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Quantitation of IgG on Erythrocytes: Correlation of Number of IgG Molecules per Cell with the Strength of the Direct and Indirect Antiglobulin Tests
Author(s) -
Merry A.H.,
Thomson Eileen E.,
Rawlinson Violet I.,
Stratton F.
Publication year - 1984
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1111/j.1423-0410.1984.tb01564.x
Subject(s) - immunology , antibody , medicine
. The number of IgG molecules bound to the erythrocyte surface for a given agglutination score in the antiglobulin test was studied with several different examples of anti‐D, anti‐E, anti‐c, anti‐Kell, anti‐Fy a , anti‐Jk a and immune anti‐A antisera. The serological scores show a significant correlation with the mean values for bound IgG molecules within a restricted range, although the number bound for a given score may vary by up to 20%. The limit of detection was 100–120 IgG molecules per cell and when over 1,000 were bound, the cells were completely agglutinated. Anti‐Kell bound under low ionic strength saline conditions required a greater number of molecules for a given agglutination strength. The relatively low levels of bound IgG necessary to give strong agglutination make the direct antiglobulin test (DAT) less valuable for following the progress of auto‐immune haemolytic anaemia (AIHA) than a quantitative test. The latter test does not, however, provide any additional information in AIHA cases with a negative DAT as in these the anaemia does not appear to be due simply to the number of bound IgG molecules. Detection of certain antibodies may not be achieved simply by increasing the sensitivity of the antiglobulin test when correctly performed.