Objective:To explore the clinical value of multi-parameter combined monitoring in guiding low-molecular-weight heparin (LMWH) therapy for intensive care unit (ICU) patients.Methods:A retrospective case-control study was conducted. A total of 381 patients who received LMWH therapy with anti-Ⅹa activity monitoring in the ICU of West China Hospital, Sichuan University between January 31st, 2022, and November 30th, 2023, were enrolled in this study. The cohort comprised 264 males and 117 females, with the age of 58 (48, 71) years old. Clinical data and relevant laboratory parameters were collected, including anti-Ⅹa activity, antithrombin activity (AT), thrombin-antithrombin complex (TAT), plasmin-antiplasmin complex (PIC), conventional coagulation parameters such as activated partial thromboplastin time (APTT), and indicators of hepatic/renal impairment such as alanine aminotransferase (ALT) and creatinine( CREA). Patients were stratified into three groups based on thrombotic event: thrombosis-controlled, progressive thrombosis, and bleeding group. Single-factor and adjusted multifactorial Logistic regression analysis were used to identify independent predictors of anti-xa activity levels.Results:Among 381 patients, thrombosis was controlled in 213 (55.9%) patients, progressed in 81 (21.3%) patients , and bleeding events occurred in 87 (22.8%) patients. The patients whose anti-Ⅹa activity levels lay entirely within the target range(0.2-0.4 IU/ml): Only 35 (16.4%) cases in the thrombosis-controlled group, 16 (19.7%) cases in the progressive thrombosis group, and 16 (18.4%) in the bleeding group. No significant differences in anti-Ⅹ a levels activity among the three groups ( H=1.678, P=0.432). Both single-factor and adjusted multifactorial Logistic regression identified low AT activity as an independent risk factor for failure to achieve target anti-Ⅹ a activity levels (AT nadir, OR=1.031,95% CI 1.016-1.046, P<0.05). Compared with the progressive thrombosis and bleedinggroup, the thrombosis-controlled group exhibited significantly higher proportion of TAT values below the cut-off value ( H=8.519, P=0.014), and a higher proportion of TAT/PIC ratios below the cut-off ( H=15.56, P<0.001). Patients with bleeding demonstrated significantly lower AT activity ( H=14.968, P=0.001), prolonged APTT ( H=6.815, P=0.033), higher ALT ( H=13.774, P=0.001), and higher CREA ( H=14.068, P=0.001) compared with the thrombosis-controlled or progressive thrombosis group. Conclusion:Laboratory monitoring is required for low-molecular-weight heparin (LMWH) therapy in ICU patients. While anti-Ⅹa activity reflects the anticoagulant effect of LMWH, the utility of anti-Ⅹ a activity for predicting thrombotic or hemorrhagic risks in LMWH treated ICU patients is limited. Reductions in TAT levels and TAT/PIC ratios are associated with a lower risk of thrombotic progression. Furthermore, abnormalities in conventional coagulation tests and standard hepatic/renal function parameters occur more frequently in patients experiencing hemorrhagic events.

Objective To prepare in-house coagulation factor Ⅷ(F Ⅷ)inhibitor-positive control material and evaluate its perform-ance.Methods Frozen plasma samples from hemophilia A patients with positive factor Ⅷ inhibitors were pooled,and diluted with Owren's Veronal Buffer(OVB)to 1 BU/mL of the inhibitor concentration in the mixture,then aliquoted and freeze-stored.The homo-geneity and stability of the in-house quality control material were verified,and its suitability was further assessed through intra-laborato-ry reproducibility among different technologists and inter-laboratory comparisons.Results Twenty-one aliquots were randomly tested for homogeneity assessment,yielding an average of 1.05 BU/mL(range 0.9-1.15 BU/mL),with a standard deviation(SD)of 0.083 and coefficient of variation(CV)of 7.90％.The freshly prepared inhibitor-positive control samples contained a concentration of 1.03 BU/mL.After storage at-80℃ for 24 hours,1 week,1 month,2 months,3 months,4 months,5 months,6 months,7 months,8 months,and 9 months,thawed the samples showed relative deviations of 9％,0％,10％,9％,14％,15％,6％,0％,-10％,-5％,and 2％,respectively.The intra-laboratory CV value from different technologists at this center was 7.28％,and the inter-labora-tory CV across different centers was 18.75％.Conclusion The prepared in-house positive control material of Factor Ⅷ inhibitor ex-hibited adequate uniformity and stability.

Objective To prepare in-house coagulation factor Ⅷ(F Ⅷ)inhibitor-positive control material and evaluate its perform-ance.Methods Frozen plasma samples from hemophilia A patients with positive factor Ⅷ inhibitors were pooled,and diluted with Owren's Veronal Buffer(OVB)to 1 BU/mL of the inhibitor concentration in the mixture,then aliquoted and freeze-stored.The homo-geneity and stability of the in-house quality control material were verified,and its suitability was further assessed through intra-laborato-ry reproducibility among different technologists and inter-laboratory comparisons.Results Twenty-one aliquots were randomly tested for homogeneity assessment,yielding an average of 1.05 BU/mL(range 0.9-1.15 BU/mL),with a standard deviation(SD)of 0.083 and coefficient of variation(CV)of 7.90％.The freshly prepared inhibitor-positive control samples contained a concentration of 1.03 BU/mL.After storage at-80℃ for 24 hours,1 week,1 month,2 months,3 months,4 months,5 months,6 months,7 months,8 months,and 9 months,thawed the samples showed relative deviations of 9％,0％,10％,9％,14％,15％,6％,0％,-10％,-5％,and 2％,respectively.The intra-laboratory CV value from different technologists at this center was 7.28％,and the inter-labora-tory CV across different centers was 18.75％.Conclusion The prepared in-house positive control material of Factor Ⅷ inhibitor ex-hibited adequate uniformity and stability.

Objective:To explore the clinical value of multi-parameter combined monitoring in guiding low-molecular-weight heparin (LMWH) therapy for intensive care unit (ICU) patients.Methods:A retrospective case-control study was conducted. A total of 381 patients who received LMWH therapy with anti-Ⅹa activity monitoring in the ICU of West China Hospital, Sichuan University between January 31st, 2022, and November 30th, 2023, were enrolled in this study. The cohort comprised 264 males and 117 females, with the age of 58 (48, 71) years old. Clinical data and relevant laboratory parameters were collected, including anti-Ⅹa activity, antithrombin activity (AT), thrombin-antithrombin complex (TAT), plasmin-antiplasmin complex (PIC), conventional coagulation parameters such as activated partial thromboplastin time (APTT), and indicators of hepatic/renal impairment such as alanine aminotransferase (ALT) and creatinine( CREA). Patients were stratified into three groups based on thrombotic event: thrombosis-controlled, progressive thrombosis, and bleeding group. Single-factor and adjusted multifactorial Logistic regression analysis were used to identify independent predictors of anti-xa activity levels.Results:Among 381 patients, thrombosis was controlled in 213 (55.9%) patients, progressed in 81 (21.3%) patients , and bleeding events occurred in 87 (22.8%) patients. The patients whose anti-Ⅹa activity levels lay entirely within the target range(0.2-0.4 IU/ml): Only 35 (16.4%) cases in the thrombosis-controlled group, 16 (19.7%) cases in the progressive thrombosis group, and 16 (18.4%) in the bleeding group. No significant differences in anti-Ⅹ a levels activity among the three groups ( H=1.678, P=0.432). Both single-factor and adjusted multifactorial Logistic regression identified low AT activity as an independent risk factor for failure to achieve target anti-Ⅹ a activity levels (AT nadir, OR=1.031,95% CI 1.016-1.046, P<0.05). Compared with the progressive thrombosis and bleedinggroup, the thrombosis-controlled group exhibited significantly higher proportion of TAT values below the cut-off value ( H=8.519, P=0.014), and a higher proportion of TAT/PIC ratios below the cut-off ( H=15.56, P<0.001). Patients with bleeding demonstrated significantly lower AT activity ( H=14.968, P=0.001), prolonged APTT ( H=6.815, P=0.033), higher ALT ( H=13.774, P=0.001), and higher CREA ( H=14.068, P=0.001) compared with the thrombosis-controlled or progressive thrombosis group. Conclusion:Laboratory monitoring is required for low-molecular-weight heparin (LMWH) therapy in ICU patients. While anti-Ⅹa activity reflects the anticoagulant effect of LMWH, the utility of anti-Ⅹ a activity for predicting thrombotic or hemorrhagic risks in LMWH treated ICU patients is limited. Reductions in TAT levels and TAT/PIC ratios are associated with a lower risk of thrombotic progression. Furthermore, abnormalities in conventional coagulation tests and standard hepatic/renal function parameters occur more frequently in patients experiencing hemorrhagic events.

Objective:To explore solutions to the "grey zone" of activated partial thromboplastin time (APTT) mixing study, and establish the clinical application pathway of it.Methods:Patients treated in West China Hospital of Sichuan University from January 1, 2018, to December 31, 2019, with a prolonged APTT were included in this study. The ROC curve was used to analyze the"cut-off"of different methods and explore solutions to the "grey zone" by combination of the 1∶1 and 4∶1 mixing study. Similar samples from January 1, 2020 to December 31, 2020 were included to verify the diagnostic efficiency of the clinical application pathway.Results:The traditional Rosner index criterion had a low diagnostic accuracy in differentiating factor deficiencies from inhibitors. A total of 49 cases (15%) in the establishment group and validation group were located in the "grey zone". The optimal cut-off value of the Rosner index in our 1∶1 mixing study for determining factor deficiency was 5.0%, and inhibitor was 9.1%. The sample between 5.0% and 9.0% needed 4∶1 mixing studies, which could significantly improve the detection sensitivity of inhibitors. The percentage of extended time after incubation-P (1∶1 mixing>10.8% and 4∶1 mixing>13.5%) was better than the traditional criterion mentioned by"consensus"in determining whether the inhibitor was time-dependent. The sensitivity, specificity, positive predictive value and negative predictive value of combined the 1∶1 and 4∶1 mixing study in differentiating factor deficiencies from inhibitors all attained more than 90%. Only 7% (3/43)of inhibitors were incorrectly classified into the factor deficiency group by the combination, which was 20.9% (9/43) by traditional criterion. The specificity for detecting time-dependent inhibitor was increased from 54.2% to 100%, and accuracy was increased from 63.3% to 97.4%.Conclusions:The combination of 1∶1 and 4∶1 mixing study can better resolve the "grey zone". The established clinical application pathway is beneficial for the further promotion and clinical application of APTT mixing study.

Objective:To establish autoverification rules for coagulation tests in multicenter cooperative units, in order to reduce workload for manual review of suspected results and shorten turnaround time (TAT) of test reports, while ensure the accuracy of results.Methods:A total of 14 394 blood samples were collected from fourteen hospitals during December 2019 to March 2020. These samples included: Rules Establishment Group 11 230 cases, including 1 182 cases for Delta check rules; Rules Validation Group 3 164 cases, including 487cases for Delta check; Clinical Application Trial Group 77 269 cases. Samples were analyzed for coagulation tests using Sysmex CS series automatic coagulation analyzers, and the clinical information, instrument parameters, test results, clinical diagnosis, medication history of anticoagulant and other relative results such as HCT, TG, TBIL, DBIL were summarized; on the basis of historical data, the 2.5 and 97.5 percentile of all data arranged from low to high were initially accumulated; on the basis of clinical suggestions, critical values and specific drug use as well as relative guidelines, autoverification rules and limits were established.The rules were then input into middleware, in which Stage I/Stage II validation was done. Positive coincidence, negative coincidence, false negative, false positive, autoverification pass rate, passing accuracy (coincidence of autoverification and manual verification) were calculated. Autoverification rules underwent trial application in coagulation results reports.Results:(1) The autoverification algorisms involve 33 rules regarding PT/INR, APTT, FBG, D-dimer, FDP,Delta check, reaction curve and sample abnormalities; (2)Autoverification Establishment Group showed autoverification pass rate was 68.42% (7 684/11 230), the false negative rate was 0%(0/11230), coincidence of autoverification and manual verification was 98.51%(11 063/11 230), in which positive coincidence and negative coincidence were respectively 30.09% (3 379/11 230) and 68.42%(7 684/11 230); Autoverification Validation Group showed autoverification pass rate was 60.37%(1 910/3 164), the false negative rate was 0%(0/11 230), coincidence of autoverification and manual verification was 97.79%(3 094/3 164), in which positive coincidence and negative coincidence were respectively 37.42%(1 184/3 164) and 60.37%(1 910/3 164); (3) Trialed implementation of these autoverification rules on 77 269 coagulation samples showed that the average TAT shortened by 8.5 min-83.1 min.Conclusions:This study established 33 autoverification rules in coagulation tests. Validation showedthese rules could ensure test quality while shortening TAT and lighten manual workload.