-
Archives of Pathology & Laboratory... Feb 2017The direct antiglobulin test (DAT; sometimes referred to as the "Coombs" test) continues to be one of the most widely used assays in laboratory medicine. First described... (Review)
Review
The direct antiglobulin test (DAT; sometimes referred to as the "Coombs" test) continues to be one of the most widely used assays in laboratory medicine. First described about 70 years ago, it is elegantly simple in design, yet it is widely complex in its applications and interpretations, and it is prone to false-positive and false-negative results. The overall objective of our review is to provide practicing pathologists with a guide to identify situations when the DAT is useful and to highlight disease-specific shortcomings as well as general pitfalls of the test. To accomplish these goals, this review will discuss the following: (1) the history of the DAT, (2) how the test is performed in the clinical laboratory, (3) clinical situations for its use, (4) its interpretation, and (5) the pitfalls associated with DAT assays, including causes of false positivity.
Topics: Coombs Test; Humans
PubMed: 28134589
DOI: 10.5858/arpa.2015-0444-RS -
American Journal of Hematology Jul 2012The direct antiglobulin test (DAT) is a laboratory test that detects immunoglobulin and/or complement on the surface of red blood cells. The utility of the DAT is to... (Review)
Review
The direct antiglobulin test (DAT) is a laboratory test that detects immunoglobulin and/or complement on the surface of red blood cells. The utility of the DAT is to sort hemolysis into an immune or nonimmune etiology. As with all tests, DAT results must be viewed in light of clinical and other laboratory data. This review highlights the most common clinical situations where the DAT can help classify causes of hemolysis, including autoimmune hemolytic anemia, transfusion-related hemolysis, hemolytic disease of the fetus/newborn, drug-induced hemolytic anemia, passenger lymphocyte syndrome, and DAT-negative hemolytic anemia. In addition, the pitfalls and limitations of the test are addressed. False reactions may occur with improper technique, including improper washing, centrifugation, and specimen agitation at the time of result interpretation. Patient factors, such as spontaneous red blood cell agglutination, may also contribute to false results.
Topics: Adult; Anemia, Hemolytic; Anemia, Hemolytic, Autoimmune; Anemia, Hemolytic, Congenital; Blood Group Incompatibility; Coombs Test; Hemolysis; Humans; Infant, Newborn
PubMed: 22566278
DOI: 10.1002/ajh.23218 -
Blood Advances Jun 2019The terminology applied to autoimmune hemolytic anemia (AIHA) seems inconsistent. We aimed to evaluate the consistency of definitions used for diagnosis and treatment.... (Comparative Study)
Comparative Study
The terminology applied to autoimmune hemolytic anemia (AIHA) seems inconsistent. We aimed to evaluate the consistency of definitions used for diagnosis and treatment. In this systematic review of literature from January 2006 to December 2015, we assessed heterogeneity in the definition of AIHA and its subtypes, refractory disease, disease phase, severity, criteria for treatment response, and response durability. A Medline search for anemia, hemolytic, autoimmune was supplemented with keyword searches. Main exclusions were conference abstracts, animal and non-English studies, and studies with <10 cases. Of 1371 articles retrieved, 1209 were excluded based on titles and abstracts. Two authors independently reviewed 10% and 16% of abstracts and full papers, respectively. After full-paper review, 84 studies were included. AIHA was most frequently (32 [52%] of 61) defined as hemolytic anemia with positive direct antiglobulin test (DAT) and exclusion of alternatives, but 10 of 32 also recognized DAT-negative AIHA. A lower threshold for diagnosis of DAT-negative AIHA was observed in literature on chronic lymphocytic leukemia. Definitions of anemia, hemolysis, and exclusion criteria showed substantial variation. Definitions of primary/secondary cold agglutinin disease/syndrome were not consistent. Forty-three studies provided criteria for treatment response, and other than studies from 1 center, these were almost entirely unique. Other criteria were rarely defined. Only 7, 0, 3, 2, 2, and 3 studies offered definitions of warm AIHA, paroxysmal cold hemoglobinuria, mixed AIHA, AIHA severity, disease phase, and refractory AIHA, respectively. Marked heterogeneity in the time period sampled indicates the need to standardize AIHA terminology.
Topics: Anemia, Hemolytic, Autoimmune; Coombs Test; Erythrocytes; Hemoglobinuria, Paroxysmal; Hemolysis; Humans; Immunoglobulin G; Publications; Severity of Illness Index; Terminology as Topic
PubMed: 31235526
DOI: 10.1182/bloodadvances.2019000036 -
Blood Aug 2020
Topics: Betacoronavirus; COVID-19; Coombs Test; Coronavirus Infections; Erythrocytes; Humans; Immunoglobulin G; Pandemics; Pneumonia, Viral; SARS-CoV-2
PubMed: 32761221
DOI: 10.1182/blood.2020007483 -
Tuberkuloz Ve Toraks Mar 2020Brucellosis is widely distributed zoonotic infection. Brucellosis is a multisystemic disease but pulmonary infection due to brucellosis is very rarely reported. (Review)
Review
INTRODUCTION
Brucellosis is widely distributed zoonotic infection. Brucellosis is a multisystemic disease but pulmonary infection due to brucellosis is very rarely reported.
MATERIALS AND METHODS
We retrospectively evaluated our pediatric brucellosis cases between February 2014 and December 2015. The brucellosis patients with and without pulmonary infection were compared with each other.
RESULT
We detected pulmonary infection in 18 of the 98 brucellosis patients. There was no statistical significant difference between the brucellosis patients with and without a pulmonary infection as regards age, gender, and animal husbandry history. The laboratory findings including the Brucella Coombs agglutination titers were also similar. The most common chest X-ray findings were interstitial infiltration and hilar lymphadenopathy. All of our cases with pulmonary infection recovered with the usual anti-brucella treatment.
CONCLUSIONS
Brucellosis may cause a pulmonary infection more often than thought. The prognosis of respiratory brucellosis is good and the classic treatment regimen is appropriate.
Topics: Animals; Brucella; Brucellosis; Child; Coombs Test; Female; Humans; Lung Diseases, Interstitial; Male; Respiratory Tract Infections; Retrospective Studies
PubMed: 32718139
DOI: 10.5578/tt.69015 -
Immunobiology Jul 2022Previous case reports have described patients with COVID-19-associated autoimmune hemolytic anemia (AIHA), and cold agglutinin disease (CAD) which is characterized by a...
Previous case reports have described patients with COVID-19-associated autoimmune hemolytic anemia (AIHA), and cold agglutinin disease (CAD) which is characterized by a positive direct antiglobulin (DAT) or "Coombs" test, yet the mechanism is not well understood. To investigate the significance of Coombs test reactivity among COVID-19 patients, we conducted a retrospective study on hospitalized COVID-19 patients treated at NMC Royal Hospital between 15 April and 30 May 2020. There were 27 (20%) patients in the Coombs-positive group and 108 (80%) in the Coombs-negative group. The cold agglutinin titer was examined in 22 patients due to symptoms suggestive of cold agglutinin disease, and all tested negative. We demonstrated a significant association with reactive Coombs test results in univariate analysis through clinical findings such as ICU admission rate, the severity of COVID-19, and several laboratory findings such as CRP, D-dimer, and hemoglobin levels lactate dehydrogenase, and RDW-CV. However, only hemoglobin levels and disease severity had a statistically significant association in multivariate analysis. A possible explanation of COVID-19-associated positive Coombs is cytokine storm-induced hyperinflammation, complement system activation, alterations of RBCs, binding of SARS-CoV-2 proteins to hemoglobin or its metabolites, and autoantibody production. Coombs-positive patients were tested for hemolysis using indirect bilirubin, consumed haptoglobin, and/or peripheral smear that ruled out any evidence of hemolysis. Understanding this etiology sheds new light on RBC involvement as a pathophysiological target for SARS-CoV-2 by interfering with their function; consequently, therapies capable of restoring RBC function, such as erythrocytapheresis, could be repurposed for the treatment of worsening severe and critical COVID-19.
Topics: Anemia, Hemolytic, Autoimmune; Antibodies, Anti-Idiotypic; COVID-19; Coombs Test; Hemoglobins; Hemolysis; Humans; Retrospective Studies; SARS-CoV-2
PubMed: 35839729
DOI: 10.1016/j.imbio.2022.152240 -
British Medical Journal Jul 1968The case histories of two patients with penicillin-induced haemolytic anaemia are presented. One had received 20 mega units a day for 18 days, the other had received 20...
The case histories of two patients with penicillin-induced haemolytic anaemia are presented. One had received 20 mega units a day for 18 days, the other had received 20 mega units a day for two days and then 12 mega units a day for 25 days, before the haemolytic anaemia was diagnosed. Both had previously had courses of penicillin. A strongly positive direct antiglobulin reaction which appeared to be mainly due to IgG antibody was one of the main diagnostic features, and free IgG antipenicillin antibody was found in the serum of both patients. The haemolysis appeared to Lessen as soon as the drug was stopped, and the direct antiglobulin test became negative in 66-77 days.Twelve additional reported cases are reviewed. All had received high doses of penicillin and all had had penicillin previously. The lowest dose recorded was 10 mega units a day for 26 days. The incidence of anti-penicillin antibodies in a hospital population is given, and the mechanism of this type of haemolytic anaemia is discussed. Penicillin-induced haemolytic anaemia should be suspected in any patient receiving penicillin in high doses in whom there is a fall in the haemoglobin level.
Topics: Aged; Anemia, Hemolytic; Antibodies; Coombs Test; Erythrocytes; Female; Haptens; Hemagglutination Tests; Humans; Immunoglobulin G; Male; Middle Aged; Penicillins
PubMed: 5661907
DOI: 10.1136/bmj.3.5609.26 -
The Journal of International Medical... Mar 2020The indirect antiglobulin test (IAT) and direct antiglobulin test (DAT) have been used as common tests for transfusion. Recently, we have found that in addition to...
BACKGROUND
The indirect antiglobulin test (IAT) and direct antiglobulin test (DAT) have been used as common tests for transfusion. Recently, we have found that in addition to causing false increases, rheumatoid factor (RF) can also cause false decreases in immunoassays for hepatitis B surface antigen and B-type natriuretic peptide. However, it remains unclear whether RF also interferes with the IAT and DAT.
METHODS
IAT models were produced by mixing IAT-positive plasma and RF-positive plasma, then one-step and two-step IATs were adopted for detection. DAT models were produced by mixing DAT-positive red blood cells (RBCs) and RF-positive plasma, followed by detection with the DAT. The DAT models were diluted using the same RF-positive plasma, and the DAT was performed again.
RESULTS
The rate of decrease of the two-step IAT (40.63%) was significantly higher than that of the one-step IAT (31.51%). Both the rate of decrease (76.67%) and increase (16.67%) of the results of the 60 DAT models were significantly higher than those of the IAT models after two-fold dilution.
CONCLUSIONS
The RF can lead to both false decreases and false increases in IAT and DAT. And the interference effects are related to the RF content relative to the IgG-sensitized RBCs.
Topics: Blood Transfusion; Coombs Test; Erythrocytes; Rheumatoid Factor
PubMed: 31854210
DOI: 10.1177/0300060519892386 -
Acta Haematologica 2018
Topics: Algorithms; Anemia, Hemolytic, Autoimmune; Coombs Test; Humans
PubMed: 30007988
DOI: 10.1159/000489253 -
Annals of the New York Academy of... Jun 1965
Topics: Autoantibodies; Autoimmune Diseases; Basement Membrane; Coombs Test; Humans; Hyperplasia; Myxedema; Necrosis; Radionuclide Imaging; Thyroglobulin; Thyroid Function Tests; Thyroid Neoplasms; Thyroiditis, Autoimmune; Thyrotropin
PubMed: 4158447
DOI: 10.1111/j.1749-6632.1965.tb18989.x