What makes D-dimer assays suspicious-heterophilic antibodies?

D-dimer assay interference detected by the discrepancy in D-dimer concentrations at different dilutions: a case report

This case report describes interference from heterophilic antibodies in D-dimer assay. The interference was suspected due to discrepancies between D-dimer concentrations in the original sample and diluted samples, as well as inconsistent clinical findings. The patient's medical history, laboratory results, and imaging studies were considered in the investigation. Heterophilic antibodies, likely developed during the SARS-CoV-2 infection, were identified as the probable cause of interference. The interference was confirmed through various methods, including dilution studies, blocking heterophilic antibodies, and comparing results with an alternative D-dimer method. This case highlights the importance of recognizing and addressing interference in D-dimer testing, emphasizing the need for collaboration between clinicians and laboratory specialists.

Prognostic value of coagulation markers in patients with colorectal caner: A prospective study

Background and Aims

The occurrence, growth, and metastasis of colorectal cancer (CRC) are connected to the hypercoagulable state of blood (CRC). This study aimed to identify significant coagulation factors to predict metastasis and prognosis of CRC.

Methods

Thrombomodulin (TM), thrombin-antithrombin complex (TAT), α2-plasmininhibitor-plasmin complex (PIC), and tissue plasminogen activator-inhibitor complex (t-PAIC) were detected by chemiluminescence immunoassay using Sysmex HISCL5000 automated analyzers. The Sysmex CS 5100 automatic blood coagulation analyzer was used to detect d-dimer (DD), fibrin degradation product (FDP), prothrombin time (PT), thrombin time (TT), international normalized ratio (INR), fibrinogen (Fbg), and activated partial thromboplastin time (APTT). Area under the curve (AUC) and the receiver operating characteristic curve (ROC) were used to assess the diagnostic efficacy of markers. Kaplan-Meier analysis was used to calculate survival probabilities. Independent prognostic factors and the nomogram were developed using single-factor and multifactor cox regression analysis model.

Results

The following indicators (TM, TAT, PIC, t-PAIC, DD, FDP, PT, INR, APTT, and Fbg) were markedly higher in CRC patients than in healthy controls, and they were higher in the metastasis (M) group than in the nonmetastasis (NM) group. The combination "TAT + PIC + DD + FDP + Fbg" can distinguish M from NM with exceptional sensitivity and specificity. Patients with CRC who had high levels of TAT, PIC, DD, FDP, Fbg, TM, tPAIC, PT, and INR had significantly shorter survival.

Conclusion

The prognosis of CRC patients can be predicted by coagulation indicators. The independent predictive variables for overall survival were found to be TM and DD. To forecast CRC patient survival, a nomogram was created.

Heterophilic antibodies leading to falsely positive D-dimer concentration in an adolescent

Background

We present the case of a 15-year-old adolescent with suspected pulmonary embolism and repeatedly elevated D-dimer levels.

Key Clinical Question

We aim to determine the cause for elevated D-dimer levels in a patient without venous thromboembolism.

Clinical Approach

When the D-dimer measurement was repeated with different assays, D-dimer levels were within the normal reference interval. Dilution series with assay diluent or low-affinity antibody blocking reagents either did not or only partially decreased the D-dimer value using the original reagent kit.

Conclusion

Analyses suggested the presence of interfering heterophilic antibodies in patient plasma, a known phenomenon with immunoturbidimetric D-dimer assays, which is rarely described. Prior to drawing this conclusion, the patient underwent extensive diagnostic testing, which led to uncertainty and discomfort for the health care providers, the patient, and their family.

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.

Falsely elevated D-dimer partially caused by heterophilic antibodies: A case report

Plasma D-dimer is a screening marker for thrombosis and hemostasis disorders. Falsely elevated D-dimer may result in misdiagnosis and potentially invasive investigations. Therefore, identifying falsely elevated D-dimer is of great value in laboratory practice. D-dimer is determined by immunoassay and vulnerable to heterophilic antibody interference. Here, we reported a case of falsely elevated D-dimer partially caused by heterophilic antibodies. Dilution test, polyethylene glycol precipitation, heterophilic blocking reagent and method comparison were used to identify the heterophilic antibody interference. All these methods, except for the heterophilic blocking reagent, revealed the existence of heterophilic antibody interference. Polyethylene glycol precipitation failed to reduce the D-dimer to its reference interval. Therefore, we conclude that the falsely elevated D-dimer is partially caused by heterophilic antibody interference.

Analytical performance of a new immunoturbidimetric D‐dimer assay and comparison with available assays

Background

The routine D‐dimer quantification to exclude venous thromboembolism has led to the development of many assays, the usefulness of which depends on their reliability and performance.

Objective

We evaluated the analytical performances of the immunoturbidimetric Yumizen G DDi 2 assay (HORIBA Medical, Montpellier, France) performed on the Yumizen G800 analyzer and compared it with other available D‐dimer assays.

Methods

Within‐run and between‐run imprecision were evaluated using low‐ and high‐level quality‐control plasma samples. Interference due to hemolysis, icterus, lipemia, rheumatoid factor (RF), or heterophilic antibodies (human antimouse antibodies [HAMAs]) was evaluated by spiking plasma samples with hemolysate, bilirubin, Intralipid, RF, or HAMAs. The measurements obtained with the different D‐dimer assays were compared using Passing‐Bablok regression analysis and Bland‐Altman plot method, using fresh citrated plasma samples collected from 66 consecutive routine patients with a wide range of D‐dimer concentrations.

Results

Within‐ and between‐run variation coefficients for the Yumizen G DDi 2 assay ranged from 1.7% to 5.8% and from 2.8% to 5.5%, respectively. Hemolysis and icterus did not have any effect up to 10 g/L hemoglobin and 300 mg/L bilirubin. Lipemia seemed to generate an underestimation of D‐dimer concentration when the Intralipid concentration was >5 g/L. RF and HAMAs did not have any effect. The Passing‐Bablok and Bland‐Altman analyses showed small differences with other available D‐dimer assays, which were more pronounced with increasing values.

Conclusions

Its analytical performances and main technical features indicate that the new Yumizen G DDi 2 assay is suitable for the rapid quantification of D‐dimer in clinical hemostasis laboratories.

Disseminated Intravascular Coagulation Score and Sepsis-induced Coagulopathy Score in Prediction of COVID-19 Severity: A Retrospective Analysis

BACKGROUND

The novel disseminated intravascular coagulation (DIC) score (platelet count, prolonged prothrombin time, D-dimer, and fibrinogen) and sepsis-induced coagulopathy (SIC) score (platelet count, international normalized ratio, and sequential organ failure assessment score) are markers of coagulopathy, which, for the first time, are explored in line with the coronavirus disease-2019 (COVID-19) disease outcomes. The correlation of D-dimer with these findings is also studied.

MATERIALS AND METHODS

A retrospective analysis of hospital-based records of 168 COVID-19 patients was done. Data including D-dimer, routine investigations, DIC, and SIC scorings (all within 3 days of admission) were collected and correlated with the outcomes. The study was conducted in a tertiary care center catering to North India's population.

RESULTS

Higher DIC score (1.59 ± 1.18 vs 0.96 ± 1.18), SIC score (1.60 ± 0.89 vs 0.63 ± 0.99), and D-dimer titers (1321.33 ± 1627.89 vs 583·66 ± 777.71 ng/mL) were significantly associated with severe COVID-19 disease (p <0.05). DIC score and SIC score ≥1, and D-dimer ≥1315 ng/mL for severe disease; DIC score ≥1, SIC score ≥2, and D-dimer ≥600 ng/mL for pulmonary embolism (PE); and DIC score and SIC score ≥1, and D-dimer level ≥990 ng/mL for mortality were the respective cutoff values we found from our study.

CONCLUSION

Higher DIC scores, SIC scores, and D-dimer values are associated with severe COVID-19 disease, inhospital mortality, and PE risk. They can serve as easily accessible early markers of severe disease and prioritize hospital admissions in the presently overburdened scenario and may be used to develop prognostic prediction models.

HOW TO CITE THIS ARTICLE

Kapoor M, Panda PK, Saini LK, Bahurupi Y. Disseminated Intravascular Coagulation Score and Sepsis-induced Coagulopathy Score in Prediction of COVID-19 Severity: A Retrospective Analysis. Indian J Crit Care Med 2021;25(12):1357-1363.

Different diagnostic performance of plasma fibrinogen and D-dimer in periprosthetic joint infection: a propensity score matched study

Background

Fibrinogen (Fbg) and D-dimer have been used as biomarkers for the diagnosis of periprosthetic joint infection (PJI). However, previous research has reported conflicting results on the diagnostic value of D-dimer in comparison to Fbg, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR).

Aim

This study aimed to: (1) determine the optimal threshold of plasma Fbg and D-dimer in the diagnosis of PJI and compare their diagnostic value to that of CRP and ESR; and (2) investigate whether Fbg and D-dimer perform differently than CRP and ESR as diagnostic indicators for different types of PJI.

Methods

A total of 115 revision cases after total hip arthroplasty (THA) and total knee arthroplasty (TKA) were identified. Based on demographic characteristics, 25 culture-positive cases were matched to 50 culture-negative cases using propensity score matching. Sensitivity, specificity, receiver operating characteristics (ROC), negative predictive value (NPV), and positive predictive value (PPV) were calculated and compared.

Results

The optimal thresholds were 2.72 mg/L for D-dimer, 3.655 g/L for Fbg, 12.64 mg/L for CRP, and 27 mm/h for ESR. Levels of plasma Fbg, D-dimer, CRP, and ESR were significantly higher in the culture-positive group than the culture-negative group. Fbg, D-dimer, CRP, and ESR showed sensitivity of 0.92, 0.56, 0.92, and 0.88, respectively, and showed specificity of 0.84, 0.96, 0.94, and 0.80, respectively. The ROC curve showed that CRP has the highest area under the curve (AUC) (0.94), followed by Fbg (0.90), ESR (0.87), and D-dimer (0.81).

Conclusions

Plasma Fbg exhibited a similar diagnostic performance compared to CRP and ESR in predicting culture-positive results in PJI. Plasma D-dimer showed high specificity but low sensitivity. In our study, Fbg and D-dimer did not show better diagnostic performance with different pathogens and different types of PJI. Further studies are required to investigate the difference between serum D-dimer and plasma D-dimer in the arthroplasty population.

Use and misuse of biomarkers and the role of D-dimer and C-reactive protein in the management of COVID-19: A post-hoc analysis of a prospective cohort study

OBJECTIVE

Coronavirus disease 2019 (COVID-19) is associated with high mortality among hospitalized patients and incurs high costs. Severe acute respiratory syndrome coronavirus 2 infection can trigger both inflammatory and thrombotic processes, and these complications can lead to a poorer prognosis. This study aimed to evaluate the association and temporal trends of D-dimer and C-reactive protein (CRP) levels with the incidence of venous thromboembolism (VTE), hospital mortality, and costs among inpatients with COVID-19.

METHODS

Data were extracted from electronic patient records and laboratory databases. Crude and adjusted associations for age, sex, number of comorbidities, Sequential Organ Failure Assessment score at admission, and D-dimer or CRP logistic regression models were used to evaluate associations.

RESULTS

Between March and June 2020, COVID-19 was documented in 3,254 inpatients. The D-dimer level ≥4,000 ng/mL fibrinogen equivalent unit (FEU) mortality odds ratio (OR) was 4.48 (adjusted OR: 1.97). The CRP level ≥220 mg/dL OR for death was 7.73 (adjusted OR: 3.93). The D-dimer level ≥4,000 ng/mL FEU VTE OR was 3.96 (adjusted OR: 3.26). The CRP level ≥220 mg/dL OR for VTE was 2.71 (adjusted OR: 1.92). All these analyses were statistically significant (p<0.001). Stratified hospital costs demonstrated a dose-response pattern. Adjusted D-dimer and CRP levels were associated with higher mortality and doubled hospital costs. In the first week, elevated D-dimer levels predicted VTE occurrence and systemic inflammatory harm, while CRP was a hospital mortality predictor.

CONCLUSION

D-dimer and CRP levels were associated with higher hospital mortality and a higher incidence of VTE. D-dimer was more strongly associated with VTE, although its discriminative ability was poor, while CRP was a stronger predictor of hospital mortality. Their use outside the usual indications should not be modified and should be discouraged.

Verification of automated latex-enhanced particle immunoturbidimetric D-Dimer assays on different analytical platforms and comparability of test results

INTRODUCTION

The aim of the study was the analytical verification of automated latex-enhanced particle immunoturbidimetric (LPIA) D-Dimer assay INNOVANCE D-dimer on Sysmex CS-5100 and Atellica COAG 360 analysers, and HemosIL D-dimer HS500 on ACL TOP 550, as well as the comparison with the enzyme-linked immunofluorescent assay (ELFA) on the miniVidas analyser.

MATERIALS AND METHODS

Verification included assessment of within-run and between-run precision, bias, measurement uncertainty (MU), verification of the cut-off, method comparison between all assessed assays, and the reference commercial ELFA VIDAS D-Dimer Exclusion II.

RESULTS

Within-run coefficients of variations (CVs) ranged from 1.6% (Atellica COAG 360) to 7.9% (ACL TOP 550), while between-run CVs ranged from 1.7% (Sysmex CS-5100) to 6.9% (Atellica COAG 360). Spearman's rank correlation coefficients were > 0.99 between LPIAs and ≥ 0.93 when comparing ELFA with LPIA. Passing-Bablok regression analysis yielded constant and proportional difference for comparison of ACL TOP 550 with both Sysmex CS-5100 and Atellica COAG360, and for miniVidas with Atellica COAG360. Small proportional difference was found between miniVidas and both Sysmex CS-5100 and ACL TOP 550. Calculated MUs using D-dimer HS 500 calibrator were 12.6% (Sysmex CS-5100) and 15.6% (Atellica COAG 360), while with INNOVANCE D-dimer calibrator 12.0% (Sysmex CS-5100), 10.0% (Atellica COAG 360) and 28.1% (ACL TOP 550). Excellent agreement of results was obtained, with occasional discrepancies near the cut-off. The cut-off (0.5 mg/L FEU) was confirmed.

CONCLUSIONS

The obtained results prove satisfactory analytical performance of LPIAs, their high comparability and almost equal discriminatory characteristics, suggesting them as a valid alternative to ELFA.

Clinical laboratory investigation of a patient with an extremely high D-dimer level: A case report

BACKGROUND

D-dimer, a soluble degradation product of cross-linked fibrin, is commonly used as an important marker for the diagnosis of disseminated intravascular coagulation and differential diagnosis of thrombosis. Herein, we present a geriatric case with an unusually elevated D-dimer level.

CASE SUMMARY

An 82-year-old woman, admitted to the ward with a diagnosis of chronic heart failure, was noted to have a remarkably elevated D-dimer level, beyond the qualified range (> 100 mg/L), utilizing the Innovating D-dimer for Sysmex CS-5100 System™. However, no evidence, including clinical symptoms, radiographic evidence of thromboembolic disease, and parallel fibrinogen degradation product values, suggested that this patient was at high risk of thrombopenia. To confirm the discrepancy, a series of approaches including sample dilution, re-analysis via alternative methods, and sample treatment with blockage of specific heterophilic antibodies were performed. A remarkable disappearance of the elevated D-dimer values was observed in the samples after they were subjected to these approaches (4.49, 9.42, 9.06, and 12.58 mg/L, respectively). This confirmed the presence of heterophilic antibodies in this case. In addition, a reduction in cardiac output due to the presence of cardiac failure could also be responsible for the existence of a hypercoagulable state in this case.

CONCLUSION

In conclusion, the presence of heterophilic antibodies should be considered when an elevated D-dimer value is not in conformity with the clinical evidence, and a viral infection should be considered when interference by a heterophilic antibody exists.

Value of TAT and PIC with D-dimer for cancer patients with metastasis

INTRODUCTION

The hypercoagulability of blood is related to the development and metastasis of cancer. High levels of D-dimer have been reported to be associated with the metastasis and poor prognoses of cancer. Here, we investigated the performance of biomarkers-TAT, PIC, TM, and tPAI·C by new method-for monitoring cancer patients with metastasis.

METHODS

A total of 197 cancer patients were enrolled. TM, TAT, PIC, and tPAI·C were detected by the chemiluminescence immunoassay.

RESULTS

Results showed that the levels of TAT and PIC were higher in the metastasis group than those in the nonmetastasis group (P < .01). In the nonmetastasis group, there were 16 patients with elevated levels of D-dimer. But, TAT and PIC in these 16 patients were all at normal level (<0.55 mg/L FEU). After dilution, D-dimer was also decreased to normal levels in these 16 patients. The ROC was used to show the performance of D-dimer, TAT, and PIC on indicating cancer with metastasis. The AUC of PIC was higher than that of D-dimer (0.825 vs. 0.770). The specificity and PPV of TAT and PIC were higher than those of D-dimer. Serial test of TAT, PIC, and D-dimer improved the specificity and positive predictive value to 90.91% [80.61%, 96.25%] and 89.29% [77.45%, 95.57%], respectively.

CONCLUSION

Combining TAT and PIC with D-dimer could be useful surveillance biomarkers for cancer with metastasis.

False-positive troponin I elevation in a newborn with neonatal encephalopathy

Serum biomarkers of myocardial damage are commonly used in babies after perinatal asphyxia. We present a case report of a persistently troponin I elevation without evidence of clinical or instrumental signs of myocardial ischaemia in a baby with perinatal asphyxia. When the blood was mixed with polyethylene glycol we found that the troponin I levels were falsely elevated due to interfering antibodies. This case shows that analytical errors may still occur despite modern immunoassay systems and underlines the need for further investigations to identify false-positive values in case of disagreement between clinical conditions and laboratory values.

What makes D-dimer assays suspicious-heterophilic antibodies?

BACKGROUND

Heterophilic antibodies are still an important source of interference in immunoassays, but reports of interference with D-dimers are rare. Are D-dimer level abnormalities, found in the clinic, caused by heterophilic antibodies as well, or are other mechanisms involved? We will elaborate on this issue through two different examples in this article.

METHODS

Serum from two patients with significantly elevated levels of D-dimers were measured and compared by different methods, diluted, and dealt with heterophilic antibody blockers. At the same time, to retrieve the interference, we focused on the cause of D-dimer false positives and made a systematic review of the literature.

RESULTS

The D-dimer values were normal (0.49 and 0.15 μg/mL) detected with different testing method and decreased after addition of heterophilic antibody blocking reagent. According to literature data, there were 66.7% (4/6) references showed the interference were heterophilic antibody.

CONCLUSIONS

The influence of heterophilic antibodies on the measurement of D-dimers remains a big challenge. Different measuring instruments and methods may have significant differences in the measurement of D-dimers. By using a combination of instrumental methods for measuring, incorporating heterophilic antibody blockers, and combining with clinical performance and imaging data, most of the interference can be eliminated.