False positive Kleihauer tests and unnecessary administration of anti-D immunoglobulin

This obstetric case shows two false negative Kleihauer tests and two persistently positive Kleihauer tests leading to unnecessary administration of anti-D immunoglobulin. A diagnosis of hereditary persistence foetal haemoglobin (HPFH) was only confirmed by access to flow cytometry making use of both anti-HbF and anti-D labels. The case highlights the importance of a high index of clinical suspicion for HPFH and the importance of access to flow cytometry estimation of minor RhD red cell populations postnatally in RhD-negative mothers.

The importance of antibodies against low-incidence RBC antigens in complete and abbreviated cross-matching

BACKGROUND

It is common practice to perform an antiglobulin cross-match only when unexpected RBC alloantibodies are present, to detect antibodies against additional RBC antigens. In this study, the incidence of unexpected antibodies to low-incidence antigens (Ab-LIA) over a period of 23 years was investigated.

STUDY DESIGN AND METHODS

Records of RBC antibodies and the accompanying transfusion history from 1978 through 2000 was retrospectively examined. Complete cross-matches were performed for all RBC transfusions before 1991. As of 1991, the type-and-screen policy was applied. To study the incidence of anti-Wra, a prospective study was conducted on sera from 462 patients sent to the transfusion laboratory and 486 blood donors.

RESULTS

The records of 1795 patients containing 2257 RBC antibodies were examined. In 89 patients, a total of 94 Ab-LIAs was found. Anti-Wra was the most frequently encountered Ab-LIA. Thirty-nine patients had Ab-LIA in combination with other antibodies, 20 of which were autoantibodies. Eighty percent of these Ab-LIA were found at the first positive antibody screening test. Fifty-one solitary Ab-LIA were found in 50 patients, 37 during antibody screening tests, and 14 after positive complete cross-matches conducted before 1991. After an RBC antibody was detected, 664 patients received a total of 7792 RBC transfusions. Since the introduction of the type-and-screen policy, only one anti-Wra has been discovered during complete cross-matching. No transfusion reactions due to Ab-LIA were reported during the study period. In the prospective study, 12.3 percent of patients and 4.3 percent of blood donors had anti-Wra.

CONCLUSIONS

Although Ab-LIAs are found coincidentally in the sera of only 2 to 3 percent of patients with other RBC antibodies, they are formed often. Because we found no difference in serologic incompatibility, due to Ab-LIAs, between patients with and without other blood group antibodies, we conclude that blood can be transfused safely to patients without performing a complete cross-match.

Application of Taylor vortices in hemocompatibility investigations

BACKGROUND

Artificial organs, implants and extracorporeal circulation affect the physiological flow characteristics of blood as a liquid organ. These artificial systems consist of a wide variety of biomaterials with different geometries and, therefore, with their own flow properties. Secondary flow also occurs in extra--as well as in intracorporeal circulation.

METHODS

In order to investigate the influence of vortical flow conditions a modified Taylor-Couette system was introduced. It consisted of two coaxial cylinders whose surfaces were the target of investigation. The annular gap was filled with donor blood shear and secondary flows were produced by rotating the inner cylinder. Platelet activation and protein adsorption were investigated as markers for thrombogenicity.

RESULTS

At shear rates high enough to establish stable Taylor vortices (G > or = 550 s(-1)) significant differences between vortical Taylor flow and steady laminar flow were detected. At shear rates of G > or = 550 s(-1) laminar flow caused a significantly higher platelet drop and PF4 release when compared to Taylor vortex flow. Also protein adsorption per square unit was significantly higher for laminar flow.

CONCLUSIONS

Based on the present data we conclude that vortical flow patterns lead to an accumulation of platelets and plasma proteins in the vortex center and therefore to a decreased probability of contact between platelets and material surfaces. It can be concluded that a preactivation of the platelets circulating in extracorporeal circuits can be manifested downstream in other geometrical configurations and flow conditions.

[Examination for prevent of blood transfusion errors]

Human error has identified as a major source of ABO incompatibility-related transfusion fatalities. Frequency of ABO-incompatible transfusion has been reported to range from 2.5 to 253 per 100,000 transfusion units. Transfusion error has developed various occasions, for example, wrong specimen and patients, specimen exchange and mistake of ABO compatibility test. In laboratory examination, many errors were occurred during night shift, because it was necessary to established the examination system. We discussed about examination for prevent of blood transfusion errors.

[Prevalence of immunohematologic tests at birth and the incidence of hemolytic disease in the newborn]

The administration of anti-D globulin to the mothers has decreased the incidence of Rh hemolytic disease but the improvement of technologic assays has made it possible to identify several hemolytics diseases of the newborn.

BACKGROUND

To identify the prevalence of immunohematologic tests demonstrated by indirect (IC), direct (DC) and elution tests; to identify the incidence of hemolytic disease and its treatment (phototherapy and/or exchange transfusion) in neonates with hemolytic disease. This is a retrospective cohort-study performed from January 1st 1996 to July 1st 1998.

METHODS

This is a descriptive study of the immunohematologic profile of 1698 mothers and their offsprings, as risk factors for developing hemolytic disease. The inclusion criteria were the positivity of the indirect (IC) and direct (DC) Coombs tests and elution tests. Based on the inclusion criteria three group of infants were analyzed: Group I was composed of 149 offsprings of Coombs-positive mothers (IC+) with antibodies associated with neonatal hemolytic disease. This group was further divided into two groups: Group I-A (IC+DC+) was composed of 83 Coombs-positive offsprings (DC+) of Coombs-positive mothers (IC+) and Group I-B (IC+DC-) was composed of 66 Coombs-negative offsprings (DC-) of Coombs-positive mothers (IC+); Group D was composed of 736 Coombs-positive offspring's of Coombs-negative mothers (IC-); and Group E was composed of 807 Coombs-negative and elution-positive offspring's of Coombs-negative mothers.

RESULTS

This study shown that the overall prevalence of immunohematologic tests associated with hemolytic disease was 9.07% (3212/35429), 0.43% (154/35429) among offsprings of Coombs-positive mothers, 4.10% (1453/35429) among Coombs-positive infants, and 4.53% (1605/35429) among elution-positive infants. The overall incidence of hemolytic disease was 36.23% (613/1692), 33.56% (50/149) among offspring's of Coombs-positive mothers, 44.43% (327/736) among Coombs-positive infants, and 29.24% (236/807) among elution-positive infants. The overall incidence of phototherapy among infants with hemolytic disease was 36.23% (613/1692), 49.40% (41/83) in group I-A (IC+DC+), 13.64% (9/66) in group I-B(IC+DC-), 44.43% (327/736) in group D, and 29.24% (236/807) in group E. The overall incidence of exchange transfusion among infants with hemolytic disease was 0.88% (15/1692), 14.46% (12/83) in group I-A (IC+DC+), 0% (0/66) in group I-B (IC+DC-), 0.27% (2/736) in group D, and 0.12% (1/807) in group E.

CONCLUSIONS

The results of this study allowed us to conclude that the overall prevalence of immunohematologic tests associated with hemolytic disease was 9.07% (3212/35429) and the overall incidence of hemolytic disease was 36.23% (613/1692) in this study-group. The highest incidences of hemolytic disease and phototherapy were observed among Coombs-positive offsprings of Coombs-positive mothers.

Prophylactic antigen-matched donor blood for patients with warm autoantibodies: an algorithm for transfusion management

BACKGROUND

Patients with warm autoantibodies are at high risk for delayed hemolytic transfusion reactions due to the presence of alloantibodies. To provide blood safe for transfusion and to avoid adsorption studies in some cases, the provision of prophylactic antigen-matched donor blood where feasible for patients with warm autoantibodies is advocated.

STUDY DESIGN AND METHODS

Twenty consecutive adult patients with warm autoantibodies (January 1999 to February 2000) received chronic RBC transfusions by use of this protocol: the serology consistent with warm autoantibodies was confirmed; the alloantibodies were identified; the complete phenotype was determined (i.e., C, E, c, e, K, Jk(a), Jk(b), Fy(a), Fy(b), S, and s); and prophylactic antigen-matched (i.e., donor RBCs matched with the patient's phenotype), WBC-reduced donor RBCs were provided for transfusion. On subsequent admissions, samples were evaluated by panel studies and DATs. If the serology remained consistent with previous findings, prophylactic antigen-matched, WBC-reduced RBCs were transfused without further testing.

RESULTS

Eight of 20 (40%) patients had existing, clinically significant alloantibodies. In 12 of 20 (60%) patients, a phenotype was determined and the patients received transfusion of a total of 149 prophylactic antigen-matched RBC units (mean, 15 units per patient) precluding adsorption studies on 51 pretransfusion samples. In 8 of 20 (40%) cases (2 with alloantibodies), phenotypes were indeterminant, necessitating differential allogeneic adsorption studies on 39 samples before transfusion of 144 RBC units (mean, 18 units per patient).

CONCLUSIONS

Determining complete phenotypes should be a routine component of the serologic evaluation of patients with warm autoantibodies. Our algorithm for providing prophylactic antigen-matched RBCs to these patients when a complete phenotype can be determined provides flexibility in their transfusion management while maintaining safety and circumvents or simplifies pretransfusion adsorption studies.

Anti-Vel reactivity diminished by adsorption with rabbit RBC stroma

BACKGROUND

An anti-Vel, nearly missed in antibody identification studies, and the effect of a commercially available rabbit RBC stroma (RESt, Immucor) adsorptions on eight anti-Vel sera are reported. Anti-Vel is an antibody to an antigen of high prevalence.

CASE REPORT

A 48-year-old woman with chronic vaginal bleeding presented with a Hct of 14.7 percent. The transfusion service was not informed of her history of anti-Vel when she was transferred from another institution. Studies performed on an emergency request for transfusion were interpreted as a cold autoantibody as adsorption with a commercial source of RESt eliminated the reactivity. Stored anti-Vel sera were tested by titration studies before and after adsorption with commercial RESt.

RESULTS

Serum from the index case did not react after adsorption with RESt at the transfusion service. Studies with the stored anti-Vel indicated antibody adsorption with four of four samples at immediate spin (IS) and room temperature (RT) phases, four of eight samples at 37 degrees C in albumin (ALB) phase, and four of eight samples at ALB-IgG-AGT phase. Variations in antibody reactivity were observed in the samples tested, but RESt adsorption diminished antibody reactivity in most samples. All eight stored sera demonstrated some reactivity in at least one phase after adsorption with RESt.

CONCLUSION

Anti-Vel was completely or partially adsorbed by RESt. Caution should be used when interpreting cold agglutinins with this method. The manufacturer warns that uncommon alloantibodies may be adsorbed.

[Diagnostic and therapeutic proceedings in pregnancies with blood group incompatibility: A retrospective analysis over 30 years]

PURPOSE

To examine the development during the past 30 years of diagnostic and therapeutic procedures in pregnancies with blood group incompatibility.

PATIENTS AND METHODS

We evaluated 193 pregnancies with maternal red blood alloimmunisation treated at our hospital. At least one amniotic fluid spectrophotometry was performed.

RESULTS

We observed a reduced average age of the patients, a reduced parity and an increase in the number of amniotic fluid examinations per pregnancy in the course of time. Amniotic fluid examinations tended to be performed earlier in pregnancy. Gestational time was reduced, the rate of spontaneous vaginal deliveries remained unchanged. The proportion of anti-D-alloimmunisation decreased in relation to other antigens and the severity of the cases increased (assessed according to the findings of the spectrophotometric amniotic fluid examinations performed while using the semiquantitative method of Liley). The haemoglobin values of the newborn, without intrauterine transfusions, were unchanged and the number of intrauterine deaths decreased. The rate of postnatal transfusions decreased dramatically, whereas the rate of phototherapeutic approaches increased.

CONCLUSION

The spectrum of the antigens causing fetal haemolytic disease has changed during the last 30 years and so have the diagnostic and therapeutic procedures.

[Acute hemolytic transfusion reaction]

Alloogenous blood and/or corresponding haemoproduct transfusion is an efficient and relatively safe supportive treatment. Despite the fact that pre transfusion investigation of both patients and donors ensure high degree of safety of this type of treatment, occurrence of adverse haemotherapy effects is possible and often unpredictable. Acute haemolytic transfusion reaction occur as a consequence of immune conflict between red blood cell membrane agents and specific antibodies present in plasma. Since it is impossible to completely avoid the occurrence of transfusion reactions, wherein acute transfusion haemolytic reaction present a serious, possibly life threatening complication, it is an imperative to continue to improve the knowledge on pathogenesis mechanisms leading to complications associated with these reaction and to define the most efficient therapeutical modalities.

[Neonatal alloimmune thrombocytopenia with hemorrhagic infarction of the right hemisphere]

Alloimmune thrombocytopenia is the most common cause of severe thrombocytopenia (< 20 000/microliter) in otherwise healthy neonates. The diagnosis is usually made in the diagnostic workup of neonatal hemorrhage. If diagnosis and therapy are delayed the consequences for the affected child can be deleterious. Case report of a full-term neonate with the clinical symptoms of severe hemorrhage and hemorrhagic infarction of the right hemisphere due to neonatal alloimmune thrombocytopenia. While the plasmatic coagulation parameters were unaffected, we detected severe neonatal thrombocytopenia and anemia and identified alloimmune antibodies against the child's thrombocytes in the mother's serum. The antibodies were specific against the platelet antigen HPA-1a. Transfusion of HPA-1a-negative thrombocytes stabilized the platelet count. Anemia was treated by erythrocyte transfusion. Unfortunately, the patient exhibited, most likely intrauterine, intracranial hemorrhage and infarction of the right hemisphere, the most dreaded complication of neonatal alloimmune thrombocytopenia. The identification of severe thrombocytopenia causing the hemorrhage allowed us to start substituting thrombocytes without any delay. The previous diagnosis of alloimmune thrombocytopenia should lead to monitoring a subsequent pregnancy in a specialized unit allowing fetal blood sampling and intrauterine thrombocyte substitution if necessary.This case report exemplifies the symptoms and treatment of neonatal alloimmune thrombocytopenia. The differential diagnosis for a neonate showing clinical signs of hemorrhage should include alloimmune thrombocytopenia which can then be treated adequately. The diagnosis should also lead to careful monitoring of subsequent pregnancies.

[Problem-solving in immunohematology: direct compatibility laboratory test ]

Cross-matching between the serum of a patient and the red blood cells to be transfused is most important for the prevention of hemolytic transfusion reactions in allo-immunized or new-born patients found positive with direct antiglobulin test. Cross-matching is a time-consuming and complex laboratory test. In order to obtain valid results, it is necessary to abide by some technical rules detailed in this article. The choice of the blood units to be cross-matched depends on the patient's clinical story and on the specificity of anti-erythrocyte antibodies present in the serum. The identification and the management of most frequent difficulties met by using the cross-match technique are discussed hereby.

RHD positive haplotypes in D negative Europeans

BACKGROUND

Blood group genotyping is increasingly utilized for prenatal diagnosis and after recent transfusions, but still lacks the specificity of serology. In whites, the presence of antigen D is predicted, if two or more properly selected RHD-specific polymorphism are detected. This prediction must fail, if an antigen D negative RHD positive allele is encountered. Excluding RHDpsi and CdeS frequent only in individuals of African descent, most of these alleles are unknown and the population frequency of any such allele has not been determined.

METHODS

We screened 8,442 antigen D negative blood donations by RHD PCR-SSP. RHD PCR positive samples were further characterized by RHD exon specific PCR-SSP or sequencing. The phenotype of the identified alleles was checked and their frequencies in Germans were determined.

RESULTS

We detected 50 RHD positive samples. Fifteen samples harbored one of three new Del alleles. Thirty samples were due to 14 different D negative alleles, only 5 of which were previously known. Nine of the 14 alleles may have been generated by gene conversion in cis, for which we proposed a mechanism triggered by hairpin formation of chromosomal DNA. The cumulative population frequency of the 14 D negative alleles was 1:1,500. Five samples represented a D+/- chimera, a weak D and three partial D, which had been missed by routine serology; two recipients transfused with blood of the D+/- chimera donor became anti-D immunized.

CONCLUSION

The results of this study allowed to devise an improved RHD genotyping strategy, the false-positive rate of which was lower than 1:10,000. The number of characterized RHD positive antigen D negative and Del alleles was more than doubled and their population frequencies in Europe were defined.

Treatment of severe thrombocytopenia in alloimmunized, transfusion-refractory patients

A significant proportion of patients with hematologic malignancies who are exposed to multiple transfusions will develop alloantibodies to platelet human leukocyte antigens (HLA), resulting in poor responses to subsequent platelet transfusions. Transfusion of HLA-identical platelets is an effective method of platelet support in these patients, but perfectly HLA-matched platelets are often not available. In this paper, we review the recent literature on platelet transfusion support in alloimmunized individuals and illustrate alternative management strategies with cases from our own practice.

Transfusion reactions

Blood components are indicated in a wide variety of disease states. Although most transfusion therapies are administered uneventfully, there are a number of potential adverse transfusion reactions, some of which can assume serious dimensions. These reactions could occur during or even days after a transfusion. A brief description of the adverse effects of transfusion therapy has been outlined in this review. The etiopathogenesis, recognition and treatment of the adverse transfusion reactions have been highlighted. It is imperative that each transfusion of blood components has components be monitored carefully. Prompt recognition of an adverse event and early institution of remedial measures would help in decreasing transfusion related morbidity and mortality.

[Feto-maternal incompatibility due to the platelet specific antigens: frequency, diagnosis and general rules of management]

In this review actual problems of the frequency, diagnosis and general rules of management of the neonatal alloimmune thrombocytopenia (NAIT) due to platelet antigens are presented.

[Rh feto-maternal incompatibility after the 25 year long immunoprophylaxis]

Results of antibody investigations during pregnancy in 348,040 women were summared. Immune alloantibody were stated in 3053 women (0.9%): in 2437 anti-D (1.6% of Rh negative) and in 606 other immune antibodies. The reasons of the D antigen immunization were analysed. Anti-D activity by chemiluminescence test (CLT) in 45 women, qualified to cordocentesis, were presented. The results compared to the fetal anaemia indicated that in women with high titer (32 or higher), CLT could diminish invasive diagnostics.

[Analytical validation in erythrocyte immunohematology]

In a transfusional or foeto-maternal context, hemolysis by incompatibility due to anti-erythrocyte antibodies (regular or irregular) remains the most frequent and most serious immunological risk in the receiver. In order to prevent this risk, a number of actions must be taken, such as the realization of the immunohematologic analyses for which the methodological practices have been legislated because of their serious clinical consequences. Several elements play a role in the reliability of the analyses and their results: the selection of the reagents and their validation in the routine technique used; the validation of reception; the controls involved in secondary preparations (e.g., blood cells reagent); and the daily internal controls. All this requires the choice of adapted controls and the management of possible anomalies.

Errors in interpreting the pretransfusion bedside compatibility test: an experimental study

BACKGROUND AND OBJECTIVE

Analysis of reports of incidents, involving ABO incompatibility suggests that the main problem is poor interpretation of the pretransfusion bedside compatibility test (PBCT). We studied sources of error as experienced by nurses as to the blood groups of donor blood and of the recipient.

MATERIALS AND METHODS

According to their seniority in the profession and on the ward, 48 nurses were randomly selected from four transfusion sectors of the University Hospital of Grenoble, France. Each nurse interpreted 24 photos of PBCTs, including some with procedural irregularities, and was asked to assess the compatibility of the blood types of the donor and the recipient. At random, half the nurses were provided with a diagram to facilitate interpretation.

RESULTS

The overall frequency of errors was 39.8%. Errors were fewer when the tests were interpreted as compatible (7.3%) or incompatible (6.3%), and when the nurse had been in the profession between 3 and 5 years and in the ward less than 3 years (25.5%), or worked in hematology (34.7%) or anesthesia (36.5%). Use of the diagram limited the number of errors, provided the test was interpretable (22.2%).

CONCLUSION

PBCTs cannot be considered a valid safety procedure. We need other, more effective methods to reduce the risk of incompatibility accidents.

ABO hemolytic disease of the newborn: a unique constellation of findings in siblings and review of protective mechanisms in the fetal-maternal system

Two siblings born 6 years apart presented with similar findings of hepatosplenomegaly, dermal hematopoiesis, hemoglobinuria, and increased platelet consumption, but only moderate anemia and normal serum bilirubin. ABO incompatibility was identified, and other causes were excluded. A review of the current understanding of mechanisms that promote and prevent antibody-mediated hemolysis in the fetus is reviewed. Due to the low ratio of observed to expected significant clinical events among ABO incompatible mother-infant pairs, and the multiplicity of mechanisms that diminish hemolysis, we speculate that severe ABO hemolytic disease of the newborn occurs when there is a specific failure in one of these preventive mechanisms.