scholarly journals The D-Dimer Test for Deep Venous Thrombosis: Gold Standards and Bias in Negative Predictive Value

2003 ◽  
Vol 49 (4) ◽  
pp. 570-574 ◽  
Author(s):  
John T Philbrick ◽  
Steven Heim
Keyword(s):  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Gold Standard ◽  
English Language ◽  
False Negative ◽  
True Negative ◽  
Language Studies ◽  
D Dimer

Abstract Background: Because venous ultrasound (US) fails to fully image the calf veins, there is the potential for US gold standard studies to classify patients with calf deep venous thrombosis (DVT) in the nondiseased category, causing bias in test index calculations. A false increase in negative predictive value (NPV) is especially likely because calf DVT false-negative tests will be counted in the numerator along with the true-negative tests in NPV calculations. We verified the presence and magnitude of this bias for the d-dimer test. Methods: We abstracted data on overall (calf and thigh) and thigh-only test sensitivity, specificity, and NPV from the six English language studies published between March 1995 and October 2001 that compared d-dimer to a gold standard (GS) capable of imaging both thigh and calf veins and that also stratified results by thigh and calf location. Thigh specificity and NPV were calculated classifying calf DVT patients as free of disease. Results: The six studies included 81–214 participants and provided 26 comparisons of 16 different d-dimer assays to the GS. Thigh sensitivity was higher than overall sensitivity in 22 of 26 comparisons (range, −0.3 to 8.6); thigh specificity was lower than overall specificity in all comparisons (range, −0.7 to −7.8); and thigh NPV was higher than overall NPV in 22 of 26 comparisons and unchanged in 4 comparisons (range, 0.0–9.2). NPV was >95% in 20 of the thigh results but >95% in only 8 of the overall results. Conclusions: Different GS can produce clinically significant differences in test indices. Care must be taken in interpreting DVT studies that evaluate d-dimer as a rule-out test and that use US as a GS, because missed calf DVT can falsely increase the NPV.

scholarly journals The Diagnostic Efficacy of Age-Adjusted D-Dimer Cutoff Value and Pretest Probability Scores for Deep Venous Thrombosis

2019 ◽  
Vol 25 ◽  
pp. 107602961982631 ◽  
Author(s):  
Junxun Li ◽  
Fan Zhang ◽  
Chujia Liang ◽  
Zhuangjian Ye ◽  
Shaoqian Chen ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Diagnostic Efficacy ◽  
Predictive Values ◽  
Cutoff Value ◽  
Wells Score ◽  
D Dimer

This study seeks to evaluate the diagnostic value of D-Dimer Plus and Innovance D-Dimer as well as the age-adjusted cutoff value for D-dimer detection in combination with 4 pretest probability (PTP) scores for deep venous thrombosis (DVT). A total of 688 patients referred for lower extremity vascular compression venous ultrasonography for suspected DVT from January 2016 to May 2018 in the First Affiliated Hospital of Sun Yat-sen University underwent D-dimer tests combining with 4 PTP scores. The diagnostic efficacy of the Wells score was the highest of the 4 PTP scores. The diagnostic efficacy of Innovance D-Dimer for DVT was greater than that of D-Dimer Plus, with better sensitivity and negative predictive value, which were both greater than 98%. If the cutoff values were adjusted by age, the Innovation D-Dimer could further improve both the specificity and the positive predictive value, providing better diagnostic performance. When the 2 D-dimer detections were used in combination with 4 PTP scores for DVT diagnosis, separately, both the positive predictive value and the negative predictive value significantly improved for D-Dimer Plus, and the positive predictive values significantly improved for Innovance D-Dimer. However, the sensitivity, specificity, and negative predictive values did not obviously change. For our patients, Wells score had the best diagnostic efficacy for our patients with suspected DVT among the 4 PTP scores. Innovance D-Dimer in combination with age-adjusted cutoff values exhibited increased sensitivity and negative predictive value for DVT diagnosis and was equivalent to the diagnostic efficacy of the Innovance D-Dimer in combination with PTP scores.

scholarly journals Reliability of Five Rapid D-Dimer Assays Compared to ELISA in the Exclusion of Deep Venous Thrombosis

1997 ◽  
Vol 77 (02) ◽  
pp. 262-266 ◽  
Author(s):  
M C H Janssen ◽  
A E Heebels ◽  
M de Metz ◽  
H Verbruggen ◽  
H Wollersheim ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Negative Predictive Value ◽  
Degradation Product ◽  
Predictive Value ◽  
Clinical Management ◽  
Screening Test ◽  
Latex Agglutination ◽  
Fibrin Degradation Product ◽  
D Dimer

SummaryStudies measuring the fibrin degradation product D-Dimer (DD) using enzyme-linked immunosorbent assays (ELISA) in patients with venographically proven deep venous thrombosis (DVT) suggest that it is possible to exclude DVT when DD level is below a certain cut-off level. However, ELISA methods are time-consuming and not available in all laboratories. Different rapid latex-agglutination assays have been investigated, but their sensitivity is considerably lower.In the present study we compared the value of four novel latex DD tests (Tinaquant®, Minutex®, Ortho® and SimpliRed®) and one rapid ELISA (VIDAS®) to a classical ELISA DD assay (Organon Mab Y18®) in 132 patients suspected of DVT.The VIDAS®, a new quantitative automated ELISA, had a sensitivity of 100% and a negative predictive value of 100% for both proximal and distal DVT at a cut-off level of 500 ng/ml. The Tinaquant® assay, a new quantitative latex method, had a sensitivity of 99% and a negative predictive value of 93% for both proximal and distal DVT at a cut-off level of 500 ng/ml. For proximal DVT only, both assays had a sensitivity and negative predictive value of 100%. VIDAS® and Tinaquant® correlated well with ELISA (correlation of r = 0.96 and r = 0.98 respectively). Sensitivities of the semi-quantitative latex assays Minutex®, Ortho® and SimpliRed® were considerably lower (77%, 51 % and 61 % respectively).These results suggest that VIDAS® and Tinaquant® may be used instead of ELISA DD in the exclusion of DVT. Tinaquant® can be performed within 20 min and VIDAS® within 35 min. Both assays might be used as a routine screening test and should be evaluated in large clinical management studies.

scholarly journals LO06: Role of the age adjusted D-dimer in suspected deep venous thrombosis

CJEM ◽  
2017 ◽  
Vol 19 (S1) ◽  
pp. S29
Author(s):  
P. Reardon ◽  
S. Patrick ◽  
M. Taljaard ◽  
K. Thavorn ◽  
M.A. Mukarram ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Older Patients ◽  
Large Scale ◽  
False Negative ◽  
Cost Savings ◽  
Low Risk ◽  
Clinical Probability ◽  
D Dimer

Introduction: It is well established that a negative D-dimer will reliably rule out thromboembolism in selected low risk patients. Multiple modified D-dimer cutoffs have been suggested for older patients to improve diagnostic specificity. However, these approaches are better established for pulmonary embolism than for deep venous thrombosis (DVT). This study will evaluate the diagnostic performance of previously suggested D-dimer cutoffs for low risk DVT patients in the ED, and assess for a novel cutoff with improved performance. Methods: This health records review included patients >50 years with suspected DVT who were low-risk and had a D-dimer performed. Our analysis evaluated the diagnostic accuracy of D-dimer cutoffs of 500 and the age adjusted (age x 10) rule for patients >50 years; and 750, and 1,000 cutoffs for patients >60 years. 30-day outcome was a diagnosis of DVT. We also assessed the diagnostic accuracy for a novel cutoff (age x 12.5). Results: 1,000 patients (mean age 68 years; 59% female) were included. Of these, 110 patients (11%) were diagnosed with DVT. The conventional cutoff of <500 µg/L demonstrated a sensitivity of 99.1% (95% CI 95.0-99.9) and a specificity of 36.4% (95% CI 33.2-39.7). For patients >60 years, the absolute cutoffs of 750 and 1,000 showed sensitivity of 98.7% (95% CI, 92.9, 99.9), and the specificity increased to 48.6% (95% CI, 44.5-52.8%) and 62.1% (95% CI, 58.1-66.1%) respectively. For all study patients, age adjusted D-dimer demonstrated a sensitivity of 99.1% (95% CI 95.0-99.9) and a specificity of 51.2% (95% CI, 47.9-54.6). A novel age adjusted cutoff (age x 12.5) for patients >50, demonstrated a sensitivity of 97.3% (95% CI 92.2-99.4) and a specificity of 61.2% (95% CI 58.0-64.5). When compared to conventional cutoff, the age adjusted cutoffs (age x 10 and age x 12.5) would have resulted in an absolute decrease in further investigations of 13.1% and 22.2%, respectively, with false negative rates of 0.1% and 0.3%. Conclusion: Among older patients with suspected DVT and low clinical probability, the age adjusted D-dimer increases the proportion of patients among whom DVT can be ruled out. A novel cutoff (age x 12.5) demonstrated improved specificity. Future large scale prospective studies are needed to confirm this finding and to explore the cost savings of these approaches.

scholarly journals DIAGNOSTIC ACCURACY OF 99 MTC LABELLED UBIQUICIDIN (29-41) SPECT/CT FOR DIAGNOSIS OF OSTEOMYELITIS IN DIABETIC FOOT

2021 ◽  
Vol 71 (3) ◽  
pp. 1015-19
Author(s):  
Muhammad Atif ◽  
Fida Hussain ◽  
Zaigham Salim Dar ◽  
Jameela Khatoon ◽  
Saadia Ajmal ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Diabetic Foot ◽  
Predictive Value ◽  
Gold Standard ◽  
Soft Tissues ◽  
Bone Biopsy ◽  
False Negative ◽  
Armed Forces ◽  
True Negative ◽  
Cross Sectional

Objective: To determine diagnostic accuracy of 99mTc labelled Ubiquicidin (29-41) SPECT/CT for detection of osteomyelitis in diabetic foot patients by taking bone biopsy as gold standard. Study Design: Cross-sectional validation study. Place and Duration of Study: Nuclear Medical Centre, Armed Forces Institute of Pathology, from Apr 2017 to Mar 2018. Methodology: Study assessed 122 patients of both genders, aged between 30-80 years (mean age=55.3 years), presenting with diabetic foot ulcers having suspicion of osteomyelitis, by 99mTc-Ubiquicidin (29-41) SPECT/CT followed by bone biopsy (histopathology and culture) taken as gold standard. Results: Among 122 patients [94 male (77%) and 28 female (23%)], osteomyelitis was histopathologically confirmed in 113 patients. 107 out of these patients were positive for osteomyelitis on 99mTc-UBI (29-41) SPECT/CT (true positives) while 6 were false negative. Out of 9 patients declared negative for osteomyelitis on histopathology and culture, 8 were negative on 99mTc-UBI (29-41) SPECT/CT as well (true negative) while only 1 case came out to be positive (false positive). Thus, the 99mTc-UBI (29-41) scan showed 94.6% sensitivity, 88.89% specificity, 99% positive predictive value, 57% negative predictive value with overall 94.2% diagnostic accuracy. Conclusion: 99mTc labelled Ubiquicidin (29-41) SPECT/CT scan can precisely localize infective focus, in diabetic foot osteomyelitis, with simultaneous discrimination between bone and soft tissues.

scholarly journals To determine the diagnostic accuracy of aspartate aminotransferase to platelet ratio index in detecting significant fibrosis in chronic hepatitis C patients by using histopathology as gold standard.

2021 ◽  
Vol 28 (08) ◽  
pp. 1166-1171
Author(s):  
Mahwish Yasin ◽  
◽  
Huma Muzaffar ◽  
M Ahmed Zamir ◽  
Talha Munir ◽  
...  
Keyword(s):  
Chronic Hepatitis ◽  
Hepatitis C ◽  
Diagnostic Accuracy ◽  
Chronic Hepatitis C ◽  
Predictive Value ◽  
Gold Standard ◽  
False Negative ◽  
True Negative ◽  
Significant Fibrosis ◽  
Chronic Hepatitis C Patients

Objective: The objective of the study was to: determine the diagnostic accuracy of AST to platelet ratio index in detecting significant fibrosis in chronic hepatitis C patients by using histopathology as gold standard. Study Design: Cross Sectional study. Settings: Department of Medicine, DHQ Hospital, Faisalabad. Period: 1st Oct 2017 to March 2018. Results: In this study, out of 158 cases, 48.73%(n=77) were between 25-40 years while 51.27%(n=81) were between 41-60 years, mean+SD was calculated as 40.94+9.10 years, 55.06%(n=87) were male and 44.94%(n=71) were females, mean AST and platelet count was calculated as 1.68+0.54 and 191.0+43.75, frequency of significant fibroids in chronic hepatitis C patients by using histopathology as gold standard reveals as 53.16%(n=84) while 46.84%(n=74) had no findings of this morbidity. The diagnostic accuracy of AST to platelet ratio index in detecting significant fibrosis in chronic hepatitis C patients by using histopathology as gold standard was recorded which shows 51.27%(n=81) as true positive, 2.53%(n=4) false positive, 1.89%(n=3) false negative and 44.31%(n=70) were recorded as true negative, sensitivity, specificity, positive predictive value, negative predictive value and accuracy rate was computed as 96.43%, 94.59%, 95.29%, 95.89% and 95.57% respectively. Conclusion: The results of the study reveal that diagnostic accuracy of AST to platelet ratio for detection of significant fibrosis in chronic Hepatitis C patients was satisfactory and it may be used for the avoidance of invasive liver biopsy to initiate the antiviral therapy in these patients.

Diagnostic Value of a New Sensitive Membrane Based Technique for Instantaneous D-Dimer Evaluation in Patients with Clinically Suspected Deep Venous Thrombosis

1997 ◽  
Vol 77 (04) ◽  
pp. 637-640 ◽  
Author(s):  
Christophe Leroyer ◽  
Martine Escoffre ◽  
Emmanuelle Le Moigne ◽  
Marc Grimaux ◽  
Olivier Cagnioncle ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Predictive Value ◽  
Clinical Signs ◽  
High Sensitivity ◽  
Diagnostic Value ◽  
Lower Sensitivity ◽  
Predictive Values ◽  
Study Results ◽  
D Dimer

SummaryBackground: Plasma D-Dimer analysis, using ELISA assays, has demonstrated in previous studies a high sensitivity, suggesting its utility in excluding deep venous thrombosis (DVT). Aim: To assess the performance of a new rapid plasma D-Dimer ELISA measurement in suspected DVT patients with recent clinical signs, not exceeding one week. Methods: A prospective study of patients admitted for a suspected recent DVT. Contrast venography or compression ultrasonography were performed within 24 h of admission. A new membrane based ELISA technique, which uses an immunofiltration and two complementary monoclonal antibodies was tested. Results were expressed as positive or negative. A standard plasma D-Dimer ELISA measurement was also performed. D-Dimer performances were assessed at the end of the study. Results: 265/448 patients had a proven DVT (72 distal, 193 proximal). The sensitivity of the instantaneous method in the diagnosis of overall DVT is 92 ± 3.4% (95% Cl), and specificity is 36.6 ± 6.9%. Positive predictive value is 67.7 ± 4.8% and negative predictive value is 76.1 ± 8.9%. Sensitivity and negative predictive values reach 97.9 and 94.3% in the diagnosis of proximal DVT, but only 76.3 and 79.7% in the diagnosis of distal DVT. Similar results are observed with the standard ELISA method. Conclusion: This new rapid plasma D-Dimer measurement appears highly sensitive, and could substitute the older ELISA methods. Both methods provide lower sensitivity in the case of a distal DVT location.

D-dimer Strategy in Thrombosis Exclusion

1998 ◽  
Vol 79 (01) ◽  
pp. 32-37 ◽  
Author(s):  
H. Trillaud ◽  
S. Labrouche ◽  
P. Gauthier ◽  
S. Javorschi ◽  
P. Bernard ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Gold Standard ◽  
Quantitative Methods ◽  
Rapid Methods ◽  
Radiologic Examination ◽  
The Cost ◽  
D Dimer

SummaryDD are now recognized as a valuable tool to screen patients suspected of deep venous thrombosis or pulmonary embolism before carrying out a gold standard radiologic examination. The newest methods available claim to be able to ascertain the absence of thrombosis, but they have yet to prove their efficiency. We compared the performances of 3 reference ELISA methods (D-DI Asserachrom™ Stago, D-dimer Enzygnost™ Behring and Dimertest GOLD EIA™ Agen), 5 recent rapid methods (VIDAS D-Dimer™ bioMérieux, Instant IA™ Stago, Simplired™ Agen, Nycocard D-dimer™ Nycomed and Accuclot D-Dimer™ Sigma Diagnostics) and two routine latex methods (Dimertest™ American Diagnostica and FDP-Slidex™ bioMérieux) in 100 patients. One of the rapid quantitative methods was demonstrated to have a level of efficiency comparable to that of ELISA methods. Finally, the cost and efficiency of different strategies were evaluated, the association of a routine latex method with the VIDAS D-Dimer™ bioMérieux being proven to be the most efficient.

scholarly journals Sensitivity and Specificity of Gene Xpert in the Diagnosis of Spinal Tuberculosis: A Prospective Controlled Clinical Study

2019 ◽  
Vol 10 (5) ◽  
pp. 553-558
Author(s):  
Anil M. Solanki ◽  
Saumyajit Basu ◽  
Amitava Biswas ◽  
Subhendu Roy ◽  
Aditya Banta
Keyword(s):  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Sensitivity And Specificity ◽  
Predictive Value ◽  
Spinal Tuberculosis ◽  
False Negative ◽  
High Sensitivity ◽  
Control Group ◽  
Surgical Biopsy ◽  
True Negative

Study Design: Prospective matched cohort study Objective: To evaluate the sensitivity and specificity of Gene Xpert in the diagnosis of spinal tuberculosis. Methods: From January 2016 to August 2018, Gene Xpert results were prospectively studied in 68 patients of clinicoradiologically suspected spinal tuberculosis (STB) and a control group (CG) of 92 patients, all of whom underwent computed tomography–guided/C-arm-guided/open surgical biopsy. Sensitivity, specificity, positive predictive value, and negative predictive value are obtained using standard equations. Results: Out of 68 cases of STB, Gene Xpert was positive in 62 (true positive: 62/68) and negative in 6 (false negative: 6/68). Gene Xpert was negative for all 92 cases of CG (true negative: 92/92, false positive 0/92). Thus, in our series, sensitivity of Gene Xpert is 91.18%, specificity is 100%, positive predictive value is 100%, and negative predictive value is 93.88%. Out of all cases of STB, 62/68 (91.18%) were Gene Xpert positive, but only 35/64 (54.69%) was acid-fast bacilli (AFB) culture positive and 53/60(88.33%) was histopathologically conclusive of TB. Also, Gene Xpert was positive in 7/7 (100%) cases of STB in which histopathology were inconclusive and 25/29 (86.21%) cases of STB in which AFB culture was negative. Conclusion: In STB, Gene Xpert clearly outperforms AFB culture and histopathology due to its high sensitivity and specificity apart from being rapid in diagnosis. Hence it is justified to diagnose spinal tuberculosis by Gene Xpert though histopathology is confirmative and AFB culture remains the gold standard.

scholarly journals GESTATIONAL DIABETES;

2013 ◽  
Vol 20 (02) ◽  
pp. 232-236
Author(s):  
SHAZIA SHAHEEN ◽  
ROBINA ALI ◽  
UZMA , AFZAL
Keyword(s):  
High Risk ◽  
Gestational Diabetes ◽  
Outcome Measures ◽  
Predictive Value ◽  
Gold Standard ◽  
False Negative ◽  
Outpatient Department ◽  
High Risk Population ◽  
True Negative ◽  
Cross Sectional

Objective: To determine the Accuracy of GCT for screening of gestational diabetes in high risk population comparing oralGlucose Tolerance Test (GTT) as gold standard. Main outcome measures: Accuracy of GCT. Study design: Cross-sectional study.Setting: The study was conducted in outpatient department of Punjab Medical College and affiliated hospitals, Faisalabad. Subjects: 207patients. Methods: High risk women from outpatient department were recruited on the basis of inclusion and exclusion criteria afterexplaining pros and cons of procedure. These women were subjected to GCT & GTT. GTT was taken as gold standard test and results ofGCT were compared with it. Main outcome measures recorded and results obtained. Results: Out of 207 women, GCT truly diagnosed 24women as having diabetes (true positive) & 175 women were found to have normal glucose metabolism (true negative). GCT failed todiagnose 5 diabetic women (false negative) & wrongly diagnosed 3 normal women as diabetics (false positive) against gold standardGTT. So GCT has diagnosed Gestational diabetes mellitus with the sensitivity of 82.7%, specificity of 98.3%, positive predictive value of88.8%, and negative predictive value of 97.2% and accuracy of 96.1%. Conclusions: GCT is a simple, easy, convenient and sensitive testthat has no limitation for time or prior fasting for gestational diabetes screening.

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