Specificity Of D-dimer Research Articles

Pulmonary Embolism Risk Assessment in Acute Isolated Distal Deep Venous Thrombosis.

The clinical risk factors and risk of developing pulmonary embolism (PE) in patients with acute isolated distal deep venous thrombosis (IDDVT) were assessed using single complete-duplex ultrasound (CDUS) imaging to reduce over-testing and over-treatment. This observational study was conducted from January 2020 to December 2022. Retrospective analysis was performed on CT pulmonary angiography (CTPA), blood coagulation markers, myocardial injury markers, blood gas analysis, and CDUS imaging of the lower extremity blood vessels of 146 patients with newly diagnosed IDDVT. Binary logistic regression was used to evaluate the relationship between these indicators and PE. After stepwise regression analysis, the predictors included in the regression model were D-dimer (DD), the sum of the thrombus length, and the maximum value of the thrombus width, with odds ratios (ORs) of 1.307 (p <0.001), 1.018 (p = 0.005), and 1.613 (p = 0.018), respectively. The combined prediction model achieved an area under the receiver operating characteristic curve (AUC) of 0.832 [95% confidence interval (CI): 0.761, 0.902]. By balancing the sensitivity and specificity of DD, combined single CDUS improves the predictive value for PE in patients with IDDVT. Key Words: Venous thrombosis, Pulmonary embolism, Ultrasonography, D-dimer, Diagnosis.

Age-adjusted versus clinical probability-adjusted D-dimer to exclude pulmonary embolism

IntroductionA low D-dimer can exclude suspected pulmonary embolism (PE) in cases with low or intermediate clinical probability of disease. Yet D-dimer is nonspecific, so many cases without PE require imaging. D-dimer's specificity is improved by increasing the threshold for a positive test with age (age × 10 ng/mL; age-adjusted D-dimer; AADD) or clinical probability of PE (1000 ng/mL if low and 500 ng/mL if intermediate clinical probability; clinical probability-adjusted D-dimer; CPADD). It is unclear which approach is preferable. ObjectivesWe report the sensitivity, specificity and negative predictive value (NPV) of AADD compared to CPADD in suspected PE. Materials and methodsA retrospective cohort of 3500 consecutive cases imaged for suspected PE at two U.S. emergency departments was assembled. We analyzed cases with low or intermediate clinical probability of PE (Revised Geneva Score) who had a D-dimer. The outcome was acute PE on imaging at presentation. ResultsOf the 3500 cases, 1745 were eligible. 37% were low, and 63% were intermediate clinical probability of PE. PE was present in 145 (8.3%) cases. Sensitivity of CPADD was 87.5% vs. 96.6% for AADD (difference 9.1%; 95% CI 4.3% to 14.0%). NPV of CPADD was 97.1% vs. 99.0% for AADD (difference 1.9%; 95% CI, 0.7% to 3.1%). Specificity of CPADD was 37.5% vs. 30.2% for AADD (difference –7.3%; 95% CI –9.4% to –5.1%). D-dimer was negative in 35.4% of cases using CPADD vs. 28.0% using AADD. ConclusionsCPADD modestly improved the specificity of D-dimer, but had a lower NPV than AADD. AADD appears preferable in this analysis.

D-dimer as an indicator of dengue severity

Background: Dengue infection is a problem of global concern. The clinical spectrum of the disease varies from an acute febrile course accompanied by mild hemorrhagic manifestations with uneventful recovery to refractory shock and massive bleeding with high mortality. Several mechanisms may be involved in the pathogenesis of bleeding, namely: vasculopathy, thrombocytopenia, coagulopathy and dissiminated intravascular coagulopathy (DIC). Objective: To determine the relationship between D-dimer (DD) levels and clinical outcome in dengue patients. Method: Children with suspected dengue infection admitted to King Chulalongkorn Memorial Hospital were enrolled. D-dimer (DD) was sequentially measured during the course of illness using whole blood and a rapid semiquantitative system (SimpliRed). Diagnosis of dengue infection was confirmed by serology and WHO criteria were used for classifying dengue severity. Results: 41 dengue patients, 22 girls and 19 boys were recruited in the study. The mean age was 9.68 years. There were 12 (29.3 %) cases of dengue fever (DF) and 29 (70.7 %) cases of dengue hemorrhagic fever (DHF). DD was more significantly present in the DHF group (87 %) than in the DF group (13%) (P<0.03). The sensitivity and specificity of DD in predicting severe dengue infection (DHF) were 90% and 67 %, respectively. Sequential analysis of DD showed higher levels at all stages of dengue infection. It correlated with the disease severity. Conclusion: Semiquantitative DD assay measurements in children suffering from dengue infection significantly correlated with dengue severity.

D‐Dimer test in cancer patients with suspected acute pulmonary embolism

The safety of a D-dimer (DD) measurement in cancer patients with clinically suspected pulmonary embolism (PE) is unclear. The aim of this study was to assess the accuracy of the DD test in consecutive patients with clinically suspected PE with and without cancer. The diagnostic accuracy of DD (Tinaquant D-dimer) was first retrospectively assessed in an unselected group of patients referred for suspected PE (n = 350). Subsequently, the predictive value of the DD was validated in a group of consecutive inpatients and outpatients with clinically suspected PE prospectively enrolled in a management study (n = 519). The results of the DD test in cancer patients were assessed according to the final diagnosis of PE and the 3-month clinical follow-up. In the first study group, DD showed a sensitivity and a negative predictive value (NPV) of 100% and 100% in patients with cancer and 97% and 98% in those without malignancy, respectively. In the validation cohort, the sensitivity and NPV of DD were both 100% (95% CI 82%-100% and 72%-100%, respectively), whereas in patients without malignancy, the corresponding estimates were 93% (95% CI 87%-98%) and 97% (95% CI, 95%-99%), respectively. The specificity of DD was low in patients with (21%) and without cancer (53%). A negative DD result safely excludes the diagnosis of PE in patients with cancer. Because of the low specificity, when testing 100 patients with suspected PE, a normal DD concentration safely excludes PE in 15 patients with cancer and in 43 patients without cancer.

The Use of a Clinical Prediction Model and D-Dimer (DD) Testing in the Diagnosis of Deep Vein Thrombosis (DVT): A Systematic Review.

Background: The diagnosis of DVT can be made by determining pretest probability of disease and using this information in combination with DD testing and ultrasound imaging. A number of studies have evaluated the use of clinical probability but this literature has not been summarized.Purpose: To systematically review trials that evaluated DVT prevalence using clinical prediction rules either with or without DD for the diagnosis of DVT.Data Sources: English and French language studies were identified from a MEDLINE search from 1990 to March 2004 and were supplemented by a review of all relevant bibliographies.Study Selection: Prospective management studies of symptomatic outpatients with suspected DVT in which patients were followed for a minimum of 3 months were selected. Clinical prediction rules had to be employed prior to DD and diagnostic tests. Studies were excluded if patients with a history of prior DVT were enrolled or if insufficient information was presented to calculate the prevalence of DVT for each of the 3 clinical probability estimates (low, moderate and high risk).Data Extraction: Two reviewers assessed each study for inclusion/exclusion criteria and collected data on prevalence and on sensitivity, specificity and likelihood ratios of DD in each of the 3 clinical probability estimates (low, moderate and high risk).Data Synthesis: 14 management studies involving a clinical prediction model in the diagnosis of DVT in over 8000 patients were included, of which 11 utilized DD in the diagnostic algorithm. All studies employed the same clinical prediction rule. The inverse variance weighted average prevalence of DVT in the low, moderate and high probability subgroups were 4.9% (95% CI= 4.2% to 5.7%), 17.4% (95% CI= 16.2% to 18.8%), and 53.6% (95% CI= 51.1% to 56.2%), respectively. The overall weighted prevalence was 18.3% (95% CI= 17.4% to 19.2%). The sensitivity of DD for the diagnosis of DVT in the low, moderate and high probability subgroups were 90.4% (95% CI= 84.7% to 94.2%), 92.0 % (95% CI= 89.1% to 94.2%), 93.6% (95% CI= 91.2% to 94.3%); and the specificities were 69.9% (95% CI= 68.0% to 71.8%), 52.4% (95% CI= 49.8% to 55.0%), and 43.2% (95% CI= 38.8% to 47.6%), respectively. The Mantel-Haenszel pooled estimates for diagnostic odds ratios (DOR) were 17.4 (95%CI=10.4–29.1), 10.2 (95% CI=7.1–14.6), and 10.1 (95% CI=6.9–14.9) in low, moderate and high groups respectively.Conclusion: Accurate estimates of the prevalence of DVT can be achieved using the same clinical prediction rule. Using this rule, it is unlikely that low probability patients have a DVT probability of more than 5%. Specificity of the DD seems to have clinically relevant differences depending on pretest probability but the DORs (which incorporate sensitivity and specificity) are similar. The data suggest that DVT can be excluded if patients are low probability even when DDs of lower sensitivity are employed and that DD testing has lower utility in high probability patients since false positives are common.

Contribution of noninvasive evaluation to the diagnosis of pulmonary embolism in hospitalized patients

The effectiveness of new diagnostic tools for suspected pulmonary embolism (PE), such as clinical probability assessment, plasma D-dimer (DD) measurement and lower limb venous compression ultrasonography (US), has not been specifically studied in patients with a suspected PE occurring during hospital stay. This study applied a sequential, decision analysis-based strategy adding these instruments to a ventilation/perfusion lung scan in a cohort of 114 consecutive inpatients clinically suspected of PE in order to establish in how many patients a pulmonary angiogram could thereby be avoided. A definitive diagnosis could be established by the noninvasive protocol in 61% of these patients: normal/near-normal lung scan, 14%; high probability lung scan, 19%; clinical probability combined with lung scan result, 18%; and US, 8%. Specificity of DD was only 7% and contributed to the exclusion of PE in only two patients. Pulmonary angiography was required in 39% of patients. The 3-month thromboembolic risk in patients in whom PE was excluded by the diagnostic process was 0% (95% confidence interval 0-4.9%). In conclusion, a noninvasive work-up for suspected pulmonary embolism is effective in hospitalized patients, allowing to forego angiography in 61% of them, and it appears to be safe, although this should be further investigated. In contrast to outpatients, D-dimer measurement appears to be useless in hospitalized patients.

P38 Mitogen-activated protein kinase regulates IL-8 expression in human pulmonary vascular endothelial cells

The effectiveness of new diagnostic tools for suspected pulmonary embolism (PE), such as clinical probability assessment, plasma D-dimer (DD) measurement and lower limb venous compression ultrasonography (US), has not been specifically studied in patients with a suspected PE occurring during hospital stay. This study applied a sequential, decision analysis-based strategy adding these instruments to a ventilation/perfusion lung scan in a cohort of 114 consecutive inpatients clinically suspected of PE in order to establish in how many patients a pulmonary angiogram could thereby be avoided. A definitive diagnosis could be established by the noninvasive protocol in 61% of these patients: normal/near-normal lung scan, 14%; high probability lung scan, 19%; clinical probability combined with lung scan result, 18%; and US, 8%. Specificity of DD was only 7% and contributed to the exclusion of PE in only two patients. Pulmonary angiography was required in 39% of patients. The 3-month thromboembolic risk in patients in whom PE was excluded by the diagnostic process was 0% (95% confidence interval 0-4.9%). In conclusion, a noninvasive work-up for suspected pulmonary embolism is effective in hospitalized patients, allowing to forego angiography in 61% of them, and it appears to be safe, although this should be further investigated. In contrast to outpatients, D-dimer measurement appears to be useless in hospitalized patients.