The Experts below are selected from a list of 6543 Experts worldwide ranked by ideXlab platform
Jeffrey S Ginsberg - One of the best experts on this subject based on the ideXlab platform.
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2008Co-Authors: Weeshian Chan, Sanjeev Chunilal, Agnes Y Y Lee, Mark Crowther, Jeffrey S GinsbergAbstract:Along with compression ultrasonography of the legs, widely viewed as the preferred test for diagnosing deep venous thrombosis (DVT), D-dimer testing frequently is carried out because it is highly sensitive and a negative result may preclude the need for further testing. The latter test has, however, not been evaluated for diagnosing DVT in pregnancy because of its relatively low specificity. This study sought to determine the utility of the easily performed SimpliRED assay for diagnosing DVT in pregnant women. A prospective cohort study, conducted at university-affiliated Canadian hospitals, enrolled 149 consecutive pregnant women suspected of having DVT. They underwent compression ultrasonography on days 0, 3, and 7, and were followed up clinically after 3 months to determine the presence or absence of DVT. Whole blood samples were obtained at initial presentation for the SimpliRED assay. In this rapid test, blood is mixed with a conjugate of monoclonal antibody to D-dimer linked to a monoclonal antibody that binds to the red Cell surface. High levels of D-dimer cause Agglutination. DVT was diagnosed in 13 of the 149 participants (8.7%). All cases but one were diagnosed from initial compression ultrasonography. The SimpliRED assay was 100% sensitive and 60% specific, and had a negative predictive value of 100%. When stratifying the results of D-dimer testing by the presence or absence of patient risk factors, women having positive D-dimer test results in the first trimester of pregnancy had a high prevalence of DVT (62.5%) regardless of whether or not risk factors were present. Among pregnant women in whom DVT was not diagnosed, the assay was positive in no women in the first trimester, 24% of second-trimester pregnancies, and 51% of women in the third trimester. These findings indicate that the SimpliRED D-dimer assay is clinically useful in pregnant women suspected of having DVT. A negative result effectively excludes this diagnosis. The test appears to be useful for at least the first 2 trimesters of pregnancy.
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2007Co-Authors: Weeshian Chan, Sanjeev Chunilal, Mark Crowther, Marc A Rodger, Jeffrey S GinsbergAbstract:Because D-dimer levels increase in pregnancy, it was thought that D-dimer testing is less accurate for diagnosing venous thromboembolism in pregnant women than in nonpregnant women. In this observa...
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2007Co-Authors: Weeshian Chan, Sanjeev Chunilal, Mark A Crowther, Marc Rodger, Jeffrey S GinsbergAbstract:Background: D-Dimer testing is often used with compression ultrasonography for the diagnosis of deep venous thrombosis (DVT) in nonpregnant patients. The D-dimer test is highly sensitive, and a negative result can obviate the need for further testing for DVT. This test has not been studied for DVT diagnosis in pregnancy because its specificity was deemed too poor. Objective: To determine the sensitivity and specificity and assess the utility of the SimpliRED assay (Agen Biomedical, Brisbane, Australia) for the diagnosis of DVT in pregnant women. Design: Prospective cohort study. Setting: 5 tertiary university-affiliated Canadian hospitals providing care to obstetric patients. Patients: 149 consecutive pregnant women with suspected DVT who presented to 1 of the participating centers over 5 years. Intervention: Participating women were tested with compression leg ultrasonography (single or serially on days 0, 3, and 7) and received 3 months' clinical follow-up for the presence or absence of DVT. Whole blood was tested with the SimpliRED assay at initial presentation, and results were correlated with ultrasonography and clinical findings for the presence or absence of DVT. Measurements: The sensitivity, specificity, and negative predictive value of the SimpliRED assay were calculated, along with the prevalence of false-positive SimpliRED assay results (with 95% Cls). Results: The prevalence of DVT in the cohort was 8.7% (95% Cl, 5.2% to 14.4%). The sensitivity of the SimpliRED assay was 100% (Cl, 77% to 100% [13 of 13 patients]), the specificity was 60% (Cl, 52% to 68% [81 of 135]), and the negative predictive value was 100% (Cl, 95% to 100% [81 of 81]). The SimpliRED assay was positive in 0% (Cl, 0% to 60%), 24% (Cl, 14% to 37%), and 51% (Cl, 40% to 61%) of women in the first, second, and third trimesters, respectively, among pregnant patients in whom DVT was not diagnosed. Limitations: The prevalence of DVT in the cohort was low, resulting in wide Cls. The clinician's previous impression was used to determine pretest probability in the absence of a validated clinical prediction rule for pregnant women. Conclusion: The SimpliRED assay may be useful in pregnancy because a normal result excludes DVT and occurs frequently enough to be clinically helpful.
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the sensitivity and specificity of a red blood Cell Agglutination d dimer assay for venous thromboembolism when performed on venous blood
2002Co-Authors: Sanjeev Chunilal, Patrick Brilledwards, Pamela Stevens, Jody P Joval, Joanne Mcginnis, Mala Rupwate, Jeffrey S GinsbergAbstract:Background Studies evaluating the accuracy of the SimpliRED D-dimer assay for venous thromboembolism (VTE) have used a capillary fingerstick blood sample, which requires the test to be performed immediately at the bedside. Initial studies showed a sensitivity for VTE of 90% to 95% when the assay was performed by a finite number of experienced health care workers. However, because of the test's subjectivity, misinterpretation of the result is possible when performed by inexperienced staff. Recent reports by other investigators indicated a low sensitivity of this assay for VTE and noted a reduction in sensitivity (84%) for pulmonary embolism. Objective To determine the sensitivity and specificity of the D-dimer test performed in the laboratory by experienced technologists on venous whole-blood samples in routine collection tubes. If D-dimer testing results accurately detect VTE when performed in this manner, concerns about the sensitivity of this assay would be solved. Methods One hundred forty-eight consecutive patients with suspected VTE underwent D-dimer testing at the bedside using a fingerstick sample and venous blood collected into a plain tube. Venous blood was also collected into tubes containing tri-potassium EDTA, sodium citrate, or a combination of lithium and heparin for D-dimer testing in the laboratory. In addition, the EDTA tube was refrigerated overnight at 4°C for retesting at approximately 24 hours. The presence or absence of VTE was determined by means of objective results of testing and a 3-month follow-up. Results Thirty-four subjects (23%) had confirmed VTE (25 with deep vein thrombosis; 9 with pulmonary embolism). All laboratory venous blood D-dimer results showed sensitivities of 97%, specificities of 61% to 64%, and negative predictive values of 99%, compared with 88%, 71%, and 95%, respectively, when the results were obtained by means of fingerstick at the bedside. Conclusions The SimpliRED D-dimer assay performed in the laboratory on venous blood, collected into any of 3 routine laboratory tubes, is sensitive and moderately specific for VTE. Based on this study, immediate bedside testing (particularly by inexperienced personnel) under suboptimal conditions is unnecessary. Furthermore, the high sensitivity of refrigerated EDTA samples allows specimens to be stored or transported (on ice at 4°C) for testing for 24 hours after collection.
Zack Z Wang - One of the best experts on this subject based on the ideXlab platform.
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a rapid point of care red blood Cell Agglutination assay detecting antibodies against sars cov 2
2021Co-Authors: Robert L Kruse, Yuting Huang, Heather Smetana, Eric A Gehrie, Timothy K Amukele, Aaron A R Tobian, Heba H Mostafa, Zack Z WangAbstract:The COVID-19 pandemic has caused significant morbidity and mortality. There is an urgent need for serological tests to detect antibodies against SARS-CoV-2, which could be used to assess past infection, evaluate responses to vaccines in development, and determine individuals who may be protected from future infection. Current serological tests developed for SARS-CoV-2 rely on traditional technologies such as enzyme-linked immunosorbent assays (ELISA) and lateral flow assays, which have not scaled to meet the demand of hundreds of millions of antibody tests so far. Herein, we present an alternative method of antibody testing that depends on one protein reagent being added to patient serum/plasma or whole blood with direct, visual readout. Two novel fusion proteins, RBD-2E8 and B6-CH1-RBD, were designed to bind red blood Cells (RBCs) via a single-chain variable fragment (scFv), thereby displaying the receptor-binding domain (RBD) of SARS-CoV-2 spike protein on the surface of RBCs. Mixing mammalian-derived RBD-2E8 and B6-CH1-RBD with convalescent COVID-19 patient serum and RBCs led to visible hemAgglutination, indicating the presence of antibodies against SARS-CoV-2 RBD. B6-CH1-RBD made in bacteria was not as effective in inducing Agglutination, indicating better recognition of RBD epitopes from mammalian Cells. Given that our hemAgglutination test uses methods routinely used in hospital clinical labs across the world for blood typing, we anticipate the test can be rapidly deployed at minimal cost. We anticipate our hemAgglutination assay may find extensive use in low-resource settings for detecting SARS-CoV-2 antibodies.
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a rapid point of care red blood Cell Agglutination assay for detecting antibodies against sars cov 2
2020Co-Authors: Robert L Kruse, Yuting Huang, Heather Smetana, Eric A Gehrie, Timothy K Amukele, Aaron A R Tobian, Heba H Mostafa, Zack Z WangAbstract:The COVID-19 pandemic has brought the world to a halt, with cases observed around the globe causing significant mortality. There is an urgent need for serological tests to detect antibodies against SARS-CoV-2, which could be used to assess the prevalence of infection, as well as ascertain individuals who may be protected from future infection. Current serological tests developed for SARS-CoV-2 rely on traditional technologies such as enzyme-linked immunosorbent assays (ELISA) and lateral flow assays, which may lack scalability to meet the demand of hundreds of millions of antibody tests in the coming year. Herein, we present an alternative method of antibody testing that just depends on one protein reagent being added to patient serum/plasma or whole blood and a short five-minute assay time. A novel fusion protein was designed that binds red blood Cells (RBC) via a single-chain variable fragment (scFv) against the H antigen and displays the receptor-binding domain (RBD) of SARS-CoV-2 spike protein on the surface of RBCs. Upon mixing of the fusion protein, RBD-scFv with recovered COVID-19 patient serum and RBCs, we observed Agglutination of RBCs, indicating the patient developed antibodies against SARS-CoV-2 RBD. Given that the test uses methods routinely used in hospital clinical labs across the world, we anticipate the test can be rapidly deployed with only the protein reagent required at projected manufacturing cost at U.S. cents per test. We anticipate our Agglutination assay may find extensive use in low-resource settings for detecting SARS-CoV-2 antibodies.
Sanjeev Chunilal - One of the best experts on this subject based on the ideXlab platform.
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2008Co-Authors: Weeshian Chan, Sanjeev Chunilal, Agnes Y Y Lee, Mark Crowther, Jeffrey S GinsbergAbstract:Along with compression ultrasonography of the legs, widely viewed as the preferred test for diagnosing deep venous thrombosis (DVT), D-dimer testing frequently is carried out because it is highly sensitive and a negative result may preclude the need for further testing. The latter test has, however, not been evaluated for diagnosing DVT in pregnancy because of its relatively low specificity. This study sought to determine the utility of the easily performed SimpliRED assay for diagnosing DVT in pregnant women. A prospective cohort study, conducted at university-affiliated Canadian hospitals, enrolled 149 consecutive pregnant women suspected of having DVT. They underwent compression ultrasonography on days 0, 3, and 7, and were followed up clinically after 3 months to determine the presence or absence of DVT. Whole blood samples were obtained at initial presentation for the SimpliRED assay. In this rapid test, blood is mixed with a conjugate of monoclonal antibody to D-dimer linked to a monoclonal antibody that binds to the red Cell surface. High levels of D-dimer cause Agglutination. DVT was diagnosed in 13 of the 149 participants (8.7%). All cases but one were diagnosed from initial compression ultrasonography. The SimpliRED assay was 100% sensitive and 60% specific, and had a negative predictive value of 100%. When stratifying the results of D-dimer testing by the presence or absence of patient risk factors, women having positive D-dimer test results in the first trimester of pregnancy had a high prevalence of DVT (62.5%) regardless of whether or not risk factors were present. Among pregnant women in whom DVT was not diagnosed, the assay was positive in no women in the first trimester, 24% of second-trimester pregnancies, and 51% of women in the third trimester. These findings indicate that the SimpliRED D-dimer assay is clinically useful in pregnant women suspected of having DVT. A negative result effectively excludes this diagnosis. The test appears to be useful for at least the first 2 trimesters of pregnancy.
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2007Co-Authors: Weeshian Chan, Sanjeev Chunilal, Mark Crowther, Marc A Rodger, Jeffrey S GinsbergAbstract:Because D-dimer levels increase in pregnancy, it was thought that D-dimer testing is less accurate for diagnosing venous thromboembolism in pregnant women than in nonpregnant women. In this observa...
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2007Co-Authors: Weeshian Chan, Sanjeev Chunilal, Mark A Crowther, Marc Rodger, Jeffrey S GinsbergAbstract:Background: D-Dimer testing is often used with compression ultrasonography for the diagnosis of deep venous thrombosis (DVT) in nonpregnant patients. The D-dimer test is highly sensitive, and a negative result can obviate the need for further testing for DVT. This test has not been studied for DVT diagnosis in pregnancy because its specificity was deemed too poor. Objective: To determine the sensitivity and specificity and assess the utility of the SimpliRED assay (Agen Biomedical, Brisbane, Australia) for the diagnosis of DVT in pregnant women. Design: Prospective cohort study. Setting: 5 tertiary university-affiliated Canadian hospitals providing care to obstetric patients. Patients: 149 consecutive pregnant women with suspected DVT who presented to 1 of the participating centers over 5 years. Intervention: Participating women were tested with compression leg ultrasonography (single or serially on days 0, 3, and 7) and received 3 months' clinical follow-up for the presence or absence of DVT. Whole blood was tested with the SimpliRED assay at initial presentation, and results were correlated with ultrasonography and clinical findings for the presence or absence of DVT. Measurements: The sensitivity, specificity, and negative predictive value of the SimpliRED assay were calculated, along with the prevalence of false-positive SimpliRED assay results (with 95% Cls). Results: The prevalence of DVT in the cohort was 8.7% (95% Cl, 5.2% to 14.4%). The sensitivity of the SimpliRED assay was 100% (Cl, 77% to 100% [13 of 13 patients]), the specificity was 60% (Cl, 52% to 68% [81 of 135]), and the negative predictive value was 100% (Cl, 95% to 100% [81 of 81]). The SimpliRED assay was positive in 0% (Cl, 0% to 60%), 24% (Cl, 14% to 37%), and 51% (Cl, 40% to 61%) of women in the first, second, and third trimesters, respectively, among pregnant patients in whom DVT was not diagnosed. Limitations: The prevalence of DVT in the cohort was low, resulting in wide Cls. The clinician's previous impression was used to determine pretest probability in the absence of a validated clinical prediction rule for pregnant women. Conclusion: The SimpliRED assay may be useful in pregnancy because a normal result excludes DVT and occurs frequently enough to be clinically helpful.
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the sensitivity and specificity of a red blood Cell Agglutination d dimer assay for venous thromboembolism when performed on venous blood
2002Co-Authors: Sanjeev Chunilal, Patrick Brilledwards, Pamela Stevens, Jody P Joval, Joanne Mcginnis, Mala Rupwate, Jeffrey S GinsbergAbstract:Background Studies evaluating the accuracy of the SimpliRED D-dimer assay for venous thromboembolism (VTE) have used a capillary fingerstick blood sample, which requires the test to be performed immediately at the bedside. Initial studies showed a sensitivity for VTE of 90% to 95% when the assay was performed by a finite number of experienced health care workers. However, because of the test's subjectivity, misinterpretation of the result is possible when performed by inexperienced staff. Recent reports by other investigators indicated a low sensitivity of this assay for VTE and noted a reduction in sensitivity (84%) for pulmonary embolism. Objective To determine the sensitivity and specificity of the D-dimer test performed in the laboratory by experienced technologists on venous whole-blood samples in routine collection tubes. If D-dimer testing results accurately detect VTE when performed in this manner, concerns about the sensitivity of this assay would be solved. Methods One hundred forty-eight consecutive patients with suspected VTE underwent D-dimer testing at the bedside using a fingerstick sample and venous blood collected into a plain tube. Venous blood was also collected into tubes containing tri-potassium EDTA, sodium citrate, or a combination of lithium and heparin for D-dimer testing in the laboratory. In addition, the EDTA tube was refrigerated overnight at 4°C for retesting at approximately 24 hours. The presence or absence of VTE was determined by means of objective results of testing and a 3-month follow-up. Results Thirty-four subjects (23%) had confirmed VTE (25 with deep vein thrombosis; 9 with pulmonary embolism). All laboratory venous blood D-dimer results showed sensitivities of 97%, specificities of 61% to 64%, and negative predictive values of 99%, compared with 88%, 71%, and 95%, respectively, when the results were obtained by means of fingerstick at the bedside. Conclusions The SimpliRED D-dimer assay performed in the laboratory on venous blood, collected into any of 3 routine laboratory tubes, is sensitive and moderately specific for VTE. Based on this study, immediate bedside testing (particularly by inexperienced personnel) under suboptimal conditions is unnecessary. Furthermore, the high sensitivity of refrigerated EDTA samples allows specimens to be stored or transported (on ice at 4°C) for testing for 24 hours after collection.
Ester Boix - One of the best experts on this subject based on the ideXlab platform.
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insights into the antimicrobial mechanism of action of human rnase6 structural determinants for bacterial Cell Agglutination and membrane permeation
2016Co-Authors: David Pulido, Mohammed Moussaoui, Javier Arranztrullen, Guillem Pratsejarque, Diego Velazquez, Marc Torrent, Ester BoixAbstract:Human Ribonuclease 6 is a secreted protein belonging to the ribonuclease A (RNaseA) superfamily, a vertebrate specific family suggested to arise with an ancestral host defense role. Tissue distribution analysis revealed its expression in innate Cell types, showing abundance in monocytes and neutrophils. Recent evidence of induction of the protein expression by bacterial infection suggested an antipathogen function in vivo. In our laboratory, the antimicrobial properties of the protein have been evaluated against Gram-negative and Gram-positive species and its mechanism of action was characterized using a membrane model. Interestingly, our results indicate that RNase6, as previously reported for RNase3, is able to specifically agglutinate Gram-negative bacteria as a main trait of its antimicrobial activity. Moreover, a side by side comparative analysis with the RN6(1–45) derived peptide highlights that the antimicrobial activity is mostly retained at the protein N-terminus. Further work by site directed mutagenesis and structural analysis has identified two residues involved in the protein antimicrobial action (Trp1 and Ile13) that are essential for the Cell Agglutination properties. This is the first structure-functional characterization of RNase6 antimicrobial properties, supporting its contribution to the infection focus clearance.
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protein post translational modification in host defense the antimicrobial mechanism of action of human eosinophil cationic protein native forms
2014Co-Authors: Vivian A Salazar, Jenny Rubin, Mohammed Moussaoui, David Pulido, M V Nogues, Ester BoixAbstract:Knowledge on the contribution of protein glycosylation in host defense antimicrobial peptides is still scarce. We have studied here how the post-translational modification pattern modulates the antimicrobial activity of one of the best characterized leukocyte granule proteins. The human eosinophil cationic protein (ECP), an eosinophil specific granule protein secreted during inflammation and infection, can target a wide variety of pathogens. Previous work in human eosinophil extracts identified several ECP native forms and glycosylation heterogeneity was found to contribute to the protein biological properties. In this study we analyze for the first time the antimicrobial activity of the distinct native proteins purified from healthy donor blood. Low and heavy molecular weight forms were tested on Escherichia coli Cell cultures and compared with the recombinant non-glycosylated protein. Further analysis on model membranes provided an insight towards an understanding of the protein behavior at the cytoplasmic membrane level. The results highlight the significant reduction in protein toxicity and bacteria Agglutination activity for heavy glycosylated fractions. Notwithstanding, the lower glycosylated fraction mostly retains the lipopolysaccharide binding affinity together with the cytoplasmic membrane depolarization and membrane leakage activities. From structural analysis we propose that heavy glycosylation interferes with the protein self-aggregation, hindering the Cell Agglutination and membrane disruption processes. The results suggest the contribution of post-translational modifications to the antimicrobial role of ECP in host defense.
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exploring new biological functions of amyloids bacteria Cell Agglutination mediated by host protein aggregation
2012Co-Authors: Marc Torrent, David Pulido, Victoria M Nogues, Ester BoixAbstract:Antimicrobial proteins and peptides (AMPs) are important effectors of the innate immune system that play a vital role in the prevention of infections. Recent advances have highlighted the similarity between AMPs and amyloid proteins. Using the Eosinophil Cationic Protein as a model, we have rationalized the structure-activity relationships between amyloid aggregation and antimicrobial activity. Our results show how protein aggregation can induce bacteria Agglutination and Cell death. Using confocal and total internal reflection fluorescence microscopy we have tracked the formation in situ of protein amyloid-like aggregates at the bacteria surface and on membrane models. In both cases, fibrillar aggregates able to bind to amyloid diagnostic dyes were detected. Additionally, a single point mutation (Ile13 to Ala) can suppress the protein amyloid behavior, abolishing the agglutinating activity and impairing the antimicrobial action. The mutant is also defective in triggering both leakage and lipid vesicle aggregation. We conclude that ECP aggregation at the bacterial surface is essential for its cytotoxicity. Hence, we propose here a new prospective biological function for amyloid-like aggregates with potential biological relevance.
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antimicrobial action and Cell Agglutination by the eosinophil cationic protein are modulated by the Cell wall lipopolysaccharide structure
2012Co-Authors: David Pulido, Mohammed Moussaoui, Marc Torrent, David Andreu, Victoria M Nogues, Ester BoixAbstract:Antimicrobial proteins and peptides (AMPs) are essential effectors of innate immunity, acting as a first line of defense against bacterial infections. Many AMPs exhibit high affinity for Cell wall structures such as lipopolysaccharide (LPS), a potent endotoxin able to induce sepsis. Hence, understanding how AMPs can interact with and neutralize LPS endotoxin is of special relevance for human health. Eosinophil cationic protein (ECP) is an eosinophil secreted protein with high activity against both Gram-negative and Gram-positive bacteria. ECP has a remarkable affinity for LPS and a distinctive agglutinating activity. By using a battery of LPS-truncated E. coli mutant strains, we demonstrate that the polysaccharide moiety of LPS is essential for ECP-mediated bacterial Agglutination, thereby modulating its antimicrobial action. The mechanism of action of ECP at the bacterial surface is drastically affected by the LPS structure and in particular by its polysaccharide moiety. We have also analyzed an N-terminal fragment that retains the whole protein activity and displays similar Cell Agglutination behavior. Conversely, a fragment with further minimization of the antimicrobial domain, though retaining the antimicrobial capacity, significantly loses its agglutinating activity, exhibiting a different mechanism of action which is not dependent on the LPS composition. The results highlight the correlation between the protein's antimicrobial activity and its ability to interact with the LPS outer layer and promote bacterial Agglutination.
Weeshian Chan - One of the best experts on this subject based on the ideXlab platform.
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2008Co-Authors: Weeshian Chan, Sanjeev Chunilal, Agnes Y Y Lee, Mark Crowther, Jeffrey S GinsbergAbstract:Along with compression ultrasonography of the legs, widely viewed as the preferred test for diagnosing deep venous thrombosis (DVT), D-dimer testing frequently is carried out because it is highly sensitive and a negative result may preclude the need for further testing. The latter test has, however, not been evaluated for diagnosing DVT in pregnancy because of its relatively low specificity. This study sought to determine the utility of the easily performed SimpliRED assay for diagnosing DVT in pregnant women. A prospective cohort study, conducted at university-affiliated Canadian hospitals, enrolled 149 consecutive pregnant women suspected of having DVT. They underwent compression ultrasonography on days 0, 3, and 7, and were followed up clinically after 3 months to determine the presence or absence of DVT. Whole blood samples were obtained at initial presentation for the SimpliRED assay. In this rapid test, blood is mixed with a conjugate of monoclonal antibody to D-dimer linked to a monoclonal antibody that binds to the red Cell surface. High levels of D-dimer cause Agglutination. DVT was diagnosed in 13 of the 149 participants (8.7%). All cases but one were diagnosed from initial compression ultrasonography. The SimpliRED assay was 100% sensitive and 60% specific, and had a negative predictive value of 100%. When stratifying the results of D-dimer testing by the presence or absence of patient risk factors, women having positive D-dimer test results in the first trimester of pregnancy had a high prevalence of DVT (62.5%) regardless of whether or not risk factors were present. Among pregnant women in whom DVT was not diagnosed, the assay was positive in no women in the first trimester, 24% of second-trimester pregnancies, and 51% of women in the third trimester. These findings indicate that the SimpliRED D-dimer assay is clinically useful in pregnant women suspected of having DVT. A negative result effectively excludes this diagnosis. The test appears to be useful for at least the first 2 trimesters of pregnancy.
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2007Co-Authors: Weeshian Chan, Sanjeev Chunilal, Mark Crowther, Marc A Rodger, Jeffrey S GinsbergAbstract:Because D-dimer levels increase in pregnancy, it was thought that D-dimer testing is less accurate for diagnosing venous thromboembolism in pregnant women than in nonpregnant women. In this observa...
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a red blood Cell Agglutination d dimer test to exclude deep venous thrombosis in pregnancy
2007Co-Authors: Weeshian Chan, Sanjeev Chunilal, Mark A Crowther, Marc Rodger, Jeffrey S GinsbergAbstract:Background: D-Dimer testing is often used with compression ultrasonography for the diagnosis of deep venous thrombosis (DVT) in nonpregnant patients. The D-dimer test is highly sensitive, and a negative result can obviate the need for further testing for DVT. This test has not been studied for DVT diagnosis in pregnancy because its specificity was deemed too poor. Objective: To determine the sensitivity and specificity and assess the utility of the SimpliRED assay (Agen Biomedical, Brisbane, Australia) for the diagnosis of DVT in pregnant women. Design: Prospective cohort study. Setting: 5 tertiary university-affiliated Canadian hospitals providing care to obstetric patients. Patients: 149 consecutive pregnant women with suspected DVT who presented to 1 of the participating centers over 5 years. Intervention: Participating women were tested with compression leg ultrasonography (single or serially on days 0, 3, and 7) and received 3 months' clinical follow-up for the presence or absence of DVT. Whole blood was tested with the SimpliRED assay at initial presentation, and results were correlated with ultrasonography and clinical findings for the presence or absence of DVT. Measurements: The sensitivity, specificity, and negative predictive value of the SimpliRED assay were calculated, along with the prevalence of false-positive SimpliRED assay results (with 95% Cls). Results: The prevalence of DVT in the cohort was 8.7% (95% Cl, 5.2% to 14.4%). The sensitivity of the SimpliRED assay was 100% (Cl, 77% to 100% [13 of 13 patients]), the specificity was 60% (Cl, 52% to 68% [81 of 135]), and the negative predictive value was 100% (Cl, 95% to 100% [81 of 81]). The SimpliRED assay was positive in 0% (Cl, 0% to 60%), 24% (Cl, 14% to 37%), and 51% (Cl, 40% to 61%) of women in the first, second, and third trimesters, respectively, among pregnant patients in whom DVT was not diagnosed. Limitations: The prevalence of DVT in the cohort was low, resulting in wide Cls. The clinician's previous impression was used to determine pretest probability in the absence of a validated clinical prediction rule for pregnant women. Conclusion: The SimpliRED assay may be useful in pregnancy because a normal result excludes DVT and occurs frequently enough to be clinically helpful.