Oਉਇਉਁ Aਔਉਃਅ Detection of anti-IgA antibodies using the particle gel immunoassay: a rapid test for increased patient safety Simona Oltean, Andreea Epure, Karin Lindström, Cecilia Pardi Transfusion Centre, Department of Clinical Immunology and Transfusion Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
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Background. Patient safety is a major issue in transfusion medicine and commands continuous efforts to develop valid control methods aiming to avoid serious transfusion-related complications. Anti-IgA antibodies can cause anaphylactic transfusion reactions in IgA-deficient individuals. Since standard quantitative methods for anti-IgA measurement require considerable time to be performed, in an emergency situation it can be a challenge to prevent or to quickly interpret and manage acute transfusion reactions suspected to be a consequence of anti-IgA. The purpose of this study was to test and validate at our transfusion centre a rapid assay for the identification of patients with anti-IgA antibodies. Materials and methods. Forty-six samples (6 from healthy controls and 40 from IgA-deficient patients) were collected. Sera were analysed blindly by three different clinical laboratory technologists using two DiaMed particle gel immunoassays (ID-PaGIA) for IgA deficiency and for antibodies to IgA . The results were subsequently checked with the results of a fluorescence enzyme immunoassay conducted in the reference immunology laboratory. Results. The ID-PaGIA had a sensitivity of 91.7% and specificity of 97.1% for the IgA deficiency test. With regards to the detection of anti-IgA antibodies, the sensitivity was 89.3% and the specificity 100%. The reproducibility of the test was 100%. Discussion. The ID-PaGIA screening assays are suitable for the investigation of transfusion-related anaphylactic reactions in a routine blood bank laboratory. Although the gel card technique does not quantify the level of anti-IgA antibodies, it is readily available, providing an effective and simple method for the diagnosis of anti-IgA related anaphylaxis and guidance for the appropriate transfusion practice in an emergency.
Introduction
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Keywords: IgA deficiency, anti-IgA antibodies, anaphylactic transfusion reaction, particle gel immunoassay, transfusion urgency.
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Emergency transfusion of blood components in individuals with IgA deficiency is both a medical and logistical challenge. If not properly diagnosed, patients with anti-IgA antibodies may develop severe transfusion reactions and anaphylaxis when receiving blood components containing even minute amounts of IgA1. The logistical difficulties are due to both the technically challenging diagnostic tests and the difficulty in providing adequate amounts of suitable blood components when the need for transfusion is urgent. The rapid recognition of IgA-related transfusion reactions and discrimination from other transfusion-related allergic reactions are essential elements for successful patient management2. Besides increasing patient safety, an accurate diagnosis would justify the use of rare blood components such as washed red blood cells or plasma from IgA-deficient donors.
The current diagnostic tests for anti-IgA antibodies are based on time-consuming and labour-intensive methods. Haemagglutination and flow cytometry are reliable but technically demanding and timeconsuming while the immunoassays (enzyme-linked immunosorbent assay, radioimmunoassay) are less sensitive and thus less reliable3. A new qualitative method used for detecting IgA deficiency and the presence or absence of anti-IgA antibodies is the particle gel immunoassay (PaGIA). The method is rapid and technically straightforward yet only a limited number of publications are available on the use of this method for the detection of IgA deficiency and anti-IgA antibodies4. Thus, a direct comparison between this more recent approach and other established methods is lacking. Such results could provide essential information on the efficiency, limitations and potential sources of error of these methods. Blood Transfus 2014; 12: 334-9 DOI 10.2450/2014.0219-13 © SIMTI Servizi Srl
334 All rights reserved - For personal use only No other uses without permission
Evaluation of anti-IgA in emergencies
The study took place during the period from September 2010 to February 2011. Serum samples Serum samples from 40 patients previously tested for IgA deficiency and the presence of anti-IgA antibodies (by FEIA) were analysed. Serum samples from six blood donors were used as healthy controls after testing by FEIA for total IgA and anti-IgA levels. The samples were frozen after running by FEIA, stored at −20 °C and thawed the day we analysed them by PaGIA.
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The standard diagnostic method for determining IgA deficiency The reference laboratory used enzyme fluoroimmunoassays from Phadia which were carried out on an automated ImmunoCAP 250 analyser (Thermo Fisher Scientific/Phadia, Uppsala, Sweden) as highly sensitive immunoassays to quantify serum IgA and IgG anti-IgA antibodies. The assay ranges established by the immunology laboratory were between 0 and 0.8 mg/dL for Ig A and between 0 and 60,000 units/mL for anti-IgA and were based on the results of multiple assays and statistical averages. IgA values
TI S
er v
iz i
Sr l
Background. Patient safety is a major issue in transfusion medicine and commands continuous efforts to develop valid control methods aiming to avoid serious transfusion-related complications. Anti-IgA antibodies can cause anaphylactic transfusion reactions in IgA-deficient individuals. Since standard quantitative methods for anti-IgA measurement require considerable time to be performed, in an emergency situation it can be a challenge to prevent or to quickly interpret and manage acute transfusion reactions suspected to be a consequence of anti-IgA. The purpose of this study was to test and validate at our transfusion centre a rapid assay for the identification of patients with anti-IgA antibodies. Materials and methods. Forty-six samples (6 from healthy controls and 40 from IgA-deficient patients) were collected. Sera were analysed blindly by three different clinical laboratory technologists using two DiaMed particle gel immunoassays (ID-PaGIA) for IgA deficiency and for antibodies to IgA . The results were subsequently checked with the results of a fluorescence enzyme immunoassay conducted in the reference immunology laboratory. Results. The ID-PaGIA had a sensitivity of 91.7% and specificity of 97.1% for the IgA deficiency test. With regards to the detection of anti-IgA antibodies, the sensitivity was 89.3% and the specificity 100%. The reproducibility of the test was 100%. Discussion. The ID-PaGIA screening assays are suitable for the investigation of transfusion-related anaphylactic reactions in a routine blood bank laboratory. Although the gel card technique does not quantify the level of anti-IgA antibodies, it is readily available, providing an effective and simple method for the diagnosis of anti-IgA related anaphylaxis and guidance for the appropriate transfusion practice in an emergency.
Introduction
SI
M
Keywords: IgA deficiency, anti-IgA antibodies, anaphylactic transfusion reaction, particle gel immunoassay, transfusion urgency.
©
Emergency transfusion of blood components in individuals with IgA deficiency is both a medical and logistical challenge. If not properly diagnosed, patients with anti-IgA antibodies may develop severe transfusion reactions and anaphylaxis when receiving blood components containing even minute amounts of IgA1. The logistical difficulties are due to both the technically challenging diagnostic tests and the difficulty in providing adequate amounts of suitable blood components when the need for transfusion is urgent. The rapid recognition of IgA-related transfusion reactions and discrimination from other transfusion-related allergic reactions are essential elements for successful patient management2. Besides increasing patient safety, an accurate diagnosis would justify the use of rare blood components such as washed red blood cells or plasma from IgA-deficient donors.
The current diagnostic tests for anti-IgA antibodies are based on time-consuming and labour-intensive methods. Haemagglutination and flow cytometry are reliable but technically demanding and timeconsuming while the immunoassays (enzyme-linked immunosorbent assay, radioimmunoassay) are less sensitive and thus less reliable3. A new qualitative method used for detecting IgA deficiency and the presence or absence of anti-IgA antibodies is the particle gel immunoassay (PaGIA). The method is rapid and technically straightforward yet only a limited number of publications are available on the use of this method for the detection of IgA deficiency and anti-IgA antibodies4. Thus, a direct comparison between this more recent approach and other established methods is lacking. Such results could provide essential information on the efficiency, limitations and potential sources of error of these methods. Blood Transfus 2014; 12: 334-9 DOI 10.2450/2014.0219-13 © SIMTI Servizi Srl
334 All rights reserved - For personal use only No other uses without permission
Evaluation of anti-IgA in emergencies
The study took place during the period from September 2010 to February 2011. Serum samples Serum samples from 40 patients previously tested for IgA deficiency and the presence of anti-IgA antibodies (by FEIA) were analysed. Serum samples from six blood donors were used as healthy controls after testing by FEIA for total IgA and anti-IgA levels. The samples were frozen after running by FEIA, stored at −20 °C and thawed the day we analysed them by PaGIA.
©
SI
M
TI S
er v
The standard diagnostic method for determining IgA deficiency The reference laboratory used enzyme fluoroimmunoassays from Phadia which were carried out on an automated ImmunoCAP 250 analyser (Thermo Fisher Scientific/Phadia, Uppsala, Sweden) as highly sensitive immunoassays to quantify serum IgA and IgG anti-IgA antibodies. The assay ranges established by the immunology laboratory were between 0 and 0.8 mg/dL for Ig A and between 0 and 60,000 units/mL for anti-IgA and were based on the results of multiple assays and statistical averages. IgA values
