direct Coombs' test

Coombs' test

any of a number of tests to ascertain the presence or absence of immunoglobulin and complement in the coating of erythrocytes. Rabbit antihuman serum is used to act as a bridge between sensitized cells, yielding agglutination (a positive result). The tests can be used to differentiate between various types of hemolytic anemias, to determine minor blood types including the Rh factor, and to test for anticipated erythroblastosis fetalis.
direct Coombs' test the test used to detect in vivo sensitization of red blood cells and formation of cell-bound antibodies that may damage erythrocytes but will not cause visible agglutination. The erythrocytes are washed free of serum and unbound antibody, and antiglobulin (antiserum directed against human antibodies and complement components) is added. Agglutination indicates the presence of antibody. Clinically its most important use is in early diagnosis of erythroblastosis fetalis and autoimmune hemolytic anemias. It is used also in crossmatching blood for transfusions. Venous blood or blood from the umbilical cord may be used.
indirect Coombs' test a test for detecting antigen-antibody reactions that occur in vitro; used to determine incompatibility in transfusions when the recipient has a greater than normal risk of transfusion reaction. It uses antiglobulin serum to detect the in vitro sensitization of red blood cells by serum. The test also can reveal the presence of anti-Rh antibodies in maternal blood during pregnancy. Either clotted blood or blood with an anticoagulant may be used. The patient's serum is incubated with donor red blood cells, the cells are washed, and antiglobulin added. Agglutination indicates the presence of incomplete sensitizing antibodies in the serum.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
References in periodicals archive ?
Initial lab results were remarkable for ANC <100, ferritin of 1237 ng/mL, positive direct Coombs' test, weakly positive anti-dsDNA, mildly elevated RF, and low C3/C4.
Direct Coombs' test, and cold agglutinin, serum immunoglobulins, antinuclear antibody, total protein, and lipid levels were normal.
The DAT test (also known as a direct Coombs' test) has been used since the 1950s to see whether the donor has immunoglobulin antibodies attached to red blood cells, according to Dr.
Hb of 4.1 g/dl with 4+ direct Coombs' test. It was learned that methylprednisolone 10 mg/kg/day had been initiated and the dose was tapered off subsequently; however, he had two more attacks during periods of dose reduction of steroid treatment and needed doses as high as 20 mg/kg/day for hemolysis control.
Direct Coombs' test and an antinuclear antibody test were negative, and the levels of serum immunoglobulins G, M, and A as well as complements 3 and 4 were within the reference range.
Clinico-hematological characteristics of the three cases of primary autoimmune myelofibrosis in this report Case Age/ Associate Spleen Hb g/L TLC No Sex d Disease (below LCM) x [10.sup.9]/L 1 38/M None 4 cm 52 3.20 2 29/M None 4 cm 68 7.3 3 33/M None 3 cm 59 2.9 Case Age/ Platelet Serology Response to Bone No Sex Count x Steroids Marrow [10.sup.9]/L Histology 1 38/M 126 ANA+, PR Reticulin Anti ds Grade 2 DNA+ 2 29/M 162 ANA-, PR Reticulin Anti ds Grade 2 DNA-, RF- 3 33/M 95 DCT+ PR Reticulin ANA-, Grade 3 DNA- LCM: Lower left costal margin; ANA: Antinuclear antibody; RF: Rheumatoid factor; PR: Partial remission (normal blood counts, still palpable spleen); DCT: Direct Coombs' test; -: Negative; +: Positive Table 2.