Harmonized D-dimer levels upon admission for prognosis of COVID-19 severity: Results from a Spanish multicenter registry (BIOCOVID-Spain study)

D-dimer-An International Assessment of the Quality of Laboratory Testing: Implications for D-dimer Use in the Real World

D-dimer assessment has several established roles in venous thromboembolism (VTE) and disseminated intravascular coagulation diagnosis, and recently the risk stratification of coronavirus disease 2019 (COVID-19). D-dimer assays are neither standardized nor harmonized, use varying methodologies, and use different reporting units, all resulting in a lack of interchangeability and generalizability of assays. Using large multiyear datasets from an international laboratory quality assurance program, we assessed (1) common D-dimer assays in use worldwide, (2) differences in analytical performance between different methods, and (3) interlaboratory variability between positive samples. External proficiency testing results from laboratories participating in the External Quality Control for Assays and Tests (ECAT) Foundation were analyzed from 2017 to 2023. Annually, between 578 and 690 laboratories participated in the D-dimer sample surveys with response rates ranging from 88 to 97%. The three most common assays in use in 2023 were the Siemens Innovance D-dimer (42%), the IL HemosIL D-dimer HS 500 (20%), and the Diagnostica Stago (Stago) Liatest D-dimer Plus (10%)-all these are automated, quantitative, latex immunoassays expressed in fibrinogen equivalent units (FEU). The highest interlaboratory variability was observed around the typical VTE exclusion threshold of 0.5 mg/L FEU. Lower interlaboratory variability was observed at values above 0.8 mg/L FEU. Our study provides recent, international performance data on currently used D-dimer assays and describes the significant variability between assays and across D-dimer concentrations. We demonstrate that assays are not interchangeable and that using them interchangeably has the potential to result in clinically important errors. There is an urgent need to educate users about these issues and to work towards harmonizing D-dimer units and reporting.

The performance of quantitative D-dimer assays in Chinese clinical laboratories by analyzing data from National External quality Assessment Scheme

BACKGROUND AND AIMS

To investigate performance of D-dimer assays in China and address analytical quality issues.

MATERIALS AND METHODS

D-dimer assays data were collected from China National External Quality Assessment Scheme (China NEQAS) from 2014 to 2022. We analyzed reagents, assay results, reporting unit and cutoffs in 2022 China NEQAS. Interlaboratory coefficient variations (CVs) and influence of modified/unmodified test systems on CVs were investigated over 9 years.

RESULTS

There were 82 reagent brands in China NEQAS, but 55 reagent instructions did not indicate expression unit (DDU or FEU). Up to 7-fold of the ratio of max-to-min mean results was shown among different assays with same unit on the same sample. A prevalence of FEU (63.4%) over DDU (17.1%) was observed. Although 669 laboratories (37.9%) among 1766 laboratories used reagents without VTE exclusion claim, they also reported cutoffs. The CVs of only two assays were decreasing over years. CVs of modified test systems were higher than those of unmodified systems before improvement.

CONCLUSIONS

Expression unit should be required to label in package inserts by regulatory authority. Laboratory professionals should follow instructions for use and prefer unmodified test systems for clinical safely application. Harmonization of reporting units through collaborative efforts is the promising step.

Accuracy of routine laboratory tests to predict mortality and deterioration to severe or critical COVID-19 in people with SARS-CoV-2

BACKGROUND

Identifying patients with COVID-19 disease who will deteriorate can be useful to assess whether they should receive intensive care, or whether they can be treated in a less intensive way or through outpatient care. In clinical care, routine laboratory markers, such as C-reactive protein, are used to assess a person's health status.

OBJECTIVES

To assess the accuracy of routine blood-based laboratory tests to predict mortality and deterioration to severe or critical (from mild or moderate) COVID-19 in people with SARS-CoV-2.

SEARCH METHODS

On 25 August 2022, we searched the Cochrane COVID-19 Study Register, encompassing searches of various databases such as MEDLINE via PubMed, CENTRAL, Embase, medRxiv, and ClinicalTrials.gov. We did not apply any language restrictions.

SELECTION CRITERIA

We included studies of all designs that produced estimates of prognostic accuracy in participants who presented to outpatient services, or were admitted to general hospital wards with confirmed SARS-CoV-2 infection, and studies that were based on serum banks of samples from people. All routine blood-based laboratory tests performed during the first encounter were included. We included any reference standard used to define deterioration to severe or critical disease that was provided by the authors.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from each included study, and independently assessed the methodological quality using the Quality Assessment of Prognostic Accuracy Studies tool. As studies reported different thresholds for the same test, we used the Hierarchical Summary Receiver Operator Curve model for meta-analyses to estimate summary curves in SAS 9.4. We estimated the sensitivity at points on the SROC curves that corresponded to the median and interquartile range boundaries of specificities in the included studies. Direct and indirect comparisons were exclusively conducted for biomarkers with an estimated sensitivity and 95% CI of ≥ 50% at a specificity of ≥ 50%. The relative diagnostic odds ratio was calculated as a summary of the relative accuracy of these biomarkers.

MAIN RESULTS

We identified a total of 64 studies, including 71,170 participants, of which 8169 participants died, and 4031 participants deteriorated to severe/critical condition. The studies assessed 53 different laboratory tests. For some tests, both increases and decreases relative to the normal range were included. There was important heterogeneity between tests and their cut-off values. None of the included studies had a low risk of bias or low concern for applicability for all domains. None of the tests included in this review demonstrated high sensitivity or specificity, or both. The five tests with summary sensitivity and specificity above 50% were: C-reactive protein increase, neutrophil-to-lymphocyte ratio increase, lymphocyte count decrease, d-dimer increase, and lactate dehydrogenase increase. Inflammation For mortality, summary sensitivity of a C-reactive protein increase was 76% (95% CI 73% to 79%) at median specificity, 59% (low-certainty evidence). For deterioration, summary sensitivity was 78% (95% CI 67% to 86%) at median specificity, 72% (very low-certainty evidence). For the combined outcome of mortality or deterioration, or both, summary sensitivity was 70% (95% CI 49% to 85%) at median specificity, 60% (very low-certainty evidence). For mortality, summary sensitivity of an increase in neutrophil-to-lymphocyte ratio was 69% (95% CI 66% to 72%) at median specificity, 63% (very low-certainty evidence). For deterioration, summary sensitivity was 75% (95% CI 59% to 87%) at median specificity, 71% (very low-certainty evidence). For mortality, summary sensitivity of a decrease in lymphocyte count was 67% (95% CI 56% to 77%) at median specificity, 61% (very low-certainty evidence). For deterioration, summary sensitivity of a decrease in lymphocyte count was 69% (95% CI 60% to 76%) at median specificity, 67% (very low-certainty evidence). For the combined outcome, summary sensitivity was 83% (95% CI 67% to 92%) at median specificity, 29% (very low-certainty evidence). For mortality, summary sensitivity of a lactate dehydrogenase increase was 82% (95% CI 66% to 91%) at median specificity, 60% (very low-certainty evidence). For deterioration, summary sensitivity of a lactate dehydrogenase increase was 79% (95% CI 76% to 82%) at median specificity, 66% (low-certainty evidence). For the combined outcome, summary sensitivity was 69% (95% CI 51% to 82%) at median specificity, 62% (very low-certainty evidence). Hypercoagulability For mortality, summary sensitivity of a d-dimer increase was 70% (95% CI 64% to 76%) at median specificity of 56% (very low-certainty evidence). For deterioration, summary sensitivity was 65% (95% CI 56% to 74%) at median specificity of 63% (very low-certainty evidence). For the combined outcome, summary sensitivity was 65% (95% CI 52% to 76%) at median specificity of 54% (very low-certainty evidence). To predict mortality, neutrophil-to-lymphocyte ratio increase had higher accuracy compared to d-dimer increase (RDOR (diagnostic Odds Ratio) 2.05, 95% CI 1.30 to 3.24), C-reactive protein increase (RDOR 2.64, 95% CI 2.09 to 3.33), and lymphocyte count decrease (RDOR 2.63, 95% CI 1.55 to 4.46). D-dimer increase had higher accuracy compared to lymphocyte count decrease (RDOR 1.49, 95% CI 1.23 to 1.80), C-reactive protein increase (RDOR 1.31, 95% CI 1.03 to 1.65), and lactate dehydrogenase increase (RDOR 1.42, 95% CI 1.05 to 1.90). Additionally, lactate dehydrogenase increase had higher accuracy compared to lymphocyte count decrease (RDOR 1.30, 95% CI 1.13 to 1.49). To predict deterioration to severe disease, C-reactive protein increase had higher accuracy compared to d-dimer increase (RDOR 1.76, 95% CI 1.25 to 2.50). The neutrophil-to-lymphocyte ratio increase had higher accuracy compared to d-dimer increase (RDOR 2.77, 95% CI 1.58 to 4.84). Lastly, lymphocyte count decrease had higher accuracy compared to d-dimer increase (RDOR 2.10, 95% CI 1.44 to 3.07) and lactate dehydrogenase increase (RDOR 2.22, 95% CI 1.52 to 3.26).

AUTHORS' CONCLUSIONS

Laboratory tests, associated with hypercoagulability and hyperinflammatory response, were better at predicting severe disease and mortality in patients with SARS-CoV-2 compared to other laboratory tests. However, to safely rule out severe disease, tests should have high sensitivity (> 90%), and none of the identified laboratory tests met this criterion. In clinical practice, a more comprehensive assessment of a patient's health status is usually required by, for example, incorporating these laboratory tests into clinical prediction rules together with clinical symptoms, radiological findings, and patient's characteristics.

Diagnostic value of D-dimer in differentiating multisystem inflammatory syndrome in Children (MIS-C) from Kawasaki disease: systematic literature review and meta-analysis

Coronavirus disease 2019 (COVID-19) is frequently associated with thrombo inflammation, which can predispose to developing of life-threatening conditions in children such as the multisystem inflammatory syndrome (MIS-C) and Kawasaki disease. Because of the consistent overlap in pathogenesis and symptoms, identifying laboratory tests that may aid in the differential diagnosis of these pathologies becomes crucial. We performed an electronic search in PubMed, Web of Science and Scopus, without date or language restrictions, to identify all possible studies reporting D-dimer values in separate cohorts of children with MIS-C or Kawasaki disease. Three multicenter cohort studies were included in our analysis, totaling 487 patients (270 with MIS-C and 217 with Kawasaki disease). In this meta-analysis, significantly higher D-dimer values were found in MIS-C compared to Kawasaki disease in all three studies, yielding an SMD of 1.5 (95 % CI, 1.3-1.7) mg/L. Thus, very high D-dimer values early in the course of disease should raise the clinical suspicion of MIS-C rather than Kawasaki disease. Further studies should be planned to identify harmonized D-dimer diagnostic thresholds that may help discriminate these conditions.

Unified calibration of D-dimer can improve the uniformity of different detection systems

Background

D-dimer at a low level is important evidence for excluding the onset and progression of thrombosis. It is readily detectable and yields rapid results, although significant variability exists among different detection systems. Our study aims to enhance the consistency across various detection systems.

Methods

Twelve detection systems were included in our study. We sought to address this inconsistency by using various calibrators (two supplied by manufacturers and two comprising pooled human plasma diluted with different diluents) to standardize D-dimer measurements. We categorized the data into three groups according to D-dimer concentration levels: low (≤0.5 mg/L), medium (>0.5 mg/L - <3 mg/L), and high (≥3 mg/L). We then analyzed the data focusing on range, consistency, comparability, negative coincidence rate, and false negative rate.

Results

Calibrating with pooled human plasma led to narrower result ranges in the low and medium groups (P < 0.05). In the low group, consistency improved from weak to strong (ICC 0.4-0.7, P﹤0.05), while it remained excellent in the other groups and overall (ICC﹥0.75, P﹤0.05). The percentage of pairwise comparability increased in both the low and high groups. Additionally, there was an increase in the negative coincidence rate.

Conclusion

These findings demonstrate that uniform calibration of D-dimer can significantly enhance the consistency of results across different detection systems.

Coagulopathy and adverse outcomes in hospitalized patients with COVID-19: results from the NOR-Solidarity trial

Background

Several studies have examined parameters of increased thrombogenicity in COVID-19, but studies examining their association with long-term outcome and potential effects of antiviral agents in hospitalized patients with COVID-19 are scarce.

Objectives

To evaluate plasma levels of hemostatic proteins during hospitalization in relation to disease severity, treatment modalities, and persistent pulmonary pathology after 3 months.

Methods

In 165 patients with COVID-19 recruited into the NOR-Solidarity trial (NCT04321616) and randomized to treatment with hydroxychloroquine, remdesivir, or standard of care, we analyzed plasma levels of hemostatic proteins during the first 10 days of hospitalization (n = 160) and at 3 months of follow-up (n = 100) by enzyme immunoassay.

Results

Our main findings were as follows: (i) tissue plasminogen activator (tPA) and tissue factor pathway inhibitor (TFPI) were increased in patients with severe disease (ie, the combined endpoint of respiratory failure [Po2-to-FiO2 ratio, <26.6 kPa] or need for treatment at an intensive care unit) during hospitalization. Compared to patients without severe disease, tPA levels were a median of 42% (P < .001), 29% (P = .002), and 36% (P = .015) higher at baseline, 3 to 5 days, and 7 to 10 days, respectively. For TFPI, median levels were 37% (P = .003), 25% (P < .001), and 10% (P = .13) higher in patients with severe disease at these time points, respectively. No changes in thrombin-antithrombin complex; alpha 2-antiplasmin; a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13; or antithrombin were observed in relation to severe disease. (ii) Patients treated with remdesivir had lower levels of TFPI than those in patients treated with standard of care alone. (iii) TFPI levels during hospitalization, but not at 3 months of follow-up, were higher in those with persistent pathology on chest computed tomography imaging 3 months after hospital admission than in those without such pathology. No consistent changes in thrombin-antithrombin complex, alpha 2-antiplasmin, ADAMTS-13, tPA, or antithrombin were observed in relation to pulmonary pathology at 3 months of follow-up.

Conclusion

TFPI and tPA are associated with severe disease in hospitalized patients with COVID-19. For TFPI, high levels measured during the first 10 days of hospitalization were also associated with persistent pulmonary pathology even 3 months after hospital admittance.

D-dimer diagnostics: can I use any D-dimer assay? Bridging the knowledge-to-action gap

A State of the Art lecture titled "D-dimer Diagnostics: Can I use any D-dimer assay? Bridging the Knowledge-to-Action gap" was presented at the International Society on Thrombosis and Haemostasis Congress in 2023, included in the session on the clinical impact of variability in commonly used coagulation assays. Here, we review the role of D-dimer, primarily in the outpatient diagnosis of patients with venous thromboembolism (VTE) when combined with clinical decision rules. We focus on the recent large management trials that have studied adjustments of VTE exclusion thresholds for D-dimer based on either prior clinical probability of VTE or patient age, and the resultant benefit of reduced imaging for VTE and improved diagnostic efficiency. In this context, we report on the significant variability between D-dimer results and the multiple D-dimer assays in use worldwide using data from international external quality assurance programs. This variability is particularly high at typical VTE exclusion thresholds. We discuss the potential clinical impact of D-dimer assay substitution on accuracy of diagnosis and risk stratification of patients with VTE. Finally, we summarize relevant new data on this topic presented during the 2023 International Society on Thrombosis and Haemostasis Congress and outline future priorities urgently needed to harmonize D-dimer results and reporting that will require international collaboration among multiple stakeholders with an overall goal to close this knowledge-to-action gap.

It's in the blood: a review of the hematological system in SARS-CoV-2-associated COVID-19

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an unprecedented global healthcare crisis. While SARS-CoV-2-associated COVID-19 affects primarily the respiratory system, patients with COVID-19 frequently develop extrapulmonary manifestations. Notably, changes in the hematological system, including lymphocytopenia, neutrophilia and significant abnormalities of hemostatic markers, were observed early in the pandemic. Hematological manifestations have since been recognized as important parameters in the pathophysiology of SARS-CoV-2 and in the management of patients with COVID-19. In this narrative review, we summarize the state-of-the-art regarding the hematological and hemostatic abnormalities observed in patients with SARS-CoV-2-associated COVID-19, as well as the current understanding of the hematological system in the pathophysiology of acute and chronic SARS-CoV-2-associated COVID-19.

Predictive value of inflammatory and coagulation biomarkers for venous thromboembolism in Covid-19 patients

BACKGROUND

The predictive value of coagulation markers for venous thromboembolism (VTE) in Covid-19 patients has been investigated with conflicting results.

OBJECTIVE

Our aim was to investigate the correlation between biomarkers and VTE and the predictive value of D-dimer for VTE in hospitalized Covid-19 patients.

METHODS

Complete blood count, inflammatory and coagulation biomarkers at admission were collected. VTE was defined as diagnosed pulmonary embolism or deep vein thrombosis. Events were defined as in-hospital death or ICU admission. Predictors of VTE were identified with Pearson prediction models. A ROC curve was constructed to assess the predictive value of D-dimer.

RESULTS

1651 participants were included, 111 VTE were identified. Events incidence was higher in the VTE group (49.5% vs 28.2%, p <  0.001). Neutrophil-lymphocyte ratio (NLR, 0.001; 95% CI 0.000-0.002; p 0.019) and D-dimer (0.00005; 95% CI 0.00002-0.00008; p <  0.001), Geneva score (0.026; 95% CI 0.012-0.040; p <  0.001) and Wells score (0.047; 95% CI 0.033-0.061; p <  0.001) were associated with VTE. D-dimer had a goor predictive value for VTE (ROC area 0.85, 95% CI 0.816-0.893), with an optimal cut-off value of 2677μg/L (Youden index of 0,602).

CONCLUSIONS

Among coagulation biomarkers D-dimer had the best predictive value for VTE, but higher cut-off values should be used in Covid-19.

Harmonization of Hemostasis Testing Across a Large Laboratory Network: An Example from Australia

Harmonization and standardization of laboratory tests and procedures carry a variety of benefits. For example, within a laboratory network, harmonization/standardization provides a common platform for test procedures and documentation across different laboratories. This enables staff to be deployed across several laboratories, if required, without additional training, since test procedures and documentation are the "same" in the different laboratories. Streamlined accreditation of laboratories is also facilitated, as accreditation in one laboratory using a particular procedure/documentation should simplify the accreditation of another laboratory in that network to the same accreditation standard. In the current chapter, we detail our experience regarding the harmonization and standardization of laboratory tests and procedures related to hemostasis testing in our laboratory network, NSW Health Pathology, representing the largest public pathology provider in Australia, with over 60 separate laboratories.

D-dimer Testing in Pulmonary Embolism with a Focus on Potential Pitfalls: A Narrative Review

D-dimer is a multifaceted biomarker of concomitant activation of coagulation and fibrinolysis, which is routinely used for ruling out pulmonary embolism (PE) and/or deep vein thrombosis (DVT) combined with a clinical pretest probability assessment. The intended use of the tests depends largely on the assay used, and local guidance should be applied. D-dimer testing may suffer from diagnostic errors occurring throughout the pre-analytical, analytical, and post-analytical phases of the testing process. This review aims to provide an overview of D-dimer testing and its value in diagnosing PE and discusses the variables that may impact the quality of its laboratory assessment.

D-dimer: old dogmas, new (COVID-19) tricks

D-dimer is a fibrin degradation product encompassing multiple cross-linked D domains and/or E domains present in the original fibrinogen molecule, whose generation is only theoretically possible when hemostasis and fibrinolysis pathways are concomitantly activated. D-dimer measurement has now become a pillar in the diagnosis/exclusion and prognostication of venous thromboembolism (VTE) and disseminated intravascular coagulation (DIC), when incorporated into validated clinical algorithms and especially using age-adjusted diagnostic thresholds. Although emerging evidence is also supporting its use for predicting the duration of anticoagulant therapy in certain categories of patients, the spectrum of clinical applications is constantly expanding beyond traditional thrombotic pathologies to the diagnosis of acute aortic dissection, acute intestinal ischemia and cerebral venous thrombosis among others, embracing also clinical management of coronavirus disease 2019 (COVID-19). Recent findings attest that D-dimer elevations are commonplace in patients with severe acute respiratory syndrome (SARS-CoV-2) infection (especially in those with thrombosis), its value predicts the clinical severity (up to death) of COVID-19 and remains more frequently increased in COVID-19 patients with post-discharge clinical sequelae. Further, D-dimer-based anticoagulant escalation may be associated with a lower risk of death in patients with severe SARS-CoV-2 infection and, finally, D-dimer elevation post-COVID-19 vaccination mirrors an increased risk of developing vaccine-induced thrombocytopenia and thrombosis (VITT).

D-dimers-"Normal" Levels versus Elevated Levels Due to a Range of Conditions, Including "D-dimeritis," Inflammation, Thromboembolism, Disseminated Intravascular Coagulation, and COVID-19

D-dimers reflect a breakdown product of fibrin. The current narrative review outlines how D-dimers can arise in normal individuals, as well as in patients suffering from a wide range of disease states. D-dimers in normal individuals without evident thrombosis can arise from background fibrinolytic activity in various tissues, including kidney, mammary and salivary glands, which ensures smooth flow of arising fluids where any blood contamination could be immediately lysed. In addition, healthy individuals can also regularly sustain minor injuries, often unbeknown to them, and wound healing follows clot formation in these situations. D-dimers can also arise in anxiety and following exercise, and are also markers of inflammation. Lung inflammation (triggered by microbes or foreign particles) is perhaps also particularly relevant, since the hemostasis system and fibrinolysis help to trap and remove such debris. Lung inflammation in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may contribute to D-dimer levels additive to thrombosis in patients with COVID-19 (coronavirus disease 2019). Indeed, severe COVID-19 can lead to multiple activation events, including inflammation, primary and secondary hemostasis, and fibrinolysis, all of which may contribute to cumulative D-dimer development. Finally, D-dimer testing has also found a role in the diagnosis and triaging of the so-called (COVID-19) vaccine-induced thrombotic thrombocytopenia.

A Prospective Study Evaluating Cumulative Incidence and a Specific Prediction Rule in Pulmonary Embolism in COVID-19

Rationale

Abnormal values of hypercoagulability biomarkers, such as D-dimer, have been described in Coronavirus Disease 2019 (COVID-19), which has also been associated with disease severity and in-hospital mortality. COVID-19 patients with pneumonia are at greater risk of pulmonary embolism (PE). However, the real incidence of PE is not yet clear, since studies have been limited in size, mostly retrospective, and PE diagnostic procedures were only performed when PE was clinically suspected.

Objectives

(1) To determine the incidence, clinical, radiological, and biological characteristics, and clinical outcomes of PE among patients hospitalized for COVID-19 pneumonia with D-dimer > 1,000 ng/mL. (2) To develop a prognostic model to predict PE in these patients.

Methods

Single-center prospective cohort study. Consecutive confirmed cases of COVID-19 pneumonia with D-dimer > 1,000 ng/mL underwent computed tomography pulmonary angiography (CTPA). Demographic and laboratory data, comorbidities, CTPA scores, treatments administered, and clinical outcomes were analyzed and compared between patients with and without PE. A risk score was constructed from all these variables.

Results

Between 6 April 2020 and 2 February 2021, 179 consecutive patients were included. The overall incidence of PE was 39.7% (71 patients) (CI 95%, 32–47%). In patients with PE, emboli were located mainly in segmental/subsegmental arteries (67%). Patients with PE did not differ from the non-PE group in sex, age, or risk factors for thromboembolic disease. Higher urea, D-Dimer, D-dimer-to-ferritin and D-dimer-to-lactate dehydrogenase (LDH) ratios, platelet distribution width (PDW), and neutrophil-to-lymphocyte ratio (NLR) values were found in patients with PE when compared to patients with non-PE. Besides, lymphocyte counts turned out to be lower in patients with PE. A score for PE prediction was constructed with excellent overall performance [area under the ROC curve-receiver operating characteristic (AUC-ROC) 0.81 (95% CI: 0.73–0.89)]. The PATCOM score stands for Pulmonary Artery Thrombosis in COVID-19 Mallorca and includes platelet count, PDW, urea concentration, and D-dimer-to-ferritin ratio.

Conclusion

COVID-19 patients with pneumonia and D-dimer values > 1,000 ng/mL were presented with a very high incidence of PE, regardless of clinical suspicion. Significant differences in urea, D-dimer, PDW, NLR, and lymphocyte count were found between patients with PE and non-PE. The PATCOM score is presented in this study as a promising PE prediction rule, although validation in further studies is required.

Evaluation of D-dimer levels measured by different analytical methods in COVID-19 patients

Clinicians experience some challenges due to the lack of standardization of test, although D-dimer is a prognostic marker for COVID-19. We compared the clinical and analytical performances of D-dimer results obtained from different devices, kits and methods in patients with a diagnosis of COVID-19. Thirty-nine patients with a diagnosis of COVID-19 and 24 healthy individuals were included in the study. D-dimer levels were measured with Innovance D-DIMER kit (immunoturbidimetric method) on Sysmex CS-2500 and BCS XP and VIDAS D-Dimer Exclusion II kit (enzyme-linked fluorescence method) on mini VIDAS. The studies of precision, method comparison and clinic performance were performed. The variation coefficients in all systems were within the acceptable imprecision (7.8%). Bias%(12.5%) between BCS XP and Sysmex CS-2500 was lower than the acceptable Bias%(15.5%). Bias% values (19.2% and 33.3%, respectively) between Mini VIDAS with BCS XP and Sysmex CS-2500 were higher than the acceptable Bias%. The correlation coefficients among all systems were 0.89-0.98. For 500 ng/ml FEU, there was almost perfect agreement between BCS XP and Sysmex CS-2500, a moderate agreement between Mini VIDAS and BCS XP and Sysmex CS-2500. The cut-off values for distinguishing between individuals with and withoutCOVID-19 were Mini VIDAS, Sysmex CS-2500 and BCS XP 529, 380 and 390 ng/ml FEU, respectively. The immunoturbidimetric method can be used as an alternative to the enzyme-linked fluorescent method because of satisfactory agreement at the different thresholds proposed for venous thromboembolism. However, it is recommended to follow up COVID-19 with the D-dimer results obtained by the same assay system.