Query: direct coombs tests in HDN

title: Readmission for Newborn Jaundice: The Value of the Coombs' Test in Predicting the Need for Phototherapy
abstract: Current practice at our hospital is to perform a direct antiglobulin test (DAT) on cord blood samples of all infants born to blood type O or Rh negative mothers. Measurement of serum total bilirubin (STB) level and follow up after discharge are at the discretion of the individual physician. The purposes of the present study were, first, to determine the clinical utility of performing a routine DAT and, second, to define the clinical characteristics of infants readmitted to the hospital for phototherapy. The study was done over a 1 year period extending from January 1 to December 31, 2000. A retrospective review of the DAT results of all infants born to type O or Rh negative mothers was conducted. The 2 groups of infants included those who had a positive cord blood DAT and were treated with phototherapy and those who needed readmission to the hospital for phototherapy. We found that routine DAT testing of cord blood from term nonjaundiced infants born to O positive mothers is not necessary. Infants with 2 or more risk factors for jaundice irrespective of the results of the DAT are at an increased risk for needing readmission for phototherapy.

title: Wasted health care dollars. Routine cord blood type and Coombs' testing.
abstract: To determine if selective newborn cord blood testing (NCBT) could contain costs without increasing morbidity of hemolytic disease of the newborn (HDN) DESIGN A national telephone survey confirmed the common practice of routine blood type and Coombs' NCBT. Two 12 month study arms, retrospective and prospective, were conducted. Hemolytic disease of the newborn was studied retrospectively under an unrestricted NCBT policy. Then, HDN was studied after a policy change that restricted NCBT to patients in newborn intensive care units and normal newborns with clinical jaundice or Rh negative mothers, and/or positive maternal antibody screenings, or unavailable maternal blood testing.  All newborns (N 8501) at the Metro Health Medical Center, Cleveland, Ohio, were studied (retrospective arm, all 1989 admissions; prospective arm, all July 1990 to June 1991 admissions) OUTCOME MEASURES Blood type and Coombs' NCBT, maternal blood type and antibody screening, Hobel risk scores for clinical severity of newborn hospitalization, duration of hospitalizations, and peak serum bilirubin levels.  No quantitative or qualitative increases in morbidity from jaundice were detected by retrospective analysis with unrestricted NCBT, or prospectively after selective testing on 4498 newborns. Each study arm resulted in 15 readmissions for jaundice; these included two patients with ABO HDN. Furthermore, selective testing resulted in performance of NCBTs on only 390 infants in the "normal" nursery (24% of the original sample) Estimates projected on 1991 US births (4,111,000) showed that selective NCBT offers potential yearly savings above $30.8 million of patient charges, savings above $11.3 million of hospital costs, and the reassignment of more than 112 personnel full time equivalents.  Selective NCBT decreases the use of resources and costs without apparent additional patient morbidity from HDN.

title: Evaluation of the Direct Antiglobulin (Coombs' Test for Identifying Newborns at Risk for Hemolysis as Determined by End Tidal Carbon Monoxide Concentration (ETCOc) and Comparison of the Coombs' Test With ETCOc for Detecting Significant Jaundice
abstract: First, to determine the sensitivity, specificity, and positive predictive value (PPV) of the direct antiglobulin test (DAT) for significant hemolysis in the neonate, as referenced to end tidal carbon monoxide, the criterion standard for estimating the rate of hemolysis; and second, to evaluate the predictive value of the two procedures for significant jaundice. Consecutive term newborns admitted to the nursery of an inner city university hospital over a 15 week period. DAT screening by the Blood Bank was performed on all. End tidal carbon monoxide levels were obtained at 12+ 6 and at 24+ 6 hours of age. Infants of nonsmoking mothers whose 12 hour exhaled carbon monoxide level was =95th percentile were defined as having significant hemolysis. n=660; DAT was positive in 23 (3.5% Using the 12 hour end tidal carbon monoxide =3.2 ml/l =95th percentile) as reference (n=499 nonsmokers) the sensitivity of the DAT was 38.5% (10 of 26) and specificity 98.5% (466 of 473) for the detection of significant hemolysis. The PPV of the DAT for significant hemolysis at 12 hours was 58.8% (10 of 17) For significant jaundice the PPV of end tidal carbon monoxide was greater than that for DAT (65.4% vs 52.9% although not statistically so (p=0.25) The negative predictive values were similar. DAT fails to identify over half of the cases of significant hemolysis that are diagnosed by end tidal carbon monoxide. A neonate with a positive DAT has about a 59% chance of having significant hemolysis. End tidal carbon monoxide may also provide a more sensitive index for predicting significant jaundice.

title: Rediscovering the Coombs test
abstract: The antiglobulin, or Coombs test is part of the compatibility tests that any patient who will receive a red blood cell transfusion must undergo. This test is also essential in the diagnostic work of patients with anemia whose origin is not easily determined and when the etiology must be identified precisely. In 1945, Robin Coombs, Arthur Mourant and Rob Race described a test to detect anti Rho (anti D) non agglutinant antibodies. Originally, the test was devised by Robin Coombs as part of his postgraduate studies at Race and Mourant's laboratory in Cambridge, England in 1945. His goal was to study the characteristics of the antibodies involved in the context of what was known as fetal erythroblastosis, which is now known as hemolytic disease of the newborn (HDN) caused most frequently by the incompatibility between an Rh negative mother sensitized during a previous pregnancy, who produces IgG anti D antibodies able to pass the placenta barrier due to their small size that then cover the fetal red blood cells. These are later phagocytosed in the spleen and liver, organs which, in addition to their other functions, maintain extramedullary hematopoiesis in the fetus to compensate for anemia resulting from hemolysis. Later, the Coombs test was used to demonstrate the presence of incomplete antibodies which covered the erythrocytes in vivo, such as is seen in cases of autoimmune hemolytic anemia (AHA) The description of the method,

title: Outcome and cost analysis of implementing selective Coombs testing in the newborn nursery
abstract: Objective:(1) To determine whether infants born to O+ mothers who had selective cord blood testing would have higher rates of clinically significant hyperbilirubinemia compared with those newborns who had routine cord blood testing. (2) To determine the amount of cost savings by implementing a policy of selective cord blood testing in newborns born to O+ mothers.We conducted a retrospective pre/post intervention chart review on all infants in the normal newborn nursery at Loyola, born to blood type O+ women between 1 April 2008 and 1 April 2009. The pre intervention group (routine testing) included infants born within 6 months before implementation of a new policy. The post intervention group (selective testing) included infants born within 6 months following the implementation of a new policy. Data were collected for each of these groups regarding clinically significant hyperbilirubinemia.All 250 of the infants in the routine testing group had a cord blood type and Coombs done, whereas 42 of 164 (25% infants in the selective group had testing done. By the end of the 6 months following the policy change, only 8% of infants were undergoing cord testing. When comparing routine vs selective testing, there was no statistically significant difference in the 24 h serum bilirubin, rate of phototherapy during the birth hospitalization, rate of readmission for hyperbilirubinemia or peak serum bilirubin level at readmission. The 92% reduction of cord blood typing and Coombs testing would lead to a cost saving of $4100 per year to our hospital and $18 900 per year to our patients, and 95 h per year of technician time to perform these tests. When extrapolated to Illinois births in 2008, this would lead to an annual cost saving of almost $800 000 to Illinois hospitals and about $3.6 million to patients.Selective newborn cord testing of infants born to O+ mothers can decrease the use of resources and costs without increasing the risk of clinically significant hyperbilirubinemia.

title: Utilidad de la prueba directa de Coombs en el tamiz neonatal
abstract: Neonatal jaundice is a clinical event frequently present in newborns. The causes most frequently involved in hemolytic disease of newborn (HDN) are still the incompatibilities to the ABO/Rh blood system. Direct Coombs test (or direct antiglobulin test, DAT) allows identification of the presence of red blood cell antibodies (IgG isotype) coming from the maternal serum on the surface of the fetus erythrocytes. The purpose of this study is to show the results and specificity of DAT as screening in newborn infants.  We studied unselected neonates in a cross sectional design. During the early hours of life, we determined ABO/Rh and DAT with poly and monospecific reagents (anti IgG and C3b/C3d) Results. We included 5 007 newborns; 181 cases (3.6% were DAT positive. Newborns with A, B or AB blood groups showed an increased association of being DAT positive than group O (OR 2.3, 95% CI 1.7 3.1) DAT was positive in 3.5% of RhD positive infants and 1.9% of RhD negative infants. In six DAT positive cases, 117 cases (64.6% had anti IgG bound to red cell membrane, complement in six cases (3.3% and 52 newborns (28.8% were polyspecific DAT positive and monospecific DAT negative.  The high prevalence (3.6% of DAT positive cases in routine neonatal detection supports the indication to incorporate DAT into neonatal screening, regardless of the mother's blood group. The benefit of early intervention in neonatal jaundice remains to be established.

title: How to use: the direct antiglobulin test in newborns
abstract: The direct antiglobulin test (DAT) detects the presence of immunoglobulin, complement or both bound to the red blood cell membrane. The test, historically called the 'Coombs test' was first described in 1945 by Cambridge immunologist Robin Coombs. Suspected haemolytic disease of the newborn, due to either Rhesus disease or ABO incompatibility, is one of most common reasons for requesting a DAT in newborns. In this article, we discuss the physiological background and technological background of the DAT. We also provide a clinical framework for a rational approach to the use and interpretation of the DAT in newborns.

title: Historical Note: Past, Present and Future of the Antiglobulin Test
abstract: This is a review of two invited talks on the antiglobulin reaction on the occasion of the 50th Anniversaries of the International Blood Group Reference Laboratory, now at Bristol, and the National Blood Service, London, and coincidentally the 51st anniversary of the antiglobulin test! The first talk (as specially requested) is a very personal reminiscence of the discovery, with Rob Race and Arthur Mourant, of the antiglobulin test in blood group serology. The second talk traces developments in antiglobulin testing in general immunology using, of course, isotype specific antiglobulin reagents as and when they became available. Special emphasis was given to: (1) testing for poorly agglutinating bacterial antibodies; (2) special procedures for measuring reaginic (IgE) antibodies to various allergens; (3) the incorporation of an antiglobulin step or stage in many of the routine automated immunoassay procedures; (4) the special experimental procedures in the form of mixed antiglobulin reactions to reveal antibodies to the surface antigens on tissue cells, and, finally, (5) by chemically coupling antiglobulin to red blood cells, a distinctive integrated immunoassay system was developed, enabling reverse passive haemagglutination as an assay for immunoglobulins, rosetting reactions to reveal native IgG receptors on lymphocytes or antibody immunoglobulin reacting with CD marker antigens; this same reagent, namely red cell labelled antiglobulin, can be used to detect antibodies reacting with either bacteria or antigens adsorbed on the walls of wells of microtitre plates. The need for improved stabilization and preservation of the antiglobulin linked red cells to prolong their 'shelf life' is stressed.

title: Efficacy of Whole Blood Reconstituted (WBR) in Exchange Transfusion (ET) in Hemolytic Disease of New Born (HDN) A Study of 110 Cases
abstract: This study was aimed to review and establish the practice of exchange transfusion (ET) with whole blood reconstituted (WBR) in hemolytic disease of newborn (HDN)  To observe fall in indirect serum bilirubin, correction of anemia and comparison with related studies.  Hemolytic disease of the Newborn is characterized by presence of IgG antibodies in maternal circulation, which causes hemolysis in the fetus by crossing the placenta and sensitizing red cells for destruction by macrophages in the fetal spleen with consequent hyperbilirubinemia. Exchange transfusion with or without phototherapy is the method of choice for treating the newborn with on going hemolysis  Sample size consisted of 110 neonates in whom 119 exchange transfusions were carried out with WBR. WBR was prepared by suspending O Rhesus D (RhD) positive/negative cells (compatible with neonate's/ mother's serum) in AB plasma. Double volume exchange transfusion(s) were carried out through umbilical vein by push pull technique.  Out of 110 cases, 61 (55.5% were of RhD HDN whereas ABO and other group HDN cases were 30 (27.3% and 19 (17.3% respectively. An average post ET fall in indirect serum bilirubin by 54.6% and correction of anemia by3.7 gm/dl were reported in the study.  An average post ET fall in indirect serum bilirubin and correction of anemia was found to be more significant when compared to other studies. Hence we recommend exchange transfusion in HDN with WBR to obtain reasonable fall in indirect serum bilirubin and high average rate of correction of anemia.

title: A comparison of conventional tube test and gel technique in evaluation of direct antiglobulin test
abstract: In vivo coating of red cells by antibody and/or complement is detected using various sensitive techniques, however most hospitals even today rely on the conventional tube technique (CTT) We compared the performance of the CTT and recently introduced gel test (GT) in the evaluation of direct antiglobulin test (DAT) The CTT and GT were first compared using in house prepared control cells. The polyspecific DATs were performed simultaneously by CTT and GT on 170 consecutive blood samples. Positive samples were further tested for monospecific IgG and C3d by both techniques. GT demonstrated stronger agglutination scores (60 vs. 43) compared to CTT using control cells. The sensitivity and specificity of the GT was 98.4 and 95.2% respectively as compared to CTT for polyspecific DAT. Discordance between the two test systems was seen in 6/170 patients. Of these, 5 were missed by CTT while GT failed to detect in vivo coating in only 1 case. The agreement between two methods of DAT was 96.4% (k 0.926) using polyspecific AHG and 95.7% (k 0.379) with mono specific anti IgG. We conclude that GT is a better alternative to CTT for detecting red cell bound antibodies in various clinical conditions.