Reference Intervals of Routine Coagulation Assays During the Pregnancy and Puerperium Period.

BACKGROUND: Significant changes occur in the coagulation and fibrinolytic systems during pregnancy and puerperium in the plasma levels. However, reference ranges based on healthy people are not optimal for informing clinical decisions during the pregnancy and puerperium. Therefore, it is essential to explore coagulation assays' reference ranges during the pregnancy and puerperium. METHODS: Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (Fib.), and D-dimer were all measured according to the manufacturer's specifications and laboratory standard operating procedure of the STA-R evolution coagulation analyzer. A total of 11,601 women were enrolled in this study. RESULTS: The reference ranges for PT, APTT, TT, Fib., and D-dimer in nonpregnancy period were 10.87-13.76 s, 29.22-44.61 s, 15.39-20.15 s, 1.59-3.97 g/l, and 0-0.56 mg/l, respectively. In early-pregnancy period, the ranges were 11.14-14.07 s, 29.97-44.69 s, 14.92-19.03 s, 1.98-4.13 g/l, and 0-1.67 mg/l, respectively. In midpregnancy period, the ranges were 9.98-12.84 s, 28.53-40.70 s, 13.51-19.82 s, 2.63-5.19 g/l, and 0-2.81 mg/l, respectively. In late-pregnancy period, the ranges were 9.48-12.58 s, 28.61-40.80 s, 14.10-19.61 s, 2.80-5.56 g/l, and 0-27.08 mg/l, respectively. In puerperium period, the ranges were 10.85-13.72 s, 30.51-43.02 s, 15.31-19.64 s, 1.14-5.07 g/l, and 1.27-4.85 mg/l, respectively. CONCLUSION: We presented reference intervals for coagulation assays from the nonpregnancy to puerperium period that can be adopted in other laboratories after further validation.

Performance evaluation of a new Stago® automated haemostasis analyser: The STA R Max® 2.

INTRODUCTION: The STA R Max® 2 is a new coagulation analyser developed by Diagnostica Stago, able to perform clotting, chromogenic and immuno-turbidimetric tests. A pre-analytical module build into the cap-piercing needle performs the sample integrity verification (sample tube filling and measurement of haemolysis, icterus, lipaemia). The STA R Max® 2 analyser incorporates an accreditation program tools to assist technical validation of the analyser. We assessed the analytical performance of the STA R Max® 2. MATERIALS AND METHODS: The following tests were assessed: prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, factor V (FV), antithrombin (AT), D-dimers (DDI) and von Willebrand factor antigen. The assay precisions were assessed using fresh plasma samples or internal quality controls. An inter-analyser comparison was performed with a STA-R Evolution® analyser or, for the FV, with a BCS® XP System. Haemolysis and icterus detection were also verified. RESULTS: For the intra-assay precision, the coefficients of variation (CV%) were all less than 5% and for DDI, the standard deviation (SD) was less than 0.1. For the inter-assay study, all CV% were less than 5%, with the exception of FV and AT (FV: 6.68% and 5.27%; AT: 7% and 12.14% for normal and pathological values, respectively). SD was less than 0.1 for DDI. The inter-analyser comparison demonstrated good results. Haemolysis and icterus were detected correctly for all our assessed samples. CONCLUSION: According to our methods validation's recommendations, the results demonstrated a good technical and analytical performance of the STA R Max® 2 analysers for the tests assessed.

Evaluation of an automated algorithm for interpretation of lupus anticoagulant testing.

INTRODUCTION: Lupus anticoagulant (LAC) testing is a multistep procedure including screening, mixing, and confirmation tests. STA Coag Expert is a software module for STA R Max and STA Compact Max analyzers which includes an on-demand LAC algorithm, based on ISTH guidelines, for automatic interpretation, calculation, and launch of assays in LAC interpretation ("Stago coag algorithm"). MATERIALS AND METHODS: One hundred ninety four patient samples were analyzed in parallel and interpreted manually and automatically by LAC algorithms. LAC algorithms use identical flowcharts and cutoff values as in daily practice. Differently, it only uses index of circulating anticoagulant (ICA), whereas in routine also normalized ratios were assessed for interpretation of mixing tests. Interpretation of dRVVT and aPTT pathways and final conclusions were compared between both approaches. RESULTS: Compared to routine interpretation, LAC algorithm showed a sensitivity of 94% and a specificity of 100% for LAC detection, when discrepancies due to measured clotting times between both analyzers were excluded. Three false negatives were due to different interpretation of dRVVT mixing test. Discrepancies in interpretation of the aPTT mixing test (n = 11) did not result in discrepant final LAC result, all having negative confirmation tests. No false positives were observed. With LAC algorithm, hands-on time reduced from 200 to 80 minutes. CONCLUSION: The LAC algorithm of the STA Coag Expert shows good comparability to the manual interpretation of LAC and may be used to assist laboratories in automatic launching of additional tests and in interpretation of LAC according to ISTH guidelines. This way the STA Coag Expert LAC algorithm may improve interlaboratory and STA comparability of LAC results.

[Evaluation of the coagulometer STA R Max® (Stago) for routine coagulation parameters]. / Évaluation des performances de l'automate STA R Max® (Stago) pour les paramètres d'hémostase de routine.

The STA R Max® is a fully automated multiparameter coagulometer using clotting (viscosity-based detection system), chromogenic and immunologic assays. STA R Max® is equipped with an innovative software (STA Coag Expert®) designed to assist laboratory in accreditation. The aim of this study was to evaluate its performances for the certification according to ISO 15189 quality standard in the haemostasis unit of our university hospital. The following tests were evaluated: prothrombin time (PT), activated partial thromboplastin time (aPTT), kaolin cephalin clotting time (KCCT), fibrinogen, anti-Xa assay and D-dimers. In normal and pathological range, the intra-assay coefficients of variation (CV) for PT, aPTT, KCCT and fibrinogen were below 4.0%. Intra-assay CV was of 4.0% for the anti-Xa assay and intra-assay CV was of 7.9% for D-dimers. Inter-assay CV were below 5.0% for PT, aPPT, KCCT and fibrinogen, 14.9% for anti-Xa assay and 8.6% for D-dimers. The interlaboratory comparisons were below 8.7% for PT, aPPT and KCCT, 5.0% for fibrinogen and 15.5% for anti-Xa assay. All results were acceptable according to suitable CV established by GFHT and the provider. The concordance between all coagulometers was excellent, with correlation coefficient close to 1 (0.99 for all parameters except for aPPT which was 0.98) calculated thanks to an intra-class correlation study. In conclusion, the STA R Max® analyser is suitable for haemostasis laboratories and facilitates certification of a laboratory.

Validation of the Sysmex CS5100 coagulation analyzer and comparison to the Stago STA-R analyzer for routine coagulation parameters.

INTRODUCTION: The CS5100 analyzer (Sysmex) was validated for the determination of routine coagulation parameters. This fully automated coagulation analyzer uses multiple wavelength technology to perform coagulation (e.g., activated partial thromboplastin time - APTT, prothrombin time - PT, fibrinogen - FBG), chromogenic (e.g., antithrombin - AT) and immunological (e.g., D-dimers - DDi) assays. METHODS: A comparison with the currently used STA-R Evolution (Stago) was performed. Validation and verification of reference values of the CS5100 was performed in accordance to CLSI guidelines (H57-A, H47-A2, and C28-A3). RESULTS: As a different detection system and reagents were used, significant differences were observed (e.g. APTT). The within-day and between-day imprecision, accuracy and total error were all acceptable. The reference values defined by the manufacturer could be used except for APTT. In our settings, the therapeutic anti-Xa range of 0.3-0.7 IU/mL corresponded to an APTT range of 60-100 s (Dade actin FS reagent). The APTT reagent showed factor sensitivities between 46 and 72% for FVIII, IX, XI and XII while the PT reagent showed sensitivities between 34 and 52% for FII, FV, FXII, and FX. CONCLUSION: In conclusion, the CS5100 instrument is suitable for the determination of the APTT, PT, FBG, DDi and AT in routine analysis.