High Prevalence of Acquired Thrombophilia Without Prognosis Value in Patients With Coronavirus Disease 2019.

Background Recent literature reports a strong thrombotic tendency in patients hospitalized for a coronavirus disease 2019 (COVID-19) infection. This characteristic is unusual and seems specific to COVID-19 infections, especially in their severe form. Viral infections can trigger acquired thrombophilia, which can then lead to thrombotic complications. We investigate for the presence of acquired thrombophilia, which could participate in this phenomenon, and report its prevalence. We also wonder if these thrombophilias participate in the bad prognosis of severe COVID-19 infections. Methods and Results In 89 consecutive patients hospitalized for COVID-19 infection, we found a 20% prevalence of PS (protein S) deficiency and a high (ie, 72%) prevalence of antiphospholipid antibodies: mainly lupus anticoagulant. The presence of PS deficiency or antiphospholipid antibodies was not linked with a prolonged activated partial thromboplastin time nor with D-dimer, fibrinogen, or CRP (C-reactive protein) concentrations. These coagulation abnormalities are also not linked with thrombotic clinical events occurring during hospitalization nor with mortality. Conclusions We assess a high prevalence of positive tests detecting thrombophilia in COVID-19 infections. However, in our series, these acquired thrombophilias are not correlated with the severity of the disease nor with the occurrence of thrombotic events. Albeit the strong thrombotic tendency in COVID-19 infections, the presence of frequent acquired thrombophilia may be part of the inflammation storm of COVID-19 and should not systematically modify our strategy on prophylactic anticoagulant treatment, which is already revised upwards in this pathological condition. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT04335162.

Monitoring unfractionated heparin therapy. 4 hour-stability of anti-Xa activity in unspun citrated tubes.

Current guidelines recommend performing laboratory tests aimed at monitoring unfractionated heparin (UFH) treatments within a delay not exceeding 1 to 2 h(s) after sampling when blood is collected into citrated tubes. As such a short delay could be an issue, we evaluated the potential impact of longer delays. For that purpose, two citrated tubes were obtained from patients on UFH: one was centrifuged and tested for anti-Xa activity and aPTT within 1 h after collection (T1 h) and one was stored for 4 h at room temperature (T4 h) before being processed. A total of 123 paired tubes were investigated. Anti-Xa activity was significantly lower at T4 h than at T1 h, with a mean bias, calculated according to Bland-Altman, of 0.05 IU/mL. Considering 0.30 to 0.70 IU/mL as the therapeutic range, there were 12 cases of discrepant test results (9.8%). Most of them being around the lower limit of the therapeutic range had no impact on patients' management. APTT was significantly shortened (p < 0.0001) at T4 h vs. T1 h, with a mean bias of -7.9 s. Considering anti-Xa correlated aPTT therapeutic range, 29 cases of discrepant test results (23.6%) were found, 10% would have induce dosage changes. The concordance between anti-Xa activities measured at T4 h and T1 h was excellent (kappa = 0.813) and good for aPTT (kappa = 0.661). In conclusion, extending the delay between blood collection and measurement of tests prescribed for monitoring UFH therapy up to 4 h was found to lead to a systematic reduction in both anti-Xa activity and aPTT in unspun citrated tubes. As changes at T4 h were limited and had few clinically relevance than the ones observed with aPTT testing, a 4 h-delay was found to be acceptable for anti-Xa activity. The maximum delay for aPTT should remain around 1-2 h as changes were more relevant.

Evaluation and performance characteristics of the Q Hemostasis Analyzer, an automated coagulation analyzer.

The Q Hemostasis Analyzer (Grifols, Barcelona, Spain) is a fully-automated random-access multiparameter analyzer, designed to perform coagulation, chromogenic and immunologic assays. It is equipped with a cap-piercing system. The instrument was evaluated in a hemostasis laboratory of a University Hospital with respect to its technical features in the determination of coagulation i.e. prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time, fibrinogen and single coagulation factors V (FV) and VIII (FVIII), chromogenic [antithrombin (AT) and protein C activity] and immunologic assays [von Willebrand factor antigen (vWF:Ag) concentration], using reagents from the analyzer manufacturer. Total precision (evaluated as the coefficient of variation) was below 6% for most parameters both in normal and in pathological ranges, except for FV, FVIII, AT and vWF:Ag both in the normal and pathological samples. No carryover was detected in alternating aPTT measurement in a pool of normal plasma samples and in the same pool spiked with unfractionated heparin (>1.5 IU/mL). The effective throughput was 154 PT, 66 PT/aPTT, 42 PT/aPTT/fibrinogen, and 38 PT/aPTT/AT per hour, leading to 154 to 114 tests performed per hour, depending of the tested panel. Test results obtained on the Q Hemostasis Analyzer were well correlated with those obtained on the ACL TOP analyzer (Instrumentation Laboratory), with r between 0.862 and 0.989. In conclusion, routine coagulation testing can be performed on the Q Hemostasis Analyzer with satisfactory precision and the same apply to more specialized and specific tests.

Evaluation and performance characteristics of the automated coagulation analyzer ACL TOP.

INTRODUCTION: The ACL TOP is a fully-automated random-access multiparameter coagulation analyzer equipped with a photo-optical clot-detection unit. It is designed to perform coagulation, chromogenic and immunologic assays with continuous loading capabilities for samples, reagents and disposables. MATERIALS AND METHODS: The instrument was evaluated in a coagulation laboratory of a university hospital with respect to its technical features in the determination of routine coagulation (prothrombin time, activated partial thromboplastin time, fibrinogen and single coagulation factor levels), chromogenic (anti-activated factor X, antithrombin and protein C activities) and immunologic assays (free protein S and von Willebrand factor antigen concentrations). RESULTS: Using fresh and lyophilized plasma samples, the intra-assay and inter-assay coefficients of variation were below 5% for most of the parameters both in the normal and in the pathological ranges. For clotting assays performed at 671 nm, no significant interference could be demonstrated with hemolytic, icteric and lipemic samples as demonstrated by results similar to those obtained using a mechanical clot-detection-based analyzer (STAR). No sample carryover was detected in measuring alternatively heparinized (1.0 IU/mL unfractionated heparin) and normal plasma samples. The results of the different coagulation, chromogenic and immunologic assays obtained on the ACL TOP were well correlated with those obtained on the STAR analyzer with the correlation coefficient (r) in the range from 0.876 to 0.990. CONCLUSIONS: Our results demonstrated that using the ACL TOP analyzer, routine hemostasis testing can be performed with satisfactory precision and the same applied to more specialized and specific tests such as single factor activity or antigen concentration.

Evaluation of the automated coagulation analyzer Sysmex CA-7000.

The Sysmex CA-7000 is a fully automated multiparameter hemostasis analyzer equipped with a photo-optical clot detection unit and a cap-piercing system. It is designed to perform coagulation tests as well as chromogenic and immunologic assays. It was evaluated in a coagulation laboratory of a university hospital with respect to its technical characteristics in the determination of routine coagulation (prothrombin time, activated partial thromboplastin time, fibrinogen and single coagulation factors), chromogenic (antithrombin, and anti-FXa activity) and immunologic assays (von Willebrand factor). The intra-assay and inter-assay coefficients of variation (CV) were below 5% for most parameters both in the normal and in the pathological range (exceptions: intra-assay CV=5.2% for the fibrinogen and 5.1% for antithrombin in the low range of concentrations; and inter-assay CV=5.7% and 7.2% for clotting factors V and VII levels in the normal ranges, and in the range from 6.1% to 7.8% for anti-FXa activity). No significant interference could be demonstrated with hemolytic and icteric samples as demonstrated by results similar to those obtained using a mechanical clot detection-based analyzer (STAR). No carryover was detected in alternating measurements of heparinized (1.0 IU/mL unfractionated heparin) and normal plasma samples. The results of the different coagulation, chromogenic and immunologic assays obtained with the CA-7000 analyzer were well correlated with those obtained on the STAR analyzer (r in the range from 0.885 to 0.990). Our results demonstrated that using the CA-7000 analyzer, routine coagulation testing can be performed with satisfactory precision and the same applied to more specialized and specific tests such as single factor activity or antigen concentration.