LETTERS TO THE EDITOR
Antibodies titration for immunized pregnant women: conventional tube test or gel microcolumn assay Antibody titration and titer monitoring are required throughout pregnancy. Different studies have been published comparing RBC alloantibody titration by gel microcolumn assay (GMA) with conventional tube test (CTT).1-3 Recently Finck and coworkers1 have compared six specificities of alloantibodies identified during routine transfusion. They concluded that GMA was comparable to CTT. In our laboratory, we used gel cards for blood grouping, antibody screening and identification, compatibility testing, and the direct antiglobulin test. Gel tests are easy to use, allow an objective reading of agglutination, and have a stable end point. We titrated 136 antibodies from immunized pregnant women using the two methods: conventional tube and gel card. Titration was performed using serial twofold dilutions in normal saline in test tubes and dilutions were tested in parallel for both tests. Red blood cells (RBCs) were washed three times in normal saline and resuspended to a final concentration of 4% for tube and 0.8% for gel. Briefly, each serum dilution and RBCs were dispensed into each tube or card (Scan gel anti-IgG, Bio-Rad, Marnes La Coquette, France) and incubated. Tubes were incubated at 37°C for 30 minutes and gel cards at 37°C for 15 minutes. After three washings, antiglobulin was added, the tubes were centrifuged, and the agglutination was read. Gel cards do not require washing and addition of antiglobulin sera. The standard anti RH1 (Diagast, Loos, France) with a known titer (512) was tested in each series. Titration is a semiquantitative method and a difference of one titer was accepted.4 The difference in titers between the two methods is shown in Table 1. A total of 136 alloimmunized obstetric patients were included and titrations were performed on 11 specificities. For 53 (39%) antibody titrations, the two methods gave similar results or within one titer; for 31 (23%) titrations, there was a difference of two titers, and for 52 (38%), three or more titers. A total of 188 were performed with the standard anti-RH1 IgG. GMA results were the same as CTT results in 41 (22%) samples and there was a difference of two titers for 122 (65%) samples and three titers or more for 25 (13%) samples. In the study by Finck and colleagues,1 GMA and CTT generated similar results or within one titer for 42 of 48 (85%) patients but the assays were performed with antibodies generated after transfusion and none from obstetric patients. GMA titers in our study tend to be higher than the tube titers. Based on these data, it is currently difficult to accept the GMA to monitor immunized pregnant women. 1200
TRANSFUSION Volume 54, April 2014
TABLE 1. The difference in titers between GMA and CTT Antibody specificity Anti-D Anti-D + anti-C Anti-D + anti-E Anti-C Anti-E Anti-c Anti-Cw Anti-Kell Anti-S Anti-Jka Anti-Fya Total Anti-RH1 IgG
Titers no difference, Number 7 14 7 4 39 32 7 8 12 3 3
Titers major difference,
2
3 or more
0–1 3 0 2 3 21 8 3 4 5 1 3
136 188
Titers minor difference,
53 (39%) 41 (22%)
1 3 0 1 6 10 3 4 1 2 0 31 (23%) 122 (65%)
3 11 5 0 12 14 1 0 2 0 0 52 (38%) 25 (13%)
CONFLICT OF INTEREST The authors report no conflicts of interest or funding sources.
Alexis Duez, MD1 e-mail: [email protected] Françoise Flourié, MD2 Olivier Garraud, MD, PhD3 1 Laboratoire d’Hématologie Hôpital Nord, CHU de Saint Etienne 2 Laboratoire d’Immuno-Hématologie 3 EFS Auvergne – Loire Saint Etienne, France
REFERENCES 1. Finck R, Deguzman-Lui C, Teng S, et al. Comparison of a gel microcolumn assay with the conventional tube test for red blood cell alloantibody titration. Transfusion 2013;53:811-5. 2. Novaretti MC, Jens E, Pagliarini T, et al. Comparison of conventional tube test with Diamed gel microcolumn assay for anti-D titration. Clin Lab Haematol 2003;25:311-5. 3. Thakur MK, Marwaha N, Kumar P, et al. Comparison of gel test and conventional tube test for antibody detection and titration in D-negative women: study from a tertiary-care hospital in North India. Immunohematology 2010;26:174-7. 4. Roback JD, Grossman BJ, Harris T, Hillyer CD. Technical manual. 17th ed. Bethesda (MD): American Association of Blood Banks; 2011.
Wrong blood in tube error: first study on donor blood samples Although the error known as wrong blood in tube (WBIT) has been well documented in the hemovigilance system, it has hitherto applied only to one end of the transfusion
Antibodies titration for immunized pregnant women: conventional tube test or gel microcolumn assay Antibody titration and titer monitoring are required throughout pregnancy. Different studies have been published comparing RBC alloantibody titration by gel microcolumn assay (GMA) with conventional tube test (CTT).1-3 Recently Finck and coworkers1 have compared six specificities of alloantibodies identified during routine transfusion. They concluded that GMA was comparable to CTT. In our laboratory, we used gel cards for blood grouping, antibody screening and identification, compatibility testing, and the direct antiglobulin test. Gel tests are easy to use, allow an objective reading of agglutination, and have a stable end point. We titrated 136 antibodies from immunized pregnant women using the two methods: conventional tube and gel card. Titration was performed using serial twofold dilutions in normal saline in test tubes and dilutions were tested in parallel for both tests. Red blood cells (RBCs) were washed three times in normal saline and resuspended to a final concentration of 4% for tube and 0.8% for gel. Briefly, each serum dilution and RBCs were dispensed into each tube or card (Scan gel anti-IgG, Bio-Rad, Marnes La Coquette, France) and incubated. Tubes were incubated at 37°C for 30 minutes and gel cards at 37°C for 15 minutes. After three washings, antiglobulin was added, the tubes were centrifuged, and the agglutination was read. Gel cards do not require washing and addition of antiglobulin sera. The standard anti RH1 (Diagast, Loos, France) with a known titer (512) was tested in each series. Titration is a semiquantitative method and a difference of one titer was accepted.4 The difference in titers between the two methods is shown in Table 1. A total of 136 alloimmunized obstetric patients were included and titrations were performed on 11 specificities. For 53 (39%) antibody titrations, the two methods gave similar results or within one titer; for 31 (23%) titrations, there was a difference of two titers, and for 52 (38%), three or more titers. A total of 188 were performed with the standard anti-RH1 IgG. GMA results were the same as CTT results in 41 (22%) samples and there was a difference of two titers for 122 (65%) samples and three titers or more for 25 (13%) samples. In the study by Finck and colleagues,1 GMA and CTT generated similar results or within one titer for 42 of 48 (85%) patients but the assays were performed with antibodies generated after transfusion and none from obstetric patients. GMA titers in our study tend to be higher than the tube titers. Based on these data, it is currently difficult to accept the GMA to monitor immunized pregnant women. 1200
TRANSFUSION Volume 54, April 2014
TABLE 1. The difference in titers between GMA and CTT Antibody specificity Anti-D Anti-D + anti-C Anti-D + anti-E Anti-C Anti-E Anti-c Anti-Cw Anti-Kell Anti-S Anti-Jka Anti-Fya Total Anti-RH1 IgG
Titers no difference, Number 7 14 7 4 39 32 7 8 12 3 3
Titers major difference,
2
3 or more
0–1 3 0 2 3 21 8 3 4 5 1 3
136 188
Titers minor difference,
53 (39%) 41 (22%)
1 3 0 1 6 10 3 4 1 2 0 31 (23%) 122 (65%)
3 11 5 0 12 14 1 0 2 0 0 52 (38%) 25 (13%)
CONFLICT OF INTEREST The authors report no conflicts of interest or funding sources.
Alexis Duez, MD1 e-mail: [email protected] Françoise Flourié, MD2 Olivier Garraud, MD, PhD3 1 Laboratoire d’Hématologie Hôpital Nord, CHU de Saint Etienne 2 Laboratoire d’Immuno-Hématologie 3 EFS Auvergne – Loire Saint Etienne, France
REFERENCES 1. Finck R, Deguzman-Lui C, Teng S, et al. Comparison of a gel microcolumn assay with the conventional tube test for red blood cell alloantibody titration. Transfusion 2013;53:811-5. 2. Novaretti MC, Jens E, Pagliarini T, et al. Comparison of conventional tube test with Diamed gel microcolumn assay for anti-D titration. Clin Lab Haematol 2003;25:311-5. 3. Thakur MK, Marwaha N, Kumar P, et al. Comparison of gel test and conventional tube test for antibody detection and titration in D-negative women: study from a tertiary-care hospital in North India. Immunohematology 2010;26:174-7. 4. Roback JD, Grossman BJ, Harris T, Hillyer CD. Technical manual. 17th ed. Bethesda (MD): American Association of Blood Banks; 2011.
Wrong blood in tube error: first study on donor blood samples Although the error known as wrong blood in tube (WBIT) has been well documented in the hemovigilance system, it has hitherto applied only to one end of the transfusion
