Haemolytic Screen
Haemolytic Screen
 

Direct Antiglobulin Test

 
 
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Overview

  • The direct antiglobulin test (DAT), also known as the direct Coomb's, tests for IgG and complement 3 (C3) on the surface of red blood cells. The test is performed by adding antibodies against human IgG or C3 and monitoring for agglutination.
  • A positive test indicates an immune (autoimmune, alloimmune or drug-induced) cause of haemolysis, and may be positive before haemolysis occurs.
    • Causes of Positive Direct Antiglobulin Test

    • Normal in certain patients
    • False positive - clotted sample, poor testing technique, elevated serum immunoglobulins
    • Warm autoimmune haemolytic anaemia - idiopathic, lymphoproliferative disorders, infection, autoimmune disorders, methyldopa, penicillins, cephalosporins, rifampicin, quinine, paracetamol, ibuprofen
    • Cold agglutinin haemolysis - idiopathic, mycoplasma pneumoniae, EBV, lymphoma, paroxysmal cold haemoglobinuria
    • Alloimmune haemolysis - transfusion of mismatched red blood cells, haemolytic disease of the newborn, post stem cell transplant
    • Drug-induced haemolysis
Last updated on March 3rd, 2020
 
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 Bain BJ. Diagnosis from the blood smear. New England Journal of Medicine. 2005 Aug 4;353(5):498-507. Barcellini W, Fattizzo B. Clinical applications of hemolytic markers in the differential diagnosis and management of hemolytic anemia. Disease markers. 2015 Dec 27;2015. Choi JW, Pai SH. Change in erythropoiesis with gestational age during pregnancy. Annals of hematology. 2001 Feb 16;80(1):26-31. Drent M, Cobben NA, Henderson RF, Wouters EF, van Dieijen-Visser M. Usefulness of lactate dehydrogenase and its isoenzymes as indicators of lung damage or inflammation. European Respiratory Journal. 1996 Aug 1;9(8):1736-42. Gorst DW, Rawlinson VI, Merry AH, Stratton F. Positive direct antiglobulin test in normal individuals. Vox sanguinis. 1980 Feb 1;38(2):99-105. Lurie S, Mamet Y. Red blood cell survival and kinetics during pregnancy. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2000 Dec 31;93(2):185-92. Maekawa M. Lactate dehydrogenase isoenzymes. Journal of Chromatography B: Biomedical Sciences and Applications. 1988 Jul 29;429:373-98. Marchand A, Galen RS, Van Lente F. The predictive value of serum haptoglobin in hemolytic disease. Jama. 1980 May 16;243(19):1909-11. Papadopoulos NM. Clinical applications of lactate dehydrogenase isoenzymes. Annals of Clinical & Laboratory Science. 1977 Nov 1;7(6):506-10. Parker V, Tormey CA. The Direct Antiglobulin Test: Indications, Interpretation, and Pitfalls. Archives of Pathology & Laboratory Medicine. 2017 Feb;141(2):305-10. Shih AW, McFarlane A, Verhovsek M. Haptoglobin testing in hemolysis: measurement and interpretation. American journal of hematology. 2014 Apr 1;89(4):443-7.
Tabbara IA. Hemolytic anemias: diagnosis and management. Medical Clinics of North America. 1992 May 1;76(3):649-68.
 Ucar K. Clinical presentation and management of hemolytic anemias. Oncology. 2002 Sep 16;16(9; SUPP/10):163-70. Zantek ND, Koepsell SA, Tharp DR, Cohn CS. The direct antiglobulin test: a critical step in the evaluation of hemolysis. American journal of hematology. 2012 Jul 1;87(7):707-9.
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