Post-Transfusion Haemolytic Reactions DOI: http://dx.doi.org/10.5772/intechopen.91019*

the transfused blood cells occurs.

several months [9].

Serological tests show positive DAT and the presence of all red blood cell antibodies that were not detected prior to transfusion. This means that after transfusion of red blood cells, the production of alloantibodies directed to the antigen found on

Positive DAT with anti-IgG reagents or with anti-IgG and anti-C3 reagents is generally seen as two red blood cell populations. It has been observed that in some patients, the coating of blood cells includes not only transfused, but also autologous red blood cells. Positive DAT with anti-IgG and anti-C3d reagents may persist for

Alloantibody testing should be performed in the intermediate antiglobulin test (IAT) and enzyme test. In both methods, in addition to the reference blood cells, the patient's autologous blood cells should be included. Depending on the specificity, alloantibodies responsible for the delayed transfusion reaction activate in characteristic tests, for example, antibodies from the Rh system react in an enzymatic test, often also in anti-globulin testing. In contrast, anti-K, anti-Fya antibodies react in an anti-globulin test. Positive reactions with allogeneic blood cells are accompanied by positive auto control of the patient's red blood cells. Ness et al. [9] showed that the formation of warm autoantibodies after the onset of DHTR is relatively common. Approximately one-third of patients who were examined 25 days after the onset of the reaction presented a positive DAT due to autoantibodies with broad specificity [9]. The incidence of autoantibodies after DHTR may be even higher

Usually, plasma alloantibodies are detectable at 4–7 days after the transfusion and reach maximum activity between 10 and 15 days after the transfusion. When examining recipient red blood cells using a diagnostic reagent with a specificity corresponding to alloantibodies detected in the patient, mixed agglutination is observed, which indicates the presence of two blood cell populations in the patient's circulation. One of them, which does not react with diagnostic antibodies, is the recipient's autologous blood cells, the other population is antigenically incompatible

Treatment of early haemolytic transfusion reactions depends mainly on the patient's condition, which must be closely monitored. It is most important to observe the clinical symptoms of the recipient and stop the blood transfusion at the right moment. Particular attention should be paid to the patient's circulation. In the event of a marked decrease in blood pressure, make-up fluids should be transfused and pressure amines should be administered. However, it is important to avoid overloading the circulation with fluids, especially in patients with heart or kidney failure. Catheterisation of the pulmonary artery helps to monitor the situation. In some cases, an exchange transfusion should be considered, bearing in mind that the haemolysis intensity depends mainly on the volume of incompatible blood transfused. For exchange transfusion, red blood cells without an antigen should be used against which the patient has developed alloantibodies. The decision to carry it out must be balanced and the course carefully monitored. It should be emphasised that in patients with an early reaction due to ABO incompatibility, exchange transfusion may reduce the risk of serious complications or death. For patients with ongoing haemorrhage choosing a blood for transfusion may be difficult. However, it should be remembered that these difficulties must not cause risk of haemorrhage. Often the way out of this situation is transfusion of O RhD negative

because autoantibodies may mimic the specificity of alloantibodies.

transfused donor cells, not yet removed from the recipient's circulation.

**10. Treatment of transfusion haemolytic reactions**

#### *Post-Transfusion Haemolytic Reactions DOI: http://dx.doi.org/10.5772/intechopen.91019*

*Human Blood Group Systems and Haemoglobinopathies*

Blood bank laboratory Direct antiglobulin test (DAT)

Clinical laboratory Complete blood count, platelet count

DIC evaluation

Blood product Confirm ABO, Rh

*Negative DAT mainly associated with HTR in ABO incompatibility.*

*Changes in laboratory indicators in haemolytic transfusion reactions [56].*

which examined a total of 690,000 blood samples, showed that the frequency of WBIT is 1 in 165. In two countries, Sweden and Finland, which have implemented national identification systems, this frequency was 1 for 1986 samples [61].

**Laboratory indicators Frequency (%)** Low haptoglobin 92 92 Positive DAT 89\* Increased bilirubin concentration medium/slow 80 The presence of haemoglobin in plasma and/or urine 88 vs. 52\*\*

*Type of laboratory tests and the location of their performance in the case of early transfusion reaction.*

Confirm other antigen types, if indicated

Post-transfusion haemolysis check

Urinalysis for haemoglobin

Confirm ABO, RH, antibody screen and identification

Serum bilirubin, creatinine, urine quantitation, coagulation profile

changes in laboratory indicators in transfusion haemolytic reactions [56].

**9.2 Tests carried out in case of suspected delayed haemolytic transfusion** 

Laboratory tests show anaemia, increased LDH and bilirubin, decreased haptoglobin and higher white blood cell counts in post-transfusion haemolytic reactions. Bilirubin concentration depends on the severity of haemolysis and liver function.

All-antibody screening for recipients is generally performed using routine testing on standard blood cells. A panel of standard cells should contain clinically important antigens in a homozygous form to detect the presence of weak antibodies. The test should be performed on serum/plasma samples taken before and after transfusion. If positive results indicate alloantibodies are present, they should be identified. Detection of a specific antigen on the donor's blood cells is the confirmation that the detected alloantibodies were responsible for the haemolytic transfusion reaction. If negative results are obtained, additional tests should be performed, for example, PTA PEG, polybrene test and PTA NaCl test. If negative results persist, the test should be repeated after a week and after 2 weeks, as in some patients, the antibodies may have been consumed to destroy transfused incompatible red blood cells. Laboratory tests that help to differentiate haemolysis include determination of free haemoglobin in the blood and urine, haptoglobin and lactate dehydrogenase (LDH) and bilirubin. While interpreting the obtained test results, it should be kept in mind that haemolysis or shortening the survival time of red blood cells can be caused by non-immunological factors, for example, adding hypotonic fluids to red blood cells, inefficient heating or freezing devices, etc. [62]. **Table 8** presents

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*\**

**Table 8.**

**Table 7.**

*\*\*IHTR vs. DHTR.*

**reaction**

Serological tests show positive DAT and the presence of all red blood cell antibodies that were not detected prior to transfusion. This means that after transfusion of red blood cells, the production of alloantibodies directed to the antigen found on the transfused blood cells occurs.

Positive DAT with anti-IgG reagents or with anti-IgG and anti-C3 reagents is generally seen as two red blood cell populations. It has been observed that in some patients, the coating of blood cells includes not only transfused, but also autologous red blood cells. Positive DAT with anti-IgG and anti-C3d reagents may persist for several months [9].

Alloantibody testing should be performed in the intermediate antiglobulin test (IAT) and enzyme test. In both methods, in addition to the reference blood cells, the patient's autologous blood cells should be included. Depending on the specificity, alloantibodies responsible for the delayed transfusion reaction activate in characteristic tests, for example, antibodies from the Rh system react in an enzymatic test, often also in anti-globulin testing. In contrast, anti-K, anti-Fya antibodies react in an anti-globulin test. Positive reactions with allogeneic blood cells are accompanied by positive auto control of the patient's red blood cells. Ness et al. [9] showed that the formation of warm autoantibodies after the onset of DHTR is relatively common. Approximately one-third of patients who were examined 25 days after the onset of the reaction presented a positive DAT due to autoantibodies with broad specificity [9]. The incidence of autoantibodies after DHTR may be even higher because autoantibodies may mimic the specificity of alloantibodies.

Usually, plasma alloantibodies are detectable at 4–7 days after the transfusion and reach maximum activity between 10 and 15 days after the transfusion. When examining recipient red blood cells using a diagnostic reagent with a specificity corresponding to alloantibodies detected in the patient, mixed agglutination is observed, which indicates the presence of two blood cell populations in the patient's circulation. One of them, which does not react with diagnostic antibodies, is the recipient's autologous blood cells, the other population is antigenically incompatible transfused donor cells, not yet removed from the recipient's circulation.
