Clauss Method Research Articles

Association of results of the glutaraldehyde coagulation test with plasma acute phase protein concentrations and hematologic findings in hospitalized cows.

The glutaraldehyde test (GAT) allows for animal-side semi-quantitative estimation of fibrinogen and gamma-globulin concentrations in blood samples of adult cattle and therefore detection of inflammatory disease conditions. However, the test has potential limitations, especially due to the latency period until sufficiently high fibrinogen and/or gamma-globulin concentrations are reached. The aim of the present study was therefore to assess the association between results of GAT with other inflammatory markers including hematologic variables, fibrinogen, plasma haptoglobin and serum amyloid A (SAA) concentrations. For the purpose of this prospective observational study, a convenience sample of 202 cows with a broad range of inflammatory and non-inflammatory clinical conditions was included. The GAT was run on EDTA blood, fibrinogen was measured using the Clauss and the heat precipitation method, and commercially available ELISA tests were used for determination of plasma haptoglobin and SAA concentrations. Shortened GAT coagulation times were more closely correlated to serum globulin (rs = -0.72) than to plasma fibrinogen concentrations measured with the heat precipitation (rs = -0.64) and the Clauss method (rs = -0.70). Cows with a markedly (≤3 min) or moderately (4-6 min) shortened coagulation time had higher (p < 0.001) plasma haptoglobin and SAA concentrations than cows with a negative test result. Total leukocyte, monocyte and neutrophil concentrations did not differ significantly between groups. An identified cut-off for the GAT coagulation time of ≤14 min had a sensitivity and specificity of 54.4 and 100%, respectively, for the prediction of an inflammatory state based on clinical findings and/or increased plasma haptoglobin or SAA concentrations. In conclusion, this study demonstrates considerable diagnostic agreement between positive GAT results and increased plasma concentrations of haptoglobin and SAA. Despite high specificity, the test lacks sensitivity in case of acute inflammatory conditions indicating that plasma acute phase protein concentrations and hematologic findings can provide additional diagnostic information if the GAT is negative.

Improving the Application of Prothrombin Time-Derived Fibrinogen Assay Through Value Transfer from the Von Clauss Method.

This study aimed to improve the accuracy of the fibrinogen (Fib) prothrombin time-derived (PT-der) method. To achieve this, a value transfer method was introduced for calibration, and its effectiveness was assessed. The PT-der Fib assay was calibrated by pooled samples (assigned by the von Clauss method) in three different ways: 1) multipoint calibration using an automatic dilution system, 2) multipoint calibration using a manual dilution method, and 3) manual calibration with multiple concentrations. Three calibration equations (1, 2, and 3) were obtained and an optimal equation was selected by comparing the detection results of the von Clauss method with the PT-der method. Subsequently, the optimal equation was assessed for an accuracy limit, and linear analysis and reference interval verification were performed following the guidelines (EP15-A and EP6-A) issued by the CLSI. Compared with the other two equations (equation 1 and 2), equation 3, available from manual calibration with multiple concentrations, showed a better performance for the PT-der determination in a primary cohort (n = 208), and a good agreement (99% of the results between 1.52 and 6.30 g/L were interchangeable) was validated (n = 3226). The reference interval was also verified in almost all healthy individuals (39/40). However, the discrep-ancy between the two methods was observed in several specific conditions, such as hyperfibrinolysis. Manual calibration with multiple concentrations is better for the Fib PT-der method assay. As a rapid, accurate, and economical test, the performance of the Fib PT-der method has been verified and may be more applicable than before.

Accuracy of rapid blood coagulation testing device FibCare® in a tertiary emergency department.

FibCare® is a novel point-of-care testing device enabling prompt evaluation of fibrinogen levels. This study aimed to investigate the accuracy of FibCare® at a tertiary emergency department. Blood specimens obtained at a tertiary emergency medical center between October 1, 2021, and April 30, 2023, were evaluated. The correlation between the fibrinogen levels assessed via FibCare® and those via the Clauss method was evaluated using the Spearman's test. The discrepancy between the two measurement methods was assessed according to fibrinogen level and diagnosis. A total of 177 specimens from 147 patients were eligible for the analysis. The median age of the patients was 49 years, and 109 (61.6%) were men. The two measurements had statistically significant but moderate correlation (p < 0.001, ρ = 0.76). FibCare® missed 14 out of 35 cases from patients with hypofibrinogenemia (fibrinogen ≤150 mg/dL assessed by the Clauss method). The discrepancy between the two measurements was significantly greater in specimens with lower fibrinogen levels and those obtained from patients following trauma. FibCare®, a novel point-of-care testing device, can be compatible with the Clauss method. However, clinicians should be aware of the risk that FibCare® may underestimate fibrinogen reduction, especially in severe cases and trauma cases.

Insulin resistance, vascular dysfunction and inflammation biomarkers associations with an increased CAIDE risk score in APOE‐ε4 carriers with subjective cognitive decline from the PENSA study

AbstractBackgroundThe CAIDE (Cardiovascular Risk Factors –CVRF‐, Aging, and Incidence of Dementia) Dementia Risk Score is a validated tool to predict late‐life dementia risk based on midlife CVRF. Sex differences in metabolic pathways related to cognitive decline have been described. The aim of this study was to explore associations between measures of insulin resistance, biomarkers of endothelial activation and peripheral inflammation and an increased CAIDE risk score (CAIDE‐rs) in individuals at higher risk of Alzheimer’s disease (AD). Sex differences in these associations were explored.MethodA total of 129 participants of the PENSA study were recruited. Participants were categorized into high (≥ 9 points) or low CAIDE‐rs groups (HR and LR respectively). Homeostatic model assessment was calculated (HOMA IR = fasting insulin (μIU/ml) × fasting glucose (mmol/ml)/22.5). The following biomarkers were analyzed: soluble intercellular adhesion molecule‐1 (ICAM‐1, ng/ml), vascular cell activation molecule‐1 (VCAM‐1, ng/ml), C‐reactive protein (CRP, mg/dl) and fibrinogen (mg/dl), using ELISA and Clauss method assays.ResultParticipants were 67.2 ±4.8 years, 65.1% were women and 32.6% were classified into the HR group. The HR group was older (68.5 vs. 66.5 years, P = 0.026) and presented higher levels of CRP (median of 0.08 vs. 0.06 mg/dL; P = 0.037) and HOMA‐IR (2.1 vs. 1.6; P = &lt;.001). No differences were found for ICAM‐1, VCAM‐1 or fibrinogen.Comparisons between sex groups showed higher fibrinogen median values in women both among the HR group and in the global sample (HR 372 vs. 327mg/dl; P = 0.011; GS 350.5 vs. 340.5mg/dl; P = 0.032). Higher HOMA‐IR and VCAM‐1 median values in men were found in the global sample (2.13 vs. 1.65; P = 0.006 and 495.8 vs. 434.5 ng/ml; P = 0.028). The HR female group showed higher HOMA‐IR and fibrinogen median values than the LR female group (2.06 vs. 1.58; p = &lt;.001 and 372 vs. 343 mg/dl; P = 0.029 respectively). HR male group showed higher CRP values compared to LR male group (0.03 vs. 0.12 mg/dl; p = 0.026).ConclusionAssociations of metabolic alterations and an increased CAIDE‐rs were found in individuals at higher risk of AD. Moreover, sex differences in metabolic alterations were also found. These results highlight the necessity of personalizing preventive interventions for AD taking into account sex‐related profiles.

The correlation between Plasma Fibrinogen Levels and Glycemic Status in type 2 Diabetes Mellitus

Abstract Introduction/Objective Background: Fibrinogen is considered a well-known contributor to the progression of atherosclerotic lesions and a predictor of cardiovascular events. Patients with diabetes mellitus (DM) have higher levels of fibrinogen, which may raise their thromboembolic risk for cardiovascular disease (CVD). Plasma fibrinogen is an indicator of inflammation, and endothelial dysfunction has been described as an independent risk factor for cardiovascular morbidity in type-2 diabetes mellitus (T2DM) patients. Poor glycemic control has been reported to be associated with hyperfibrinogenemia. Aim This study aims to estimate the levels of fibrinogen in patients with type-2 diabetes mellitus and determine its correlation with glycated hemoglobin levels. Methods/Case Report Subjects and methods: It is a cross-sectional analytic study conducted in the Benghazi Diabetic Clinic, Libya. Patients who were diagnosed with type 2 diabetes mellitus, either newly detected or already on diet or treatments, were included in the study during the period between May 2022 to December 2022. A total of 231 adult subjects were selected, with ages ranging from 20-80 years. Random blood sugar levels were assessed. Plasma fibrinogen levels (mg/dl) were estimated by the "Clauss method" and glycosylated hemoglobin (%) by the "immunoturbidimetric method." Patients were categorized into three groups depending upon the HbA1c values, i.e., into &amp;lt;5.7% (good control), 5.7-6.5% (fair control), and &amp;gt;6.5% (poor control). Results (if a Case Study enter NA) Result: Out of 231 subjects, (40.6%) were males and (59.4%) were females, with a mean±SD of age was (47.03±15.54) years. There was a significant positive correlation between fibrinogen and HbA1c in the fair control group (r=0.424, p=0.003) and the poor control group (r=0.369, P=0.000). Moreover, the difference between fibrinogen and age in the good control group was significant (p&amp;gt;0.05), whereas no significance was recognized in other groups. Conclusions Plasma fibrinogen levels are elevated in type 2 DM, and this elevation was associated with poor glycemic control; increased HbA1c levels. The other parameters which correlated with plasma fibrinogen levels were age. Lowering plasma fibrinogen levels could be an integral approach to cardiovascular complications reduction in type-2 DM.

Genetic analysis of a Chinese pedigree affected with Congenital dysfibrinogenemia due to variant of FGG gene

To explore the coagulation deficit and genetic basis for a Chinese pedigree affected with Congenital dysfibrinogenemia (CD). Peripheral venous blood samples of the proband and her family members (including 4 individuals from three generations) were subjected to routine blood test and assays of liver and kidney functions and viral hepatitis to exclude related diseases. Clauss method and DFg-PT method were used to determine the fibrinogen activity (Fg:C), and an immunoturbidimetric assay was used to determine the level of fibrinogen antigen (Fg:Ag). All of the exons (22 in total) and their flanking sequences of the FGA, FGB and FGG genes were amplified by PCR and directly sequenced. Variants in the coding regions of the three genes and transcriptional splicing sites were screened by using Mutation SurveyorTM software. The Clauss method showed that Fg:C was significantly reduced in the proband and her father, whilst her mother and son were normal. With the DFg-PT method, the proband, her parents and son were all within the normal range. The Fg:C/Fg:Ag ratio of the proband and her father was lower than 0.7, whilst her mother and son were above 0.7. No significant change in the prothrombin time, activated partial thromboplastin clotting time and thrombin time was noted. Two genetic variants were detected, which included a homozygous missense variant in the FGA gene [c.991A>G (p.Thr331Ala)], which was predicted to be benign, and a heterozygous missense variant of the γ chain of the FGG gene [c.1211C>G (p.Ser404Phe)], which is located in a conserved region and unreported in the CLINVAR/HGMD/EXAC/1000G databases and literature. This pedigree has conformed to the autosomal dominant inheritance of CD. The c.1211C>T (p.Ser404Phe) missense variant of the γ chain of the FGG gene probably underlay the pathogenesis of CD in this pedigree. The variant was unreported previously and named as "Fibrinogen Harbin II Ser404Phe".

Development of biosensors for detection of fibrinogen: a review.

Fibrinogen as a major inflammation marker and blood coagulation factor has a direct impact on the health of humanity. The variations in fibrinogen content lead to risky conditions such as bleeding and cardiovascular diseases. So, accurate methods for monitoring of this glycoprotein are of high importance. The conventional methods, such as the Clauss method, are time consuming and require highly specialized expert analysts. The development of fast, simple, easy to use, and inexpensive methods is highly desired. In this way, biosensors have gained outstanding attention since they offer means for performing analyses at the points-of-care using self-testing devices, which can be applied outside of clinical laboratories or hospital. This review indicates that different electrochemical and optical sensors have been successfully implemented for thedetection of fibrinogen under normal levels of fibrinogen in plasma. The biosensors for thedetection of fibrinogen have been designed based on the quartz crystal microbalance, field-effect transistor, electrochemical impedance spectroscopy, amperometry, surface plasmon resonance, localized surface plasmon resonance, and colorimetrictechniques. Also, this review demonstrates the utility of the application of nanoparticles in different detection techniques.

A Family with Congenital Dysfibrinogenemia and Blood Transfusion

To investigate a family with congenital dysfibrinogenemia, and analyze the risk of hemorrhage and thrombosis and blood transfusion strategies. Prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) of the proband and her family members were detected by automatic coagulometer, fibrinogen (Fg) activity and antigen were detected by Clauss method and PT algorithm respectively. Meanwhile, thromboelastometry was analyzed for proband and her family members. Then, peripheral blood samples of the proband and her family members were collected, and all exons of FGA, FGB and FGG and their flanks were amplified by PCR and sequenced to search for gene mutations. The proband had normal APTT and PT, slightly prolonged TT, reduced level of Fg activity (Clauss method). The Fg of the proband's aunt, son and daughter all decreased to varying degrees. The results of thromboelastogram indicated that Fg function of the proband and her family members (except her son) was basically normal. Gene analysis showed that there were 6233 G/A (p.AαArg35His) heterozygous mutations in exon 2 of FGA gene in the proband, her children and aunt. In addition, 2 polymorphic loci were found in the family, they were FGA gene g.9308A/G (p.AαThr331Ala) and FGB gene g.12628G/A (p.BβArg478Iys) polymorphism, respectively. The proband was injected with 10 units of cryoprecipitate 2 hours before delivery to prevent bleeding, and no obvious bleeding occurred during and after delivery. Heterozygous mutation of 6233G/A (p.AαArg35His) of FGA gene is the biogenetic basis of the disease in this family with congenital dysfibrinogenemia.

Hemostatic system in Takotsubo patients at long-term follow-up: A hidden activation?

BackgroundTakotsubo cardiomyopathy (TTS) has long been considered a benign condition, despite recurrent events and long-term adverse outcomes are often reported. Endothelial damage, blood hyperviscosity, and platelet activation described in acute phase persist in long-term follow-up; however, TTS pathophysiology is still not fully understood. Here, we explored the hemostatic system at a median of 3.1 years after TTS to uncover additional long-lasting changes in these patients. MethodsWe assessed hemostatic parameters in women with TTS (n = 23) or coronary artery disease (CAD; n = 31) and in control women (n = 26) age-matched, by thromboelastographic analysis, prothrombin time (PT) and partial thromboplastin time (aPTT) coagulation assays and microparticle exposing Tissue Factor (MP-TF). Functional fibrinogen and fibrin polymerization were analyzed by Clauss method and spectrophotometry, respectively. Platelet reactivity was evaluated by light transmission aggregometry, whereas plasminogen activator inhibitor-1 (PAI-1) and brain-derived neurotrophic factor (BDNF) were measured by ELISA kit. ResultsCompared with control subjects, TTS patients exhibit an accelerated clot formation, higher percentage of fibrin polymerization and higher PAI-1 levels. Compared with CAD, TTS patients showed sustained residual platelet activation but decreased functional fibrinogen, fibrin polymerization and MP-TF levels, prolonged aPTT and a marked BDNF increase. ConclusionsThe long-term activation of hemostatic system observed in TTS patients compared to control subjects suggests a persistent humoral abnormality that may be related to the propensity for TTS recurrence. The higher residual platelet activity observed in TTS than in CAD patients invites investigation on TTS-tailored antiplatelet therapy potentially needed to prevent TTS adverse outcomes.

Overestimation of fibrinogen concentration in cryoprecipitate by repeated freeze-thawing with long thawing period as used in the Clauss method.

Cryoprecipitate (CRY) is widely used for treating acquired hypofibrinogenemia. During our study to determine an optimal preparation method, we noticed that the measurement of fibrinogen concentration in CRY had a risk of overestimation. We analyzed this condition and mechanism. CRY was prepared from fresh frozen plasma (FFP) under four conditions: A, 30 h thawing time, 2 cycles; B, 24 h thawing time, 2 cycles; C, 30 h thawing time, 1 cycle; and D, 24 h thawing time, 1 cycle. Then, fibrinogen concentrations in CRY and cryosupernatant (CS) were measured by the Clauss method. Purification (CRY/CRY+CS) and recovery (CRY/FFP) rates in CRY prepared under 2-cycle conditions were higher than those under 1 cycle. However, recovery rates often exceeded 100%, particularly in the case of CRY prepared under A condition, and fibrinogen concentrations calculated by direct measurement were higher than those indirectly calculated from FFP and CS, suggesting an overestimation of fibrinogen values. The level of soluble fibrin monomer complex was considerably higher in CRY prepared under A than under D condition, indicating that CRY adopted a hypercoagulated state. We further found that repeated thawing/freezing increased fibrinogen values as measured by the Clauss method while mechanical vortexing did not. Our findings suggest that direct assessment of fibrinogen contents in CRY prepared by repeated freeze-thawing with a longer thawing period presents a higher risk of overestimation. For the purpose of quality control, we propose an alternative method to indirectly estimate fibrinogen concentrations in CRY from those of CS and FFP.

Dysfibrinogenemia: discrepant results following infusion of purified fibrinogen.

Inherited dysfibrinogenemias are molecular disorders of fibrinogen that affect fibrin polymerization. The majority of cases are asymptomatic, but a significant proportion suffer from increased bleeding or thrombosis. We present two unrelated cases of dysfibrinogenemia, both of whom showed a characteristic discrepancy between fibrinogen activity and the immunologic fibrinogen. In one patient, the dysfibrinogenemia was confirmed by molecular analysis; in the other case, the diagnosis was presumptive based upon laboratory studies. Both patients underwent elective surgery. Both received a highly purified fibrinogen concentrate preoperatively and demonstrated a suboptimal laboratory response to the infusion. Three methods for determining fibrinogen concentration (Clauss fibrinogen, prothrombin-derived fibrinogen, and the viscoelastic functional fibrinogen) were utilized in the case of one patient, and these techniques showed discrepant results with the classic Clauss method giving the lowest concentration. Neither patient experienced excessive bleeding during surgery. Although these discrepancies have been previously described in untreated patients, their manifestation after infusion of purified fibrinogen is less well appreciated.

Influence of Heparin on Fibrinogen Assay by Clauss Method

Objective: To investigate the effect of heparin on fibrinogen detection by Clauss method. Methods: A normal plasma pool (NPP) of 20 healthy people was prepared with 3.2% sodium citrate anticoagulant. For experimental group 1, samples containing different concentrations of heparin were prepared. For experimental group 2, samples of experimental group 1 were diluted twice. For experimental group 3, samples of experimental group 1 were diluted 4 times. For the control group, samples of normal saline with the same volume as heparin in experimental group 1 were prepared. The fibrinogen contents of experimental group 1, experimental group 2, experimental group 3, and control group were detected by Clauss method and prothrombin time (PT)-derived method, and the fibrinogen detection results of different groups were analyzed. Results: The trend of fibrinogen detected by Clauss method and PT-derived method in experimental group 1 was different; there was significant difference between the results of experimental group 1 and the control group (P &lt; 0.05); there was no significant difference between the results of experimental group 2 and the control group (P &gt; 0.05); there was no significant difference between the results of experimental group 3 and the control group (P &gt; 0.05); there was no significant difference between the results of experimental group 2 and experimental group 3 (P &gt; 0.05); the relative deviation between experimental group 1 and the control group was higher in high-concentration heparin sample. Conclusion: Heparin affects fibrinogen detection by Clauss method, and the effect can be reduced by sample dilution.

Fibcare® shows correlation with fibrinogen levels by the Clauss method during cardiopulmonary bypass.

Central laboratory measurements are time consuming, while rapid fibrinogen level measurements within the operating room improve transfusion strategies. We aimed to clarify the correlation between fibrinogen concentrations (measured using Fibcare® and the Clauss fibrinogen assay in a central laboratory) during cardiovascular surgery with cardiopulmonary bypass. Data of patients whose Fibcare, traditional laboratory-based testing, and thromboelastographic results were measured using the same blood sample during cardiopulmonary bypass from February 2021 to January 2022 were retrospectively examined. We analyzed correlation in categories of body temperature during cardiopulmonary bypass: total cases, mild hypothermia (28-34°C), and moderate or severe hypothermia (<28°C). The Clauss fibrinogen assay was performed in 123 cases, Fibcare in 107, and thromboelastography in 91. For mild hypothermia, moderate or severe hypothermia, and overall, the root mean squared error and R-square in Fibcare were 16.1 and 0.86, 13.1 and 0.87, and 14.9 and 0.87, respectively, and for thromboelastography, they were 3.26 and 0.74, 2.70 and 0.79, and 3.08 and 0.75, respectively. A significant relationship was noted between Fibcare and Claus fibrinogen analysis regardless of body temperature during cardiopulmonary bypass. The measurement of fibrinogen levels using Fibcare allows for faster transfusion preparation than that of the traditional Clauss fibrinogen assay.

Potential for prolongation of fibrinogen concentrates post-reconstitution

Background and objectivesReconstituted fibrinogen concentrate is considered stable for 8–24 h based on product monographs. Given the long half-life of fibrinogen in vivo (3–4 days), we hypothesized that reconstituted sterile fibrinogen protein would remain stable longer than 8–24 h. Extending the expiry date for reconstituted fibrinogen concentrate could decrease wastage and facilitate reconstitution in advance to minimize turnaround times. We performed a pilot study to define the stability of reconstituted fibrinogen concentrates over time. Materials and methodsReconstituted Fibryga® (Octapharma AG) from 64 vials was stored in the temperature-controlled refrigerator (4 °C) for up to 7 days with functional fibrinogen concentration measured serially using the automated Clauss method. The samples were frozen, then thawed and diluted with pooled normal plasma in order for them to be batch tested. ResultsReconstituted fibrinogen samples stored in the refrigerator showed no significant reduction in functional fibrinogen concentration for the entire 7-day study period (p = 0.63). Duration of initial freezing had no detrimental effect on functional fibrinogen levels (p = 0.23). ConclusionFibryga® can be stored at 2–8 °C post-reconstitution for up to one week with no loss in functional fibrinogen activity based on Clauss fibrinogen assay. Further studies with other fibrinogen concentrate formulations and clinical in vivo studies may be warranted

Fibrinogen level among children with liver cirrhosis

IntroductionThe liver has a major role in the production of coagulation factors, and cirrhotic patients have a series of coagulopathy disorders. The present study aimed to measure plasma fibrinogen levels in children with hepatic cirrhosis.MethodPatients younger than 18 years old after diagnosis of liver cirrhosis by biopsy were enrolled in the study. Laboratory data including hemoglobin, PT, PTT, INR, and liver function tests were recorded. Fibrinogen levels were measured using the Clauss method. PELD score for children less than 12 years and MELD Na for children over 12 years were used to measure the severity of the liver disease.ResultsFifty children with cirrhosis were studied. The mean fibrinogen level in the “PELD < 15” group was significantly higher than the other group (P < 0.001). There was no significant relationship between bleeding and fibrinogen levels. There was no significant relationship between PELD and bleeding in subjects (P = 0.87). The results of the study showed neither of these two factors (fibrinogen level and PELD) can play a predictive role in causing hemorrhage in patients.ConclusionOur study has shown that fibrinogen level is significantly associated with severity of liver cirrhosis and decreases with more severe disease (PELD levels), but platelet and fibrinogen cannot predict the severity of bleeding in these patients.

Iatrogenic Reversible Hypofibrinogenemia in the Setting of Using a Direct Thrombin Inhibitor for Treatment for Recurrent Deep Vein Thrombosis

Fibrinogen is an essential and abundant peptide synthesized by the liver. It is required for clot formation while providing a matrix and mesh network essential for clot strength. It is used in the diagnosis and monitoring of multiple coagulopathies. The gold standard for measuring fibrinogen is the Clauss method which uses citrated plasma to which thrombin is added, and the clot formation time is recorded via spectroscopic analysis. Hypofibrinogenemia is defined as fibrinogen of less than 150 mg/dL and is primarily treated with supplementation with cryoprecipitate, or a fibrinogen concentrate. Acquired hypofibrinogenemia may occur due to disseminated intravascular coagulopathy (DIC), liver failure, after cardiac surgery or after massive transfusions. There have also been reports of hypofibrinogenemia associated with the use of direct thrombin inhibitors and tPA. We present a case of acquired hypofibrinogenemia while being treated for recurrent deep vein thrombosis (DVT) which was able to be reversed with the cessation of the direct thrombin inhibitor. A 28-year-old female presented to the emergency department with left lower extremity pain, swelling and cyanosis. She was diagnosed with an extensive DVT of the left lower extremity and started on a heparin infusion. She subsequently underwent mechanical thrombectomy, IVC filter placement and iliac vein stenting due to extensive clot burden. She was transitioned to weight-based therapeutic enoxaparin and discharged home. However, despite her compliance, she continued to have worsening left lower extremity pain and swelling and was found to have a persistent DVT. She was then tried on apixaban but failed therapy and required a repeat thrombectomy due to clinical worsening of her lower extremity exam. Her initial hypercoagulability workup for anti-phospholipid syndrome was unremarkable. She then underwent catheter-directed tPA and was started on an argatroban infusion. She remained on the argatroban infusion for 7 days. While on argatroban infusion therapy, routine blood work noted her fibrinogen levels to be less than 50 mg/dL. Despite the initial concern for DIC, the hypofibrinogenemia was ultimately attributed to prolonged argatroban exposure after literature review. The decision was made to not replace the fibrinogen, but instead to transition the argatroban to fondaparinux. The repeat fibrinogen level one day after discontinuing argatroban was back to normal limits at 351 mg/dL and the patient was subsequently discharged on fondaparinux with subsequent clinical improvement. Multiple studies advocate for maintaining fibrinogen levels with supplementation for acquired coagulopathies. However, in this clinical situation, removing the offending agent was the key to correcting the patient's fibrinogen level. With the patient's history of recurrent DVTs, giving her fibrinogen replacement may have led to worsening thrombosis and adverse events. It is imperative that clinicians be aware of the many causes of hypofibrinogenemia. Before reflexively replacing fibrinogen, a physician must consider all reversible causes and make an informed clinical decision.

Comparative retrospective study on the validity of point-of-care testing device for massive obstetrical hemorrhage: dry hematology vs thromboelastography

Early recognition of hypofibrinogenemia and prompt initiation of transfusion therapy in patients with massive obstetrical hemorrhage can improve prognosis. There are reports on the usefulness of point-of-care testing, which provides quicker test results compared with fibrinogen measurements using the conventional Clauss method. This study aimed to compare and investigate the diagnostic accuracy of dry hematology and thromboelastography in point-of-care testing for the diagnosis of hypofibrinogenemia. A single-center, retrospective study of 126 massive obstetrical hemorrhage cases with point-of-care testing before treatment was initiated. The correlation of fibrinogen values with the Clauss method and the diagnostic accuracy for hypofibrinogenemia were compared between dry hematology and thromboelastography. Fibrinogen value in dry hematology showed a strong positive correlation with values measured by the Clauss method, and the diagnostic accuracy for hypofibrinogenemia was high, but there were many residuals above 100 mg/dL, and the distribution of these residuals was not uniform. Although thromboelastography cannot be used to directly measure fibrinogen values, maximum amplitude citrated functional fibrinogen, amplitude-10 citrated rapid thromboelastography, and amplitude-10 citrated functional fibrinogen showed a strong positive correlation with fibrinogen values using the Clauss method, and no significant difference in correlation or diagnostic accuracy was observed relative to dry hematology. Dry hematology and thromboelastography were equally accurate in diagnosing hypofibrinogenemia, with results correlating well with fibrinogen values measured by the Clauss method.

Clinical and molecular features of virus-induced acute exacerbations of chronic obstructive pulmonary diseas

Introduction. Inflammation in viral-induced acute exacerbations of chronic obstructive pulmonary disease (COPD) is not studied enough.The aim was to establish molecular pattern of inflammation in viral-induced acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in comparison with bacterial AECOPD and to reveal associations with AECOPD phenotype and subsequent COPD progression.Materials and methods. Subjects hospitalized with acute exacerbations of COPD (AECOPD) of which 60 were viral, 60 were bacterial and 60 were viral-bacterial were recruited to single center prospective (52 weeks) cohort study. Control group – 30 healthy people. COPD were diagnosed previously during stable phase of the disease according to spirographic criteria. Viral AECOPD were confirmed by detection of RNA of influenza A and B, respiratory syncytial virus, rhinovirus or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in sputum or bronchoalveolar lavage fluid (BALF) using reverse transcription-polymerase chain reaction (RT-PCR). Bacterial AECOPD were confirmed by sputum/BALF neutrophilia or elevated blood procalcitonin levels or by detecting bacteria by standard culture method. Plasma concentrations of cytokines, fibrotic markers, enzymes were measured by enzyme-linked immunosorbent assay, plasma fibrinogen – by Clauss method. Complex lung function investigation, Dopplerechocardiography, subsequent AECOPD assessment were done. Kruskal-Wallis and chi-square test were used to compare groups, Cox regression and linear regression – to explore relationships.Results. Viral AECOPD were characterized by highest plasma concentrations of Eosinophilic cationic protein (62,3 (52,4; 71,0) ng/ml)), interleukin-5 (IL-5) (11,3 (8,4; 15,9) pg/ml), fibroblast growth factor-2 (FGF-2) (10,4 (6,2; 14,9) pg/ml), transforming growth factor-β1 (TGF-β1) (922,4 (875,7; 953,8) pg/ml), hyaluronic acid (185,4 (172,8; 196,3) ng/ml), amino-terminal propeptide of type III procollagen (PIIINP) (249,2 (225,1; 263,7) ng/ml), matrix metalloproteinase-1 (MMP-1) (235,2 (208,6; 254,9) pg/ml). Levels of IL-5 during AE COPD was the predictor of FEV1, bronchodilation coefficient, subsequent exacerbations at remote period, fibrinogen was associated with FEV1, PIIINP and FGF-2 with DLco, PaO2, mean pulmonary artery pressure (mPAP), exacerbations, MMP-1 – with mPAP.Conclusions. In virus-induced AECOPD inflammation pattern differed from those in bacterial one and associated with AECOPD phenotype and COPD phenotype at the stable phase.

Stability of coagulation factors in feline fresh frozen plasma intended for transfusion after 1 year of storage.

The most common use of plasma transfusion is for haemostatic purposes, but coagulation factor activities in stored feline plasma are unknown. The concentration and stability of coagulation factors I (fibrinogen), II, V, VII, VIII, IX, X, XI and XII in feline fresh frozen plasma (fFFP) stored for 1 year were studied. Fifty-five units of fFFP were produced from 55 fresh whole-blood donations obtained from indoor healthy blood donor cats. Twenty-one units were stored for <2 weeks (T0) and 34 were stored for 1 year (T1). After the completion of storage, specific coagulation factor activities for factors II, V, VII, VIII, IX, X, XI and XII were tested using modified one-stage activated partial thromboplastin or prothrombin time assays. Fibrinogen was determined using the Clauss method. Significantly decreased activities were observed for factors II (T0: 101.94% ± 19.06%; T1: 73.23% ± 39.06% [P = 0.001]), VII (T0: 102.78% ± 24.69%; T1: 60.08% ± 38.17% [P <0.001]), VIII (T0: 77.52% ± 30.39%; T1: 50.32% ± 23.8% [P = 0.001]), XI (T0: 88.76% ± 22.73%; T1: 66.28% ± 22.2% [P = 0.001]) and XII (T0: 89.50% ± 21.85%; T1: 55.46% ± 23.18% [P <0.001]) when comparing units at time 0 and after 1 year of storage. No significant difference was observed for factors IX (T0: 84.86% ± 29.35%; T1: 71.37% ± 22.23% [P = 0.064]) and X (T0: 96.24% ± 25.1%; T1: 83.91% ± 49.54% [P = 0.236]). Unexpectedly, a significant increase was observed for factor V (T0: 71.94% ± 24.14%; T1: 97.89% ± 62.33%; P = 0.046). Fibrinogen was 2.76 ± 1.09 g/l at T1. Factors VIII, XII and VII had the lowest mean activities after 1 year. Although a decrease in most coagulation factors activities was noted with storage, 1-year-old fFFP was haemostatically active in vitro. The most suitable factors for quality control assessment of fFFP are factors VII and VIII. Approximately 13-20 ml/kg of fFFP is required to administer a minimum of 10 IU/kg coagulation factor activity.

Misdiagnosis of a patient with congenital dysfibrinogenemia: A case report and literature review

BackgroundWe reported a patient with congenital dysfibrinogenemia who was misdiagnosed and reviewed relevant literature, in order to discuss the methods to reduce misdiagnosis.MethodsA 23‐year‐old pregnant woman was found to be with low fibrinogen in antenatal examination at another province teaching hospital, who was misdiagnosed to have hypofibrinogenemia. Fibrinogen infusion or cryoprecipitation was recommended if necessary. The patient came to our hospital for further diagnosis and treatment considering the safety of herself and the fetus. We examined the coagulation function and gene sequencing of the pregnant woman and her family members.ResultsFibrinogen (Clauss method) was significantly reduced in the patient and her mother, while the level of fibrinogen (PT‐derived method) was normal. Thrombin time was prolonged. Heterozygous mutation site was found in exon 2 of the FGA gene, c.104G > A(p.Arg35His).ConclusionWhen the fibrinogen (Clauss method) is significantly reduced and the thrombin time is prolonged, PT‐derived method and the investigation of family coagulation function should be added, which can be used to diagnose and distinguish congenital dysfibrinogenemia from hypofibrinogenemia.