scholarly journals Potency estimates for recombinant factor IX in the one-stage clotting assay are influenced by more than just the choice of activated partial thromboplastin time reagent

Haemophilia ◽  
2018 ◽  
Vol 24 (5) ◽  
pp. e363-e368 ◽  
Author(s):  
Helen V. Wilmot ◽  
Elaine Gray
Keyword(s):  
Partial Thromboplastin Time ◽  
Activated Partial Thromboplastin Time ◽  
Factor Ix ◽  
One Stage ◽  
Recombinant Factor Ix ◽  
The One

scholarly journals Comparative field study: impact of laboratory assay variability on the assessment of recombinant factor IX Fc fusion protein (rFIXFc) activity

2014 ◽  
Vol 112 (11) ◽  
pp. 932-940 ◽  
Author(s):  
Yang Buyue ◽  
Sara Bardan ◽  
Robert Peters ◽  
Haiyan Jiang ◽  
George Kamphaus ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Field Study ◽  
Factor Ix ◽  
One Stage ◽  
Chromogenic Assay ◽  
Fc Fusion Protein ◽  
Recombinant Factor Ix ◽  
Assay Methods ◽  
The Mean ◽  
The One

SummaryDue to variability in the one-stage clotting assay, the performance of new factor IX (FIX) products should be assessed in this assay. The objective of this field study was to evaluate the accuracy of measuring recombinant FIX Fc fusion protein (rFIXFc) activity in clinical haemostasis laboratories using the one-stage clotting assay. Human haemophilic donor plasma was spiked with rFIXFc or BeneFIX® at 0.80, 0.20, or 0.05 IU/ml based on label potency. Laboratories tested blinded samples using their routine one-stage assay and in-house FIX plasma standard. The mean spike recoveries for BeneFIX (n=30 laboratories) were 121 %, 144 %, and 168 % of expected at nominal 0.80, 0.20, and 0.05 IU/ml concentrations, respectively. Corresponding rFIXFc spike recoveries were 88 %, 107 %, and 132 % of expected, respectively. All BeneFIX concentrations were consistently overestimated by most laboratories. rFIXFc activity was reagent-dependent; ellagic acid and silica gave higher values than kaolin, which underestimated rFIXFc. BeneFIX demonstrated significantly reduced chromogenic assay activity relative to one-stage assay results and nominal activity, while rFIXFc activity was close to nominal activity at three concentrations with better dilution linearity than the typical one-stage assay. In conclusion, laboratory- and reagent-specific assay variabilities were revealed, with progressively higher variability at lower FIX concentrations. Non-parallelism against the FIX plasma standard was observed in all one-stage assays with rFIXFc and BeneFIX, leading to significant overestimation of FIX activity at lower levels and generally high inter-laboratory variability. Compared to the accuracy currently achieved in clinical laboratories when measuring other rFIX products, most laboratories measured rFIXFc activity with acceptable accuracy and reliability using routine one-stage assay methods and commercially available plasma standards.

Performances of an Artificial Reagent for the One-stage Factor IX Assay

1975 ◽  
Vol 33 (03) ◽  
pp. 547-552 ◽  
Author(s):  
L Meunier ◽  
J. P Allain ◽  
D Frommel
Keyword(s):  
Human Plasma ◽  
Factor Ix ◽  
Severe Haemophilia ◽  
Normal Human Plasma ◽  
Haemophilia B ◽  
One Stage ◽  
Normal Human ◽  
The One

SummaryA mixture of adsorbed normal human plasma and chicken plasma was prepared as reagent for factor IX measurement using a one-stage method. The substrate was found to be specific for factor IX. Its performances tested on samples displaying factor IX activity ranging from <l%–2,500% compared favorably with those obtained when using the plasma of severe haemophilia B patients as substrate.

The Formation of Intermediate Product I in a Purified System The Role of Factor IX or of its Precursor and of a Hageman Factor-PTA Fraction

1961 ◽  
Vol 6 (02) ◽  
pp. 224-234 ◽  
Author(s):  
E. T Yin ◽  
F Duckert
Keyword(s):  
Intermediate Product ◽  
Factor Ix ◽  
Assay Method ◽  
Lag Phase ◽  
Factor X ◽  
Haemophilia B ◽  
Hageman Factor ◽  
One Stage ◽  
The One

Summary1. The role of two clot promoting fractions isolated from either plasma or serum is studied in a purified system for the generation of intermediate product I in which the serum is replaced by factor X and the investigated fractions.2. Optimal generation of intermediate product I is possible in the purified system utilizing fractions devoid of factor IX one-stage activity. Prothrombin and thrombin are not necessary in this system.3. The fraction containing factor IX or its precursor, no measurable activity by the one-stage assay method, controls the yield of intermediate product I. No similar fraction can be isolated from haemophilia B plasma or serum.4. The Hageman factor — PTA fraction shortens the lag phase of intermediate product I formation and has no influence on the yield. This fraction can also be prepared from haemophilia B plasma or serum.

In Vitro Thrombogenicity Tests of Factor IX Concentrates

1979 ◽  
Vol 42 (05) ◽  
pp. 1355-1367 ◽  
Author(s):  
C V Prowse ◽  
A Chirnside ◽  
R A Elton
Keyword(s):  
Factor Viii ◽  
Partial Thromboplastin Time ◽  
Generation Time ◽  
Activated Partial Thromboplastin Time ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Factor Viii Inhibitor ◽  
Factor Ixa ◽  
Viii Inhibitor

SummaryVarious factor IX concentrates have been examined in a number of in vitro tests of thrombogenicity. The results suggest that some tests are superfluous as in concentrates with activity in any of these tests activation is revealed by a combination of the non-activated partial thromboplastin time, the thrombin (or Xa) generation time and factor VIII inhibitor bypassing activity tests. Assay of individual coagulant enzymes revealed that most concentrates contained more factor IXa than Xa. However only a small number of concentrates, chiefly those that had been purposefully activated, contained appreciable amounts of either enzyme.

scholarly journals Antiphospholipid Antibodies and Acquired Thrombophilia: A Biological Marker for Recurrent Miscarriage

2021 ◽  
pp. 137-143
Author(s):  
Rania Khogli ELsidig Khogli ◽  
Abdel Rahim Mahmoud Muddathir ◽  
Alaa Eltayeb Omer ◽  
Lienda Bashier Eltayeb
Keyword(s):  
Partial Thromboplastin Time ◽  
Antiphospholipid Antibodies ◽  
Tissue Injury ◽  
Recurrent Miscarriage ◽  
Biological Marker ◽  
Activated Partial Thromboplastin Time ◽  
P Value ◽  
Increased Risk ◽  
The One ◽  
Acquired Thrombophilia

Background: Repeated miscarriage can cause tissue injury can lead to the formation of antibodies to the phospholipids. Recurrent miscarriage (RM) is considering the one of the most common cause of sterility. Which has received more attention in recent years as a result of an increase in the number of reproductive-aged women. Materials and Methods: Plasma samples were tested for antiphospholipid antibodies using ELISA, and platelet count using Sysmex (KX21) Heamatology analyzer and Activated Partial Thromboplastin Time using semi-automated machine (STAGO PT31039352 (for coagulation). Results: The prevalence of Anti phospholipid antibodies (APL) was 30.5% in Sudanese patients with recurrent miscarriage, the prevalence of (Anti phospholipid Antibodies-IgM and IgG) was found to be 23.6% in patients with recurrent miscarriage compared to (Anti phospholipid Antibodies-IgG) was found to be 11.1% ((P value≤0.001), low platelets count (<50×109/l) observed in 10 (13.5%), as well as prolongation of activated partial thromboplastin time (APTT) among studied group were detected among 19 (26.1%). Conclusion: Higher prevalence of antiphospolidids antibodies, and acquired thrombophilia was detected among Sudanese women with recurrent abortion; The findings are concerning because they link an increased risk of thrombosis and a hypercoagulable state lead to recurrent miscarriage in pregnant women.

Recombinant factor IX: discrepancies between one-stage clotting and chromogenic assays

Haemophilia ◽  
2014 ◽  
Vol 20 (6) ◽  
pp. 891-897 ◽  
Author(s):  
H. V. Wilmot ◽  
J. Hogwood ◽  
E. Gray
Keyword(s):  
Factor Ix ◽  
One Stage ◽  
Recombinant Factor Ix

scholarly journals The Pharmacokinetic Properties, Safety and Tolerability of a New Nonacog Alfa (Innonafactor) in Patients with Hemophilia B

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4691-4691 ◽  
Author(s):  
Vladimir Yu. Zorenko ◽  
Georgy Mishin ◽  
Tatiana Severova ◽  
Alexandr Shuster ◽  
Dmitry Kudlay ◽  
...  
Keyword(s):  
Single Dose ◽  
Phase I ◽  
Partial Thromboplastin Time ◽  
Coagulation Factor ◽  
Maximum Tolerated Dose ◽  
Activated Partial Thromboplastin Time ◽  
Factor Ix ◽  
Hemophilia B ◽  
Coagulation Factor Ix ◽  
Pharmacokinetic Properties

Abstract Nonacog alfa is a recombinant factor IX (rFIX) product for hemophilia B, developed by CJSC «GENERIUM» (Russia). Nonacog alfa is safe with regard to transmitted infections because proteins of animal and human origin (including albumin) are not used in the process of rFIX production. Ðharmacokinetic parameters, safety and efficacy of Innonafactor has been studied in the phase I study in patients with severe and moderate hemophilia B. The primary aims of the study were to: 1. Determine the pharmacokinetic parameters of nonacog alfa in patients with severe and moderate hemophilia B. 2. Assess the safety and tolerability of different doses of nonacog alfa in patients with severe and moderate hemophilia B. The secondary aims of this study were to: 1. Set the maximum tolerated dose of nonacog alfa in practically possible range of doses. 2. Evaluate rFIX activity and the activated partial thromboplastin time (APTT) after nonacog alfa infusions in doses 50 IU kg-1 and 75 IU kg-1. During phase I clinical study the pharmacokinetic properties, safety and tolerability of the new nonacog alpha were evaluated. After screening and washout period lasting at least 4 days 12 men, aged from 23 to 50 years old with severe (n = 6) and moderate (n = 6) hemophilia B were included in the study. Patients consecutively were enrolled in 3 groups: in the 1st group (n = 3) nonacog alfa was injected slowly intravenously in a single dose of 25 IU kg-1, in the 2nd group (n = 6) - a single dose of 50 IU kg-1, then after 4 days of observation and laboratory monitoring - a second single dose of 75 IU kg-1 was administered, in the 3rd group (n = 3) - a single dose of 100 IU kg-1 (fig.1). The introduction of the nonacog alfa in doses of 50 and 75 IU kg-1 resulted in the normalization of FIX activity and activated partial thromboplastin time (APTT) within 15 min after injection. Normal FIX activity was maintained for at least 1 h after injection of the nonacog alfa at dose of 50 IU kg-1 and for 6 h after drug administration at a dose of 75 IU kg-1. Reduction of the FIX activity less than 5% was observed not earlier than 72 h after injection of the both drug doses. Significant increase of the APTT was observed only after 12 h after injection of the nonacog alfa at a dose of 50 IU kg-1 and after 24 h after administration of the nonacog alfa at a dose of 75 IU kg-1. The pharmacokinetics of nonacog alfa was studied at doses of 50 and 75 IU kg-1 (fig.1). A single dose injection of nonacog alfa led to a rapid accumulation of drug in the blood [median value of time to reach the maximum concentration (Cmax) - Tmax amounted to 0.33 ± 0,13 h] with the achievement of the average Cmax depending on the input dose (53,18 ± 9,79 IU DL-1 for doses of 50 IU kg-1 and 94,35 ± 18,47 IU DL-1 for doses of 75 IU kg-1) and the gradual elimination of the drug from the body [median value of area under the curve based on the concentration of FIX in plasma from the time of the study (AUC0-96 h) - 1069,9 ± 321,1 IU DL-1 × h for doses of 50 IU kg-1 and 1604,2 ± 389,41 IU DL-1 × h for the dose of 75 IU kg-1, the AUC0-∞ - 1125,49 ± to 300.36 and 1700,82 ± 369,95 IU DL-1 × h, the elimination half-life (T1/2) - is 24.05 ± 7,67 and 25,18 ± 6,16 h, respectively]. Nonacog alfa was well tolerated regardless of the administered dose. The maximum tolerated dose was not established because it exceeds the studied doses of the drug. A single application of the nonacog alfa in doses from 25 to 100 IU kg-1 was not accompanied by toxic, thrombogenic, immunogenic and allergic reactions. Figure 2. Average pharmacokinetic curve of the coagulation factor IX activity in the blood plasma during administration of two doses of the drug Figure 2. Average pharmacokinetic curve of the coagulation factor IX activity in the blood plasma during administration of two doses of the drug Disclosures No relevant conflicts of interest to declare.

scholarly journals HAEMOPHILIA

2013 ◽  
Vol 4 (3) ◽  
Author(s):  
Diana S Purwanto
Keyword(s):  
Factor Viii ◽  
Prothrombin Time ◽  
Partial Thromboplastin Time ◽  
Activated Partial Thromboplastin Time ◽  
Factor Ix ◽  
Haemophilia A ◽  
Clotting Time ◽  
Serial Test ◽  
Faktor Viii ◽  
Hemofilia A

Abstrak: Hemofilia adalah kelainan perdarahan kongenital yang disebabkan oleh kekurangan faktor VIII (faktor antihemofilik) yang terkait dengan Hemofilia A, atau faktor IX (faktor Christmas) yang terkait dengan Hemofilia B. Kedua hemophilia diturunkan secara X-linked resesif, dan umumnya ditemukan pada laki-laki. Kami melaporkan kasus seorang anak berusia 4 tahun dengan riwayat memar, pendarahan berlebihan, disertai pembengkakan sendi yang nyeri dan hematoma otot, yang dicurigai mengidap hemofilia. Serial tes koagulasi dilakukan dengan hasil: jumlah trombosit, waktu perdarahan, prothrombin time (PT), thrombin clotting time (TCT), dan fibrinogen normal, sedangkan activated partial thromboplastin time (APTT) memanjang. Mixing studies dikoreksi ketika plasma normal dan adsorbed plasma ditambahkan ke plasma pasien, yang menunjukkan defisiensi faktor VIII merupakan penyebab hemofilia ini. Aktivitas faktor VIII 8% menegaskan suatu hemofilia A derajat ringan. Kata kunci: hemofilia, PT, APTT, mixing studies, faktor VIII.   Abstract: Haemophilia is a congenital bleeding disorder caused by a deficiency of factor VIII (antihaemophilic factor), which is related to haemophilia A, or factor IX (Christmast factor), associated with haemophilia B. Both X-linked are recessive, and males are affected mostly. In this case, a four year old boy, who had a history of excessive bruising and bleeding, also suffered from painful swelling of joints and muscle hematoma. He was diagnosed of suspected  haemophilia. A serial test of coagulation studies was performed. The results of platelet count, skin bleeding time, prothrombin time, thrombin clotting time, and fibrinogen were normal; whereas, the activated partial thromboplastin time was prolonged. The mixing studies were corrected when normal plasma and adsorbed plasma were added to the patient plasma, suggesting that the factor VIII deficiency was the cause of this haemophilia. The factor VIII activity was 8% which confirmed the evidence of mild haemophilia A. Keywords: haemophilia, PT, APTT, mixing studies, factor VIII.

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