凝胶微柱法与试管法检测放散液中抗体的比较

目的比较凝胶微柱法和试管法检测红细胞释放液抗体的能力。方法将30例外周血和41例脐血红细胞用两种方法测定直接抗人球蛋白试验(DAT)并进行酸放散,将放散液与三种谱细胞、A1、B细胞反应检测抗体的特异性。71例中12例作为阴性对照样本(DAT均为阴性),其中6例为健康献血者外周血,6例为不发生新生儿溶血病(Heamolytic disease of thenewborn,HDN)的婴儿脐血样本。结果24例外周血放散液中有10例两种方法均阳性,12例均为阴性,2例自身免疫性溶血性贫血(AIHA)患者样本凝胶微柱法阳性而试管凝集法阴性,6例健康捐献者的样本DAT试验阴性且两种方法检测放散液均为阴性;41例脐血样本中33例放散液两种方法均反应,2例放散液在试管法中与A1和B细胞反应而同样的放散液做凝胶微柱法时一个和A1细胞反应,另一个只与B细胞反应。结论两种方法检测放散液结果基本是一致的,检测AIHA患者红细胞释放液抗体时用微柱法比较好,检测脐血细胞释放的同种血凝素时试管凝集法更好—些。     

Hypergammaglobulinemia can be associated with a positive direct antiglobulin test, a nonreactive eluate, and no evidence of hemolysis

To determine the cause of a positive direct antiglobulin test (DAT), blood banks routinely perform serologic tests on eluates prepared from DAT-positive red cells. Negative eluates traditionally have been suspected to be associated with drug reactions. This report confirms that the most frequent cause of a positive DAT and a nonreactive eluate is hypergammaglobulinemia. The results of 74 patient samples with positive DATs were analyzed retrospectively. Eluates prepared from the red cells of 54 patients (72.9%) reacted; eluates from 20 patients (27.1%) did not react. This latter group had identical serologic and clinical findings, suggesting that they made up a homogeneous group. In particular, the patients had a positive DAT, a negative indirect antiglobulin test, and a negative eluate; an increased serum concentration of IgG; and no evidence of hemolysis. In a subsequent study, DATs were performed prospectively on red cells from 44 consecutive patients with elevated serum IgG levels. The serum IgG concentration was highest in the three patients whose red cells had a positive DAT. The DAT also became positive in two patients treated with high-dose intravenous gammaglobulin (IV IgG). These studies indicate that a negative eluate from red cells with a positive DAT, a common serologic finding, is often caused by hypergammaglobulinemia. The authors postulate that IgG binds nonspecifically to the red cells because of the hypergammaglobulinemia.     

Detection of antibodies in acid eluates with the gel microcolumn assay

BACKGROUND: Gel microcolumns can be used to detect unexpected serum antibodies and to determine ABO blood group and Rh phenotype. DATs can also be performed with this system. The purpose of this study was to compare the gel microcolumn to the tube IAT using anti-IgG for the detection of antibodies eluted from RBCs. STUDY DESIGN AND METHODS: Acid eluates were prepared from 30 peripheral blood and 41 umbilical cord blood samples. Twelve of the 71 eluates made were from control samples (known DAT negative). Specificities of eluted antibodies were determined by both tube and gel assays with a three-cell screen plus A1 and B cells, as determined by blood type. RESULTS: Ten of 30 peripheral blood eluates were reactive in both assays. Eighteen were nonreactive in both assays, and two from patients with autoimmune hemolytic anemia were reactive by gel assays and nonreactive by tube assays. Thirty three of the 41 cord blood eluates were reactive in both assays. Eluates from 2 of the 35 DAT-positive samples reacted with A1 and B cells by the tube method but were nonreactive by the gel method. Of the 33 cord blood eluates that were reactive by both assays, antibody specificity differed for two samples. When tested by tube assay, these eluates reacted with both A1 and B cells, whereas the same eluates tested by gel assay showed one reacting with only A1 cells and the other with only B cells. CONCLUSIONS: Results of testing eluates in gel assays were similar to those obtained in tube assays. The gel assays may be better at detecting antibodies eluted from RBCs from patients with autoimmune hemolytic anemia, and tube assays may be better at detecting isohemagglutinins eluted from umbilical cord blood.     

Hemolytic anemia after kidney transplantation: a prospective analysis

BACKGROUND: Hemolysis may occur in 9% to 40% of patients after solid organ transplantation and be caused by the passenger lymphocyte syndrome (PLS). STUDY DESIGN AND METHODS: We have prospectively examined 217 kidney transplant recipients before (Day ?1) and after (up to Days +10, +20, and +30) surgery. ABO‐identical transplant was performed in 180 (82.9%) patients, while 37 (17.1%) individuals received ABO‐compatible nonidentical grafts. Direct antiglobulin tests (DATs) were performed by tube technique (polyspecific anti‐human globulin [IgG + C3d]), positive DAT samples were further tested by gel agglutination (monospecific anti‐IgG, ‐IgM, ‐IgA, or ‐C3), and eluates were prepared from DAT‐positive red blood cells (RBCs) by the dichloromethane elution test. RESULTS: We observed that 34 of 217 (15.7%) patients developed a positive DAT up to Day +30. The percentage of patients with positive DATs was significantly higher in those having ABO‐compatible nonidentical transplants compared to those that received ABO‐identical grafts (10/37 = 27.0% vs. 24/180 = 13.3%; p = 0.037). Specific RBC antibodies (anti‐A or anti‐B) were found in only 5 of 37 (13.5%) patients having ABO‐compatible nonidentical transplants who presented with clinical hemolysis. We found only three reactive eluates from 24 patients with positive DATs who received ABO‐identical transplants but had no hemolysis. CONCLUSIONS: Our data collected prospectively demonstrated that: 1) positive DATs occurred in 15.7% of all patients up to Day +30 after a kidney transplant; 2) the DAT positivity occurred up to Day +10 in 9.7% of all transplanted patients; 3) the majority of the transplant recipients with a positive DAT had a nonreactive RBC eluate; and 4) PLS was the cause of a positive DAT in 13.5% of patients submitted to ABO‐compatible nonidentical kidney transplants.     

The evaluation of a positive direct antiglobulin test in pretransfusion testing

The results of serologic studies on 879 blood samples with a positive direct antiglobulin test (DAT) are presented. All blood samples were from patients who were either anemic, for reasons other than blood loss, recently transfused, or had serum antibodies detected during routine pretransfusion tests. Blood samples from only 81 of the patients included in this study had serologically reactive eluates (64 autoantibodies, three antibodies to penicillin and cephalothin treated red blood cells, three passively acquired anti-A antibodies, and 11 transfusion-induced alloantibodies). The eluted antibodies were also detected in the serum by routine pretransfusion tests in 13 of the patients whose red blood cells eluted autoantibodies, and in five of the patients whose red blood cells eluted transfusion-induced alloantibodies. All but one of the 11 transfusion-induced alloantibodies were detected within 14 days posttransfusion. Based on these findings, a cost-effective and safe approach to the management of blood samples with a positive DAT would be to restrict the preparation and testing of eluates to those samples from recently transfused patients. It is the contention of the authors that the incorporation of the DAT in pretransfusion testing should primarily serve to detect alloantibody formation before such antibodies are evident in the serum, and should not be used to screen patients for unsuspected autoimmune hemolytic anemia. Furthermore, the authors question the necessity for blood banks to routinely perform an autocontrol on all blood samples from prospective transfusion recipients.     

Comparison of a gel microcolumn assay with the conventional tube test for red blood cell alloantibody titration

BACKGROUND: Titration is a semiquantitative method used to estimate red blood cell (RBC) alloantibody reactivity. The conventional tube test (CTT) technique is the traditional method for performing titration studies. The gel microcolumn assay (GMA) is also a sensitive method to detect RBC alloantibodies. The aim of this study was to compare a GMA with the CTT technique in the performance of Rh and K alloantibody titration. STUDY DESIGN AND METHODS: Patient serum samples that contained an RBC alloantibody with a singular specificity were identified by routine blood bank workflow. Parallel titration studies were performed on these samples by both the CTT method and a GMA (ID‐Micro Typing System anti‐IgG gel card, Micro Typing Systems, Inc., an Ortho‐Clinical Diagnostics Company). RESULTS: Forty‐eight samples were included, including 11 anti‐D, five anti‐c, 13 anti‐E, one anti‐C, three anti‐e, and 15 anti‐K. Overall, the two methods generated identical results in 21 of 48 samples. For 42 samples (87.5%) the two methods generated results that were within one serial dilution, and for the remaining six samples, results were within two dilutions. CONCLUSION: GMA systems may perform comparably to the CTT in titrating alloantibodies to Rh and Kell antigens.     

乙型肝炎患者直接抗球蛋白试验临床意义的探讨

目的探讨直接抗球蛋白试验(DAT)在乙型肝炎患者中的临床意义。方法分别应用柱凝集法(CAT)和传统试管法(CTT)对50名慢性HBV感染无症状携带者、42名慢性乙型肝炎(慢乙肝)患者和52名慢性重型肝炎(慢重肝)患者红细胞膜吸附的抗体进行检测。结果慢重肝患者红细胞计数及血红蛋白(Hb)浓度均明显低于慢乙肝、无症状携带者和正常对照者(P<0.01);CAT法、CTT法分别检测正常对照和无症状携带者DAT阳性率均为0;CAT法检测慢乙肝和慢重肝患者DAT阳性率分别为14.3%和84.3%,而CTT法的DAT阳性率分别为9.5%和50%;DAT阳性的慢乙肝和慢重肝患者Hb浓度均明显低于相应DAT阴性患者,随着DAT阳性程度的增加,慢重肝患者红细胞计数和Hb浓度均逐渐降低,DAT阳性程度与Hb浓度呈明显的负相关(r=-0.68,P<0.01)。结论DAT阳性的乙型肝炎患者Hb水平明显降低,表明乙型肝炎患者贫血的产生可能与红细胞抗体的存在有关。     

Is it necessary to add the eluate testing to the direct antiglobulin test to improve the detection of maternal erythrocyte alloantibodies?

BACKGROUNDThe screening of umbilical cord blood samples by the Direct Antiglobulin Test (DAT) is the reference tool for the identification of maternal erythrocyte alloantibodies present in erythrocytes; however, its diagnostic usefulness is controversial.OBJECTIVETo evaluate the diagnostic validity, safety, and efficiency of the eluate testing (detection of antibody in erythrocyte eluates by the Indirect Antiglobulin Test/IAT) in cord blood samples for detection of maternal erythrocyte alloantibodies in comparison with the DAT.MATERIALS AND METHODSEvaluation study of diagnostic tests. DAT and eluate testing were performed in 306 cord blood samples from neonates born to mothers admitted at Clínica Somer in Rionegro, Colombia; then, antibodies present in the eluates were identified with erythrocyte panels. Percentage of positive results by DAT and IAT were compared with the Pearson's chi-square test and the agreement between both assays with the Cohen's kappa coefficient. The diagnostic sensitivity, specificity, safety, and efficiency of the eluate testing were calculated, taking into account the use of DAT as an imperfect reference test.RESULTSThe DAT detected alloantibodies in 6.21% of samples and the eluate testing in 14.1 %; the strength of agreement between both tests was moderate (k = 0.56) due to 25 discrepancies. The eluate testing showed sensitivity and specificity of 98.83 % and 92.31 % respectively, and a negative predictive value of 99.9 %. The diagnostic efficiency was sufficient for detection of maternal erythrocyte alloantibodies. The antibodies identified in the erythrocyte eluates were anti-A or anti-B (79.5 %), anti-D (136%), anti-C (2,3%), and anti-Fya (2,3%).CONCLUSIONThe eluate testing in cord blood samples is a valid, safe, and efficient test for the diagnosis of maternal erythrocyte alloantibodies.     

The evaluation of a positive direct antiglobulin test (autocontrol) in pretransfusion testing revisited

Direct antiglobulin tests (DATs) using anti-IgG were performed on 65,049 blood samples from prospective transfusion recipients; 3570 tests (5.49%) were positive. Using criteria published previously (primarily excluding patients not transfused within the preceding 14 days), 778 samples from other than neonatal patients were selected for further evaluation. Eluates that did not react were obtained on 518 (66.6%) of these samples. Warm-reactive autoantibodies were apparent in 192 eluates, while 16 contained drug-related antibodies, anti-A or anti-B from prior transfusion with ABO mismatched blood components, or anti-D passively acquired from immune serum globulin. Fifty-two eluates contained alloantibodies; however, in only six of these cases did the corresponding serum lack unexpected alloantibodies, as determined by routine pretransfusion studies. Three additional weakly reactive clinically significant alloantibodies were detected solely through additional serum tests performed on DAT-positive samples. On the basis of these findings, the DAT had a low predictive value when used to detect the early manifestations of an immune response to recently transfused red cells. Elimination of the autocontrol from routine pretransfusion testing, therefore, carries minimal risk to patients yet will undoubtedly contribute to the containment of health care costs. Moreover, the risk is lower than that associated with the elimination of the antiglobulin crossmatch.     

Comparison of DATs using traditional tube agglutination to gel column and affinity column procedures

BACKGROUND: Detection of immunoglobulin or complement bound to RBCs by using the DAT is valuable in the diagnosis of immune-mediated hemolytic anemia. Traditionally, the DAT has been performed by tube agglutination using anti-IgG or anti-C3d. The purpose of this study was to compare the tube agglutination DAT to gel microcolumn, affinity microcolumn, and flow cytometric DATs on RBCs coated in vitro and on patient RBC samples. STUDY DESIGN AND METHODS: RBCs from 84 patients were assessed by tube agglutination DAT, one gel microcolumn DAT, and two affinity microcolumn DATs. One affinity microcolumn assay was unmodified and one was modified by the addition of polyspecific antiglobulin or anti-IgG as a secondary antibody. RBCs from 15 of the 84 patients underwent analysis by flow cytometry with fluorescence-labeled anti-IgG. The assays were also compared by using D+ RBCs sensitized with serially adjusted concentrations of anti-D. RESULTS: Both tube agglutination and gel microcolumn DATs were positive in 49 patient samples; both assays were negative in 20 samples, and the results were discordant in 15. Gel microcolumn DATs were more likely than were tube agglutination DATs to detect IgG on RBCs. Affinity microcolumn DATs were less likely than gel microcolumn or tube agglutination DATs to detect IgG on RBCs. Flow cytometry results were the same as gel microcolumn results in 12 of 15 patient samples and the same as tube agglutination results in 13 of 15. Tube agglutination and both affinity microcolumn assays reacted with RBCs coated with anti-D that was diluted 1-in-100. The gel microcolumn and flow cytometry assays reacted with RBCs coated with anti-D diluted 1-in-400. There was no correlation between tube agglutination and gel microcolumn DATs in detecting bound C3d. CONCLUSION: Detection of IgG bound to RBCs was not consistent with the methods described. Gel microcolumn DATs were more sensitive than tube agglutination and affinity microcolumn DATs. Given the varied results of these assays, reference laboratories should not rely on a single method for DATs. More comprehensive testing should be performed when the tube agglutination DAT is negative in a patient with suspected immune-mediated hemolytic anemia. Further comparisons are necessary to determine the proficiency of flow cytometric assays.     

The role of the elution in antibody investigations

BACKGROUND: The direct antiglobulin test (DAT) commonly detects immunoglobulin G (IgG) molecules or complement fragments on the red blood cell (RBC) surface. If IgG antibodies are present then elution procedures can be performed to identify the specificity of these antibodies. Our reference laboratory performs elutions on the RBCs of those patients who have received cellular blood products in the past 30 days and have either a newly identified positive DAT with anti-IgG or the agglutination strength is increased over a previous DAT and if ordered by a clinician regardless of transfusion history. This study questioned how frequently elutions contributed novel serologic information under our reference laboratory's current policy or whether elutions should be performed in more selective serologic conditions.
STUDY DESIGN AND METHODS: Recipients whose RBCs underwent eluate testing were identified from the blood bank's database and information about the antecedent DAT and antibody detection test and eluate was recorded.
RESULTS: In total 648 eluates were evaluated and 82 of 648 (12.7%) revealed a novel antibody not present in the serum (an informative eluate). In 2 of 82 informative eluates non–anti-A/B alloantibodies that were not present in the serum were detected: one example each of anti-D and anti-E. Both were associated with a microscopically positive antecedent DAT. The rate of an informative eluate was higher when the antibody detection test was negative.
CONCLUSION: The strength of the DAT does not indicate the likelihood of an informative eluate. Performing an eluate when the antibody detection test is positive has limited value.     

Evaluation of the ID-gel test for antibody screening and identification

Summary. A gel technique for the detection of red blood cell (rbc) antigen-antibody reactions was evaluated for use in antenatal antibody screening and identification procedures. The evaluation was undertaken on 3,900 random antenatal samples. Results obtained in the gel test system were compared with those obtained from parallel testing using conventional serological methods. The ID gel system detected 148 (3·7%) red cell antibodies, compared with 95 (2·4%) using traditional techniques. The number of non-specific antibodies and false-positive screens were reduced using the gel test system. Antibody titres performed using the gel system were more sensitive than with our tube 1AT method. The gel system was easy to use and gave reliable, reproducible results. Antibody detection rates were enhanced compared with our existing routine techniques.     

Positive antiglobulin tests due to intravenous immunoglobulin in patients who received bone marrow transplant

To investigate an increased frequency of positive direct (DAT) and indirect (IAT) antiglobulin tests in bone marrow transplant (BMT) patients who received intravenous immunoglobulin (IVIG), serologic testing was performed weekly on blood samples from 94 consecutive BMT patients. Group 1 (47 patients) did not receive IVIG. Group II (47 patients) received high-dose IVIG as prophylaxis for cytomegalovirus infections. Before transplantation no alloantibodies were found in the serums of 92 patients and anti-E was found in the serums of two patients. DATs were negative in all patients before BMT. Four percent of Group I had a positive IAT and 13 percent had a positive DAT. In contrast, 25.5 percent of Group II patients had a positive IAT and 49 percent had a positive DAT, usually within 1 week after initiation of IVIG therapy (p less than 0.001). Antibodies identified in serums and eluates of patients in Group I were anti-A and anti-B. Antibodies identified in serums and eluates of patients in Group II were anti-A, -B, -D, and -K. Twenty-one lots of IVIG were tested and antibodies identified were anti-A, -B, -D, and -K. The data suggest that the higher frequency of positive serologic tests in Group II was due to passively acquired antibodies from high-dose IVIG.     

Lower hemoglobin levels in human immunodeficiency virus-infected patients with a positive direct antiglobulin test (DAT): relationship with DAT strength and clinical stages

BACKGROUND: There are conflicting opinions regarding the effect of positive direct antiglobulin test (DAT) on hemoglobin (Hb) levels in human immunodeficiency virus-infected (HIV+) patients. STUDY DESIGN AND METHODS: A total of 166 samples from HIV+ outpatients were studied. The DAT was performed with the tube test and column agglutination technology (CAT). RESULTS: The DAT was positive in 18.67 percent with the tube method and 33.73 percent with the CAT. Patients with DAT-positive results showed lower Hb levels than DAT-negative patients, 12.3 g per dL versus 14.3 g per dL (p = 0.0002). The univariate logistic regression enabled us to study the phenomenon better and fit the probability of having a DAT-positive result on the basis of the Hb levels. The relationship between the CAT and the tube test when washing the red blood cells (RBC) at 4 degrees C was stronger than when washing these at room temperature (phi = 0.8156; p = 0.000). The Hb levels were significantly lower in the positive DATs of Stage C (acquired immune deficiency syndrome [AIDS]) and Stage B (symptomatic non-AIDS patients), which showed decreasing Hb values for increasing agglutination strengths (p = 0.000). Anemia was related with the DAT results (odds ratio [OR], 8.005; p = 0.000) but not to the AIDS condition (OR, 1.741; p = 0.221). DISCUSSION: Our study indicates that the DAT-positive results may be specifically related to lower Hb levels in HIV+ patients. The immunologic RBC clearance could be part of the anemic multifactorial condition in HIV+ patients.     

Incidence of antibody formation and positive direct antiglobulin tests in a multitransfused hemodialysis population

In order to determine the degree and significance of red cell antibody production by dialysis patients, two groups of patients were studied retrospectively. One hundred and five randomly selected dialysis patients (Group I) receiving a total of 1074 units of blood were reviewed, as were 38 patients who were given frozen-thawed red cells because of intractable nonhemolytic febrile reactions following transfusions of red cells stored conventionally (Group II). Eleven patients in Group I produced alloantibodies: nine after the start of dialysis. Of these, two patients had antibodies that were judged clinically insignificant. Eleven of 38 patients in Group II had red cell alloantibodies at the time of study, four of which were judged clinically significant. The direct antiglobulin test (DAT) was positive in 14 patients in Group I and eight patients in Group II for an overall percentage of 15. The cause of the positive DAT was determined in eluates for 26 percent of the cases studied. Clinically significant antibodies were produced by 6.7 percent of randomly selected dialysis patients (Group I). This incidence is lower than other chronically transfused patient populations reported, but higher than that reported in transfused patients at large. The incidence of positive DATs was higher than in some populations reported but not others.     

凝聚胺法与微柱凝聚法检测不规则抗体的对比分析

目的探讨凝聚胺法与微柱凝聚法在不规则抗体筛选中的价值对比。方法对2010～2011年江门市新会区人民医院6 720例预约输血患者,用凝聚胺法与微柱凝聚法分别进行不规则抗体筛查,阳性结果再用谱细胞通过抗人球蛋白方法进行特异性检测。结果用微柱凝聚法筛查出不规则抗体阳性28例,阳性率为0.42%,而凝聚胺检测阳性26例,阳性率仅为0.39%,两种方法比较差异无统计学意义（P〉0.05）。其中Rh系统占总不规则抗体比例为57.1%,分别为抗-D 5例,抗-E 7例,抗-C 2例,抗-Ec 2例。结论凝聚胺法与微柱凝聚法都适用于临床筛查不规则抗体,微柱凝聚法比凝聚胺法更有利于大规模自动化筛查,对于有条件的大医院更适合临床输血前的应用和相关疾病的诊断,而凝聚胺法在基层或者临床急诊上也可合理开展。     

Chloroquine dissociation of antigen-antibody complexes. A new technique for typing red blood cells with a positive direct antiglobulin test

We have investigated a method using the quinoline derivative chloroquine diphosphate (200 mg/ml, pH 5.0) to dissociate antibody without denaturing red blood cell antigens. All samples treated with chloroquine diphosphate demonstrated some dissociation of the coating immunoglobulin, and in most cases, the ability to dissociate the coating immunoglobulin was related to the strength of the direct antiglobulin test (DAT). Complete dissociation of antibody was observed in 22 of 40 strongly in vitro sensitized samples and 47 of 56 in vivo sensitized specimens, with no apparent loss of ABH, Rh, MNSs, P1, Lewis, Kell, Duffy, or Kidd antigens. We have found the chloroquine dissociation technique to be of value in the examination of red blood cells with a positive DAT, either for the qualitative or quantitative expression of antigens.     

抗人球蛋白试验阳性与恶性血液病的关联性及输血治疗的探讨

目的：恶性血液病常合并自身免疫性溶血性贫血,对血液科抗人球蛋白试验阳性患者进行统计分析,探讨疾病的关联性和输血治疗的方向。方法：采用微柱凝集法对患者血样做抗人球蛋白试验,包括直接抗人球蛋白试验（DAT）和间接抗人球蛋白试验（IAT）。结果：263例抗人球蛋白试验中阳性为69例,直抗（DAT）和间抗（IAT）均阳性有4例,单纯DAT阳性65例。其中原发性阳性率占7．2％,继发性占17．5％。结论：恶性血液病会继发自身免疫性溶血,并且对溶血性贫血的患者先申请做直接和间接抗人球蛋白试验,清楚发生溶血的原因后再申请用何种成分红细胞输血治疗,以达到理想的输血效果。     

试管凝集试验与虎红平板凝集试验对布鲁氏杆菌病的诊断价值

目的研究试管凝集试验与虎红平板凝集试验对布鲁氏杆菌病的诊断价值。方法于2017年1月至2019年12月将清丰县疾病预防控制中心接受布鲁氏杆菌病筛查的120例疑似布鲁氏杆菌病患者纳入研究,对血液标本进行试管凝集试验、虎红平板凝集试验,比较试管凝集试验与虎红平板凝集试验的诊断结果。结果在布鲁氏杆菌病诊断中,参照布鲁氏杆菌病综合检测结果,虎红平板凝集试验的灵敏度、阴性预测值均高于试管凝集试验,而试管凝集试验的特异度、阳性预测值均高于虎红平板凝集试验(P<0.05),试管凝集试验与虎红平板凝集试验的准确度无显著差异(P>0.05)。试管凝集试验、虎红平板凝集试验诊断结果与布鲁氏杆菌病综合检测结果之间均呈高度一致(Kappa=0.807、0.823)。结论试管凝集试验、虎红平板凝集试验在布鲁氏杆菌病诊断中具有各自优势,临床诊断时可结合两种凝集试验方法进行综合诊断,以提高诊断的准确性。     

Clinical application of a flow cytometric direct antiglobulin test

BACKGROUND: The clinical application of flow cytometric direct antiglobulin test (FC-DAT) has rarely been evaluated for patients with various diseases including immune and nonimmune hemolytic anemia.
STUDY DESIGN AND METHODS: Blood samples from 380 patients with a variety of diseases were studied using the tube direct DAT and FC-DAT. The results of tube DAT and FC-DAT were compared. The predictive values of DAT for hemolysis were evaluated.
RESULTS: Of 57 patients with autoimmune hemolytic anemia (AIHA), 6 of the 17 with a negative tube DAT (immunoglobulin G [IgG]) had a positive FC-DAT (IgG) and 23 of the 36 patients with a negative tube DAT (complement 3d [C3d]) had a positive FC-DAT (C3d). In 57 patients with AIHA, the incidence of positive results of FC-DAT (IgG) and tube DAT (IgG) were similar (42 positive vs. 40 positive); but in 323 patients without AIHA, the incidence of positive FC-DATs (IgG) was higher than that of tube DAT (IgG; 47 positive vs. 9 positive). The higher incidence of positive FC-DAT (C3d) than that of tube DAT (C3d) was seen in patients with AIHA (42 positive vs. 21 positive) as well as in patients without AIHA (61 positive vs. 5 positive). Both DAT (IgG) and DAT (C3d) positive has highest positive predictive value for hemolysis, followed by DAT (IgG) alone positive and DAT (C3d) alone positive.
CONCLUSIONS: FC-DAT is a complementary test for diagnosing AIHA. There is a synergistic effect of the red blood cell–bound IgG and complement in predicting hemolysis.