Impact of quality control matrix effect: application to the calculation of uncertainty of measurement in one-stage clotting factor VIII assay

Sobas, Frédéric; Benattar, Norbert; Bellisario, Audrey; Marin, Sylvie; Nougier, Christophe; Lienhart, Anne; Négrier, Claude

doi:10.1097/mbc.0b013e328338dbd3

Cited by 8 publications

(6 citation statements)

References 11 publications

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“…Because these tests are complex biological assays, despite being fully automated, we regard these to be realistic and satisfactory assessments of the random test error. These estimates for within-and betweenrun CVs agree with publications using automated methods and commercial reagents for FVIII:C-1 30,31 and FVIII:C-chr. 32 However, as a simplified example, this means that a reported FVIII:C-1 result of 40 IU/dL has an estimated SD ¼ 2.0 and, therefore, a 95% confidence interval (CI) of 36 to 44 IU/dL.…”

Section: Fviii:c Assay Quality Assessmentsupporting

confidence: 86%

Diagnostic Testing for Mild Hemophilia A in Patients with Discrepant One-Stage, Two-Stage, and Chromogenic Factor VIII:C Assays

Duncan

Rodgers

McRae

2013

Semin Thromb Hemost

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In recent years, there has been greater awareness among hemostasis scientists and clinicians that factor VIII coagulant activity (FVIII:C) measured in certain patients with mild hemophilia A can show different results depending on the assay system. A subgroup of mild hemophilia families have a method-related discrepancy in FVIII:C results, whereby the one-stage clotting assay (FVIII:C-1) is significantly higher than the two-stage clotting assay (FVIII:C-2) or the chromogenic assay (FVIII:C-chr). To identify such patients, the routine laboratory can use automated procedures for the FVIII:C-chr to replace the complex, manual FVIII:C-2 method. Laboratories must employ appropriate quality management to ensure accurate and precise results, especially in the abnormal range. This discrepant phenotype of hemophilia A is seen in up to 40% of mild hemophilia A cases and represents a clinically significant bleeding disorder. A small proportion of these cases have FVIII:C-1 within the normal range and risk a missed diagnosis if the FVIII:C-chr is unavailable. Other patients may be mismanaged if FVIII:C-1 gives an overestimate of FVIII:C and their bleeding risk is consequently underestimated. Affected family members in the discrepant group of patients have a limited range of FVIII (F8) gene missense mutations, causing alterations of the structure of the A1, A2, or A3 domains of FVIII. Therefore, both FVIII:C-chr and F8 gene mutation analysis are recommended to confirm the diagnosis of mild hemophilia A and assist with decisions about the patient's phenotype.

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Section: Fviii:c Assay Quality Assessmentsupporting

confidence: 86%

Diagnostic Testing for Mild Hemophilia A in Patients with Discrepant One-Stage, Two-Stage, and Chromogenic Factor VIII:C Assays

Duncan

Rodgers

McRae

2013

Semin Thromb Hemost

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“…The uncertainty of measurement (UM) was obtained as recently described [10] after calculating long-term CV (LCV) and bias (B) values according to Meijer et al [9] and with respect to the exact final concentrations measured with CSA/PS after freezing samples at )80°C for 48 h in the Lille Haemostasis department [4].…”

Section: Discussionmentioning

confidence: 99%

“…The aim of the study presented here was to evaluate the impact of the ReFacto AF Laboratory Standard in the measurement of FVIII:C levels in mock plasma ReFacto AF ® samples by OSA and CSA. As European laboratories are also required to implement the ISO 15 189 standard, the inter‐method discrepancy was also evaluated by assessing the uncertainty of measurement (UM) [9,10].…”

Section: Introductionmentioning

confidence: 99%

The use of the new ReFacto AF Laboratory Standard allows reliable measurement of FVIII:C levels in ReFacto AF mock plasma samples by a one‐stage clotting assay

et al. 2011

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Factor VIII coagulant (FVIII:C) levels measured in patients receiving ReFacto® (B-domain-deleted recombinant FVIII) using chromogenic substrate assay (CSA) and one-stage clotting assay (OSA) have frequently shown discrepancies, and the use of the ReFacto Laboratory Standard (RLS) has therefore been recommended to minimize these differences. The potency of ReFacto AF®, the albumin-free successor of ReFacto®, is determined using CSA for the titration of vials, and a new standard (RLS-AF) was developed to measure its biological efficacy using OSA. This multicentre study therefore evaluated the efficacy of this new RLS in minimizing differences between OSA and CSA when measuring FVIII:C levels in plasma. Mock plasma samples were prepared by diluting ReFacto AF® in FVIII-deficient plasma to obtain four concentrations ranging from 15 to 90 IU dL⁻¹ . FVIII:C levels were then measured in six laboratories on four separate days using three different procedures, i.e. OSA with a plasma standard (PS) as reference, OSA with RLS-AF and CSA with PS. The inter-centre standard deviation ranged from 1.4 to 5.5 IU dL⁻¹. However, FVIII:C levels measured with OSA were closer to the expected values when RLS-AF was used. In addition, the uncertainty of measurement, reflecting the inter-method discrepancy was greatly reduced when RLS-AF was employed in OSA (15%) in place of PS (33%). This study demonstrates that the OSA performed with RLS-AF to establish calibration curves provides a valuable alternative to CSA to measure FVIII:C in ReFacto-AF-treated patients.

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“…The individual coagulation factor assays performed prospectively were Factor VIII (EV2030‐1), von Willebrand factor (vWF; EV2030‐7), protein C (EP2312‐1), antithrombin III (AT; EA3301‐1), fibrinogen (EF2040‐1), tissue factor level (TF; ET1002‐1), plasminogen activator inhibitor (PAI‐1) and tPA (EP1105‐1) using a commercially available ELISA AssayMax™ ELISA (Assaypro, St. Charles, MO) . All coagulation assays, TEG and SCTs were done within 12 hours of presentation and repeated at days 3 and 7, or when the patient met the study criteria for suspected or proven sepsis.…”

Section: Methodsmentioning

confidence: 99%

“…18 Maximum amplitude (MA, 40-50 mm) is the maximal distance between the two diverging branches, reflect- The individual coagulation factor assays performed prospectively were Factor VIII (EV2030-1), von Willebrand factor (vWF; EV2030-7), protein C (EP2312-1), antithrombin III (AT; EA3301-1), fibrinogen (EF2040-1), tissue factor level (TF; ET1002-1), plasminogen activator inhibitor (PAI-1) and tPA (EP1105-1) using a commercially available ELISA AssayMax™ ELISA (Assaypro, St. Charles, MO). [21][22][23][24] All coagulation assays, TEG and SCTs were done within 12 hours of presentation and repeated at days 3 and 7, or when the patient met the study criteria for suspected or proven sepsis. The coagulation assays of a patient at day 0 served as control, for evaluating the effect of SIRS/sepsis on subsequent testing of haemostasis in ACLF.…”

Section: Methodsmentioning

confidence: 99%

Coagulation failure is associated with bleeding events and clinical outcome during systemic inflammatory response and sepsis in acute‐on‐chronic liver failure: An observational cohort study

Premkumar

Saxena

Rangegowda

et al. 2019

Liver International

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Background Patients with acute‐on‐chronic liver failure (ACLF) have coagulation failure in the setting of systemic inflammatory syndrome (SIRS), sepsis and extra‐hepatic organ failures. Methods Consecutive ACLF patients without sepsis at baseline were assessed at days 0, 3 and 7 with thromboelastography (TEG) and specific assays (Factor VIII, von Willebrand factor [vWF], protein C and antithrombin III [ATIII]) and followed for development of sepsis, bleeding and outcome. Results Of 243 patients, 114 (63% ethanol related; mean age 44.3 ± 11.7 years; 90% male) were recruited. SIRS was noted in 39 (34.2%), 45 (39.5%) and 46 (40%) patients at days 0, 3 and 7 and sepsis in 28 (24%) and 52 (56.1%) patients at days 3 and 7 respectively. The 28‐ and 90‐day survivals were 62% and 51% respectively. A hypocoagulable TEG at baseline was a predictor of bleeding (hazard ratio [HR] 2.1; CI 1.6‐4.9; P = 0.050) and mortality (HR 1.9; CI 1.3‐7.9; P = 0.043). ACLF patients had increased Factor VIII, vWF, tissue factor levels and tissue plasminogen activator (tPA) activity with reduced protein C and ATIII. Coagulation parameters like Coagulation Index (HR 2.1; CI 1.1‐4.5; P = 0.044),clot lysis (HR 3.2; CI 1.9‐3.4; P = 0.033), low protein C < 30% (HR 2.1; CI 1.5‐2.8; P = 0.017), ATIII (HR 1.4; CI 1.7‐3.1; P = 0.052) and tPA (HR 1.5; CI 1.1‐2.4; P = 0.052) were predictors of mortality at day 28. Protein C activity <30% (HR 1.3; CI 1.0‐2.9; P = 0.042) and tPA >20 ng/mL (HR 1.2; CI 1.1‐2.1; P = 0.040) predicted mortality when adjusted for age, gender and baseline MELD. Conclusions Dynamic coagulation derangements, measured by TEG, determine the likelihood of bleeding and mortality in ACLF.

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Impact of quality control matrix effect: application to the calculation of uncertainty of measurement in one-stage clotting factor VIII assay

Cited by 8 publications

References 11 publications

Diagnostic Testing for Mild Hemophilia A in Patients with Discrepant One-Stage, Two-Stage, and Chromogenic Factor VIII:C Assays

Diagnostic Testing for Mild Hemophilia A in Patients with Discrepant One-Stage, Two-Stage, and Chromogenic Factor VIII:C Assays

The use of the new ReFacto AF Laboratory Standard allows reliable measurement of FVIII:C levels in ReFacto AF mock plasma samples by a one‐stage clotting assay

Coagulation failure is associated with bleeding events and clinical outcome during systemic inflammatory response and sepsis in acute‐on‐chronic liver failure: An observational cohort study

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