IMMUNOHEMATOLOGY: Identification and evaluation of false-negative antibody screens

A comparison of three column agglutination tests for red blood cell alloantibody identification

Objective

Commercial kits of column tests for pre-transfusion testing have progressively replaced conventional tube tests in most laboratories. Aim of this study was to compare three commercial test cell panels for the identification of irregular red blood cell (RBC) alloantibodies. Overall, 44 samples with a positive indirect antiglobulin test (IAT) by routine testing were used for comparison of following panels: Ortho RESOLVE^® panelC (Ortho Clinical Diagnostics (OCD), Milan, Italy), ID-DiaPanel(-P) (Bio-Rad Laboratories, CA, USA) and Identisera Diana(P) (Grifols, Barcelona, Spain). Column agglutination techniques were used, with microtubes containing either microgel (Bio-Rad/Grifols) or glass bead microparticles (Ortho).

Results

Alloantibody identification was possible in 38 samples, of which identical identification was shown in 33 samples by all methods. The remaining samples showed differences between certain methods, with the gel card system being superior to the glass card system for analyzing stored samples Considering that not all samples were evaluated in all three methods, the concordance rate reached 100% between Bio-Rad and Grifols, 90.5% between Bio-Rad and OCD, 86.5% between OCD and Grifols and 90.5% between all methods. Although differences in sensitivities were seen for specific antibodies, the three methods showed comparable performance for the identification of RBC alloantibodies.

Red Cell Alloantibody Screening: Comparative Analysis of Three Different Technologies

Background

The detection of irregular antibody is a critical issue in the management of red blood cell transfusion according to the Type & Screen (T&S) practice. In order to implement the T&S procedure at our blood bank, we compared three different automated analyzers based on column agglutination technique (CAT) or solid phase red cell adherence assay (SPACA) methods.

Methods

Pre-transfusion antibody screening was performed in 986 patients candidate to elective surgery at low risk for red blood cell transfusion. We tested the following kits: the three-cell panel micro-CAT system ID-DiaCell I-II-III (DiaMed), the four-cell panel solid-phase system Capture-R Ready Screen-4 (Immucor), and the four-cell panel micro-CAT system Serascan Diana-4 (Grifols). Positive results were further investigated using corresponding identification panels, and discrepant results were investigated with all the antibody identification systems.

Results

Among 986 samples, we observed 967 concordant negative results (98.1%), 8 concordant positive results (0.8% of cases), and 11 discrepant results (1.1%). Among discrepant samples, an alloantibody could been identified in two patents (anti-M, detected by Serascan Diana-4 and ID-DiaCell I, II, III; anti-Kp^a, detected by Capture-R Ready Screen-4 and Serascan Diana-4).

Conclusion

Among the evaluated technologies, the four-cell panel micro-CAT system displayed the highest sensitivity and specificity with an optimal negative predictive value. These features might be relevant to the routine implementation of the T&S transfusion strategy.

Alloimmunization in multitransfused liver disease patients: Impact of underlying disease

Introduction:

Transfusion support is vital to the management of patients with liver diseases. Repeated transfusions are associated with many risks such as transfusion-transmitted infection, transfusion immunomodulation, and alloimmunization.

Materials and Methods:

A retrospective data analysis of antibody screening and identification was done from February 2012 to February 2014 to determine the frequency and specificity of irregular red-cell antibodies in multitransfused liver disease patients. The clinical and transfusion records were reviewed. The data was compiled, statistically analyzed, and reviewed.

Results:

A total of 842 patients were included in our study. Alloantibodies were detected in 5.22% of the patients. Higher rates of alloimmunization were seen in patients with autoimmune hepatitis, cryptogenic liver disease, liver damage due to drugs/toxins, and liver cancer patients. Patients with alcoholic liver disease had a lower rate of alloimmunization. The alloimmunization was 12.7% (23/181) in females and 3.17% (21/661) in males. Antibodies against the Rh system were the most frequent with 27 of 44 alloantibodies (61.36%). The most common alloantibody identified was anti-E (11/44 cases, 25%), followed by anti-C (6/44 cases, 13.63%).

Conclusion:

Our findings suggest that alloimmunization rate is affected by underlying disease. Provision of Rh and Kell phenotype-matched blood can significantly reduce alloimmunization.

Alloimmunization screening after transfusion of red blood cells in a prospective study

Background

Several irregular red blood cell alloantibodies, produced by alloimmunization of antigens in transfusions or pregnancies, have clinical importance because they cause hemolysis in the fetus and newborn and in transfused patients.

Objective

a prospective analysis of patients treated by the surgical and clinical emergency services of Hospital de Clínicas of the Universidade Federal do Triângulo Mineiro (HC/UFTM), Brazil was performed to correlate alloimmunization to clinical and epidemiological data.

Methods

Blood samples of 143 patients with initial negative antibody screening were collected at intervals for up to 15 months after the transfusion of packed red blood cells. Samples were submitted to irregular antibody testing and, when positive, to the identification and serial titration of alloantibodies. The Fisher Exact test and Odds Ratio were employed to compare proportions.

Results

Fifteen (10.49%) patients produced antibodies within six months of transfusion. However, for 60% of these individuals, the titers decreased and disappeared by 15 months after transfusion. Anti-K antibodies and alloantibodies against antigens of the Rh system were the most common; the highest titer was 1:32 (anti-K). There was an evident correlation with the number of transfusions.

Conclusions

Given the high incidence of clinically important red blood cell alloantibodies in patients transfused in surgical and clinical emergency services, we suggest that phenotyping and pre-transfusion compatibilization for C, c, E, e (Rh system) and K (Kell system) antigens should be extended to all patients with programmed surgeries or acute clinical events that do not need emergency transfusions.