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Role of gel test and flow cytometry in diagnosis of Coombs’ negative autoimmune haemolytic anaemia
Author(s) -
FAYEK M. H.,
SAAD A.A.,
EISSA D. G.,
TAWFIK L. M.,
KAMAL G.
Publication year - 2012
Publication title -
international journal of laboratory hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.705
H-Index - 55
eISSN - 1751-553X
pISSN - 1751-5521
DOI - 10.1111/j.1751-553x.2011.01397.x
Subject(s) - coombs test , flow cytometry , receiver operating characteristic , medicine , antibody , gastroenterology , immunology , autoimmune hemolytic anemia
Summary Introduction: This study evaluated the use of both gel test (GT) and flow cytometry (FC) techniques in the detection of red blood cell‐bound immunoglobulin G (IgG) and, hence, the diagnosis of autoimmune haemolytic anaemia (AIHA) in cases that were negative by the conventional tube technique (CTT) direct antiglobulin test (DAT). Methods: The study enrolled 50 clinically diagnosed AIHA patients with CTT Coombs’ negative test and 55 control subjects. GT and FC were performed on both groups. Results: Ninety‐two percent (46/50) of patients were positive by GT. As for FC assay, the Receiver Operating Characteristic curve determined that a cut‐off of 17.5% fluorescence was the best value for interpreting FC‐DAT positively in the group of patients with haemolytic anaemia (100% sensitivity and specificity), while the best cut‐off for mean fluorescence intensity (MFI) was 1.74, with 76% specificity and 96% sensitivity. Both mean percent fluorescence and MFI were significantly higher among patients when compared to controls ( P < 0.001). FC assay results showed no statistically significant correlations with patients’ laboratory data or GT grades ( P > 0.05). Conclusion: Flow cytometry is more sensitive than GT for assessing CTT‐DAT‐negative AIHA. We propose that FC percent fluorescence cut‐off values should be employed to determine the Coombs’ negative AIHA cases.