ABSTRACT
Background A variation in the measurement of ABO antibody titer has been seen among different laboratories due to lack of standardization. In our study, we aim to evaluate automated ABO isoagglutinin titer measurements by erythrocytes magnetized technology (EMT) and compare with conventional tube technique (TT). Methods We performed ABO isoagglutinin titration on samples received in a reference laboratory during a period of 2 months. A total of 134 tests for immunoglobulin G (IgG) titer and 116 for immunoglobulin M (IgM) for anti-A or anti-B were included in the study. Samples were processed for ABO isoagglutination titers by both TT and EMT by QWALYS-3 (DIAGAST, France). Microsoft Excel was used to compile data, for all calculations, and to draw graphs and plots. The number and percentage of cases within ±1, ±2, or ±3 titer difference (TT-EMT) were calculated. Results Median titers and their ranges obtained by EMT were higher or equal to those by TT for all IgM and IgG ABO-antibodies in all blood group (BGs), except anti-A IgM in (BG) O that was lower by EMT (32 [4:128]) than TT (48 [8:256]). One twenty one (121/134, 90.3%) cases of IgG titer showed an agreement by both methods (within ± one titer difference). One hundred seven cases (107/116, 92.2%) for IgM titer were within one titer difference by both the methods. Conclusion Results of titration by EMT-based automated instrument QWALYS-3 and conventional TT may vary by one titer dilution in the majority of cases. Use of consistent method for patient management is, therefore, advised.
ABSTRACT
Hemoglobin High-performance liquid chromatography (Hb HPLC) is a standard first-line technique for diagnosis of thalassemia and hemoglobinopathies. We compared two HPLC systems for detection and quantification of normal and abnormal Hb fractions. EDTA samples from 100 normal healthy subjects and 107 subjects affected with hemoglobinopathies or carriers were analysed using HPLC systems Tosoh HLC-723G11 and Bio-Rad Variant-II. Retention time (RT) and area of peaks for HbA2, HbF and other structural variants were compared. In discrepant cases samples were run on Sebia Capillary zone electrophoresis (CZE) for confirmation of results (39 out of 107 cases with HbE, HbD Iran, Hb Lepore and HbQ). Measurement of HbA2 and HbF in normal samples and HbF in those with variant Hbs showed good correlation by both analyzers (R 2 = 0.83, 0.9 and 0.99 respectively). HbE co-elutes with HbA2 in Bio-Rad. Correlation done using the apparent HbA2 concentration from Bio-Rad with (HbE + HbA2) from Tosoh G11 showed good correlation (R 2 = 0.97). Correlation of HbS (Eluting at S-window at RT 3.11 min in Tosoh G11 and 4.33 min in Bio-Rad) as well as HbD Punjab (Eluting at D-window at RT 2.82 min in Tosoh G11 and 4.06 min in Bio-Rad) by both instruments was good. HbD Iran (Eluting at E-window at RT 2.69 min in Tosoh G11 and with HbA2 at 3.53 min in Bio-Rad); HbQ (Eluting at C-window at RT 3.78 min in Tosoh G11 and unknown window at 4.7 min in Bio-Rad), HbH (Eluting at P00 window at RT 0.13 min in Tosoh G11 and giving pre-integration peak in Bio-Rad), Hb Lepore (Eluting at P08 window at RT 2.67 min in Tosoh G11 and with HbA2 at 3.46 min in Bio-Rad) gave comparable results. Correlation with findings of CZE was done in few cases when needed. Two automated HPLC instruments demonstrated similar usefulness for screening patients for hemoglobinopathies. However, complex elution patterns as well as co-elution of variants like HbA2, HbE, Hb Lepore, HbD Iran (in Bio-Rad); HbD Iran and HbE (Tosoh G11) pose difficulty in interpretation. A complementary second method like CZE may be required.
