V Activated Platelet. vwf. IXa VIII. Inhibition path. VIIa PAI-1 TFPI. Quick Guide To Haemostasis

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1 IIa PC AT II APC P V PS APC Va Xa AT Activated Platelet X vwf AT IXa VIIIa APC PS VIII IX Inhibition path Xa TFPI VIIa TF AT PAI-1 APC PS Xa Quick Guide To Haemostasis R

2 Screening assays in Haemostasis Anticoagulant therapy monitoring (1): Vitamin K antagonists Anticoagulant therapy monitoring (2): Heparin Assays for other anticoagulant therapy (3) isseminated Intravascular Coagulation (IC) Thrombophilia -imer assay for the exclusion of venous thromboembolism (VT) Lupus anticoagulants / Antiphospholipid antibodies For more information, visit our website at

3 Screening assays in Haemostasis 1) Questionnaire l Personal and familial history l Treatments l iseases l Clinical symptoms 2) Physical examination 3) Pre-operative Haemostasis screening assays l Prothrombin time (PT) n Screening test for the extrinsic and common pathways of coagulation (factors II, V, VII, X). Limited sensitivity to fibrinogen. n Usual normal ranges: sec (may vary between reagents, please refer to manufacturer s insert) l Activated Partial Thromboplastin Time (aptt) n Screening test for the intrinsic and common coagulation pathways of coagulation (factors VIII, IX, XI, XII, V and II). Limited sensitivity to fibrinogen. n May be normal in some forms of von Willebrand disease n Usual normal range: ratio patient/reference 1.2 l Thrombin time n xploration of fibrin formation n Usual normal range: < 21 seconds (may vary between reagents, please refer to manufacturer s insert) ffects of coagulation factors and protein levels on clotting assays FACTORS NORMAL VALUS MINIMUM LVL FOR LOW BLING RISK INFLUNC OF COAGULATION TSTS 2 PT 3 aptt 4 TT 5 XII % - N N XI % 20-30% N N VIII % 30-40% N N IX % 30-40% N N VII % 10-20% N N X % 30-40% N V % 30-40% N II % 30-40% N Fibrinogen 2-4 g/l g/l N or N or VWF % 40% N N or N Antithrombin % - N N N Protein C % - N N N Protein S % 6 - N N N 1. Approximate level in the case of a single factor deficiency. These levels may vary according to different clinical settings, e.g. haemophiliacs undergoing surgery will require higher levels of FVIII 2. Results vary as a function of sensitivity of reagents and single or multiple factor levels 3. PT: Prothrombin Time 4. aptt: activated Partial Thromboplastin Time 5. TT: Thrombin time 6. Sex and age-dependent

4 Screening assays in Haemostasis l Fibrinogen level n Quantitative assay of fibrinogen level n Usual normal range: 2-4 g/l ( mg/dl) n levated fibrinogen levels are observed in inflammatory syndrome (acute or chronic) l Platelet count n Number of circulating platelets n Usual normal range: G/L 4) Screening assays for isseminated Intravascular Coagulation (IC) PT, aptt and fibrinogen levels, as well as -imers, are generally abnormal in acute IC but may be normal during chronic and subacute IC. These screening tests are thus of limited specificity and sensitivity for the diagnosis of IC (see section on IC). Recent studies suggest that fibrin monomer may constitute early and more specific markers of IC. 5) Screening assays for thrombophilia l There are as yet no global tests available to explore all thrombophilia factors. l First-line activity assays are required for monitoring of inhibitors (see Thrombophilia section). 6) Screening tests for Lupus Anticoagulants (LA) l The screening assays are phospholipid-dependent function tests. At least two different tests are required for detection of LA (see Lupus Anticoagulants section). Bibliography: l Simple coagulation tests survival prediction in patients with septic shock. Lissalde Lavigne G et al. J Thromb Haemost 2008, 6: l Guidelines for the diagnosis and management of IC. Levi M. et al. Br J Haematol, 2009, 145, 1:24-33 l IC diagnosed based on the Japanese association for acute medicine criteria is a dependant continuum to overt IC in patient with sepsis. Gando S. et al. Thromb Res, 2009, 123, 5: l Conduites pratiques en hémostase, Charles Marc Samama, LFB monograph, 1996 l Hémostase & thrombose, La Simare éditions impression, 1994 l Hemostasis, a case oriented approach,. A. Triplett, Igaku-Shoin Medical publishers, 1985 l Recommandations pour une juste prescription des examens d hémostase en pratique médicale courante, M. Gouault-Heilmann, STV, 2006; vol.18, No1, pages l Laboratory Techniques in Thrombosis - A Manual, Second revised edition of the CAT Assay Procedures, Jespersen J, Bertina RM, Haverkate F, 1999, pages 1-308

5 Anticoagulant therapy monitoring (1) Oral anticoagulant therapy with vitamin K antagonists (VKA*) l Vitamin K antagonists reduce synthesis of both vitamin K-dependent coagulation factors (factors II, VII, IX, X) and some proteins (Protein C and Protein S). The deficiency in factors II, VII, IX and X induced by the absorption of vitamin K antagonists results in prolongation of PT and of aptt. l The Prothrombin Time is the reference test of choice for monitoring of vitamin K antagonist therapy. It is expressed as a coagulation time, using the ratio between the patient and a control, or as % prothrombin time, leading to wide inter-laboratory result variability due to the use of different analysers/reagents combination. In order to standardise the results obtained for patients on vitamin K antagonists, results are expressed as INR. l PT results expressed as INR (International Normalized Ratio) n The INR is the ratio of PT to the power ISI (International Sensitivity Index). It represents the ratio of PT that would have been obtained if an international thromboplastin reference material had been used for the test. n The ISI is a value calculated for each batch of thromboplastin reagent and varies according to the type of analyser used. ISI values are specific for pairs of reagents and instruments. The international recommendations suggest the use of a reagent with an ISI value of less than 1.7. n The control time is the geometric mean of PT values measured on at least 20 fresh plasma samples from healthy subjects (with no pathology or treatment that might interfere with coagulation). ISI Patient Time (sec) INR = ( ) Control Time (sec) l Anticoagulant therapy monitoring n Heparin followed by vitamin K antagonists l Monitoring of treatment with vitamin K antagonists with the INR (using a reagent insensitive to heparin at therapeutic doses) l Monitoring of heparin treatment - aptt (indicates the combined effect of vitamin K antagonists and unfractionated heparin) - Specific anti-xa assay (specific monitoring of anti-xa activity) l Treatment with heparin and vitamin K antagonists may be given concomitantly for 4 to 5 days until the desired therapeutic range is achieved in terms of INR (i.e. two consecutive INR of two consecutive days unchanged and in the therapeutic range). n Stable patients on vitamin K antagonists treatment The INR value should be checked weekly then monthly, and more frequently in the event of a dose change, unbalanced assay results or suspected interference by other factors. *Antivitamins K or vitamin K antagonists

6 Anticoagulant therapy monitoring (1) l N.B.: n Wide inter-patient variability n Interferences due to: l Other treatments (many drugs can interfere with vitamin K antagonists) l Other diseases l Food and drinks rich in vitamin K l Recommended therapeutic ranges (expressed in INR) INICATION INR ACCP 1, BCSH 2, GHT 3 Range Target Prophylaxis of venous thrombosis. Treatment for deep venous thrombosis (VT) and pulmonary embolism (P). Cardiac valve disease. Myocardial infarction. Atrial fibrillation. Antiphospholipid syndrome associated with recurrent VT or additionnal risk factors ACCP: American College of Chest Physicians 2 BCSH: British Committee for Standards in Haematology 3 GHT: Groupe d tude sur l Hémostase et la Thrombose Bibliography: l Guidelines on oral anticoagulation (warfarin): third edition update. Baglin T.P., Keeling.M., Watson H.G. for the British Commitee for Standards in Haemotalogy. Br J Haematol, 2005; 132: l vidence-based Management of Anticoagulant Therapy. Antithrombotic Therapy and Prevention of Thrombosis, 9th d: American College of Chest Physicians vidence-based Clinical Practice Guidelines. Holbrook A., Schulman S., Witt.M., Vandvik P.O., Fish J., Kovacs M.J., Svensson P.J, Veenstra.L., Crowther M., Guyatt G.H. Chest, 2012; 141: 152S-184S

7 Anticoagulant therapy monitoring (2) Unfractionated Heparin monitoring Unfractionated heparin (UFH) is a heterogeneous mix of polysaccharide chains of variable molecular weight. One-third of the chains have a pentasaccharide pattern that has a strong binding affinity to Antithrombin. Molecular weight: 2,000 to 40,000 alton (average: 15,000). They are used for both therapeutic and prophylactic therapy l Limitation: n Short half-life, dose-dependent n Non-specific binding n Random dose-response effect n Major bleeding risk l Sample collection and treatment: n A standardised protocol should be followed for the collection and processing of the samples. n Collection: tube containing an anticoagulant - sodium citrate 0.105/0.109 M or CTA (Citrate, Theophylline, Adenosine, ipyridamole). n Centrifugation within an hour of collection. n Stability at +20 C: 2 hours in a citrate tube or 4 hours in a CTA tube l Assays: n aptt l Widely used for monitoring UFH treatment but sensitive to certain coagulation abnormalities (deficiency or specific coagulation disorders, lupus anticoagulant) and to certain drugs such as vitamin K antagonists (during heparin-vka therapy switch) or thrombolytic drugs Note: Therapeutic ranges may vary between reagents n Anti-Xa activity: standardised measurement using an international standard (see Tables 1 and 2) n Platelet count: for the detection of heparin-induced thrombocytopenia (HIT) l HIT, Type II : - Immunoallergic reaction to the drug - Up to 3% of treated patients (1) - Generally occurs after the 5 th day of treatment - Severe thrombocytopenia, followed by life-threatening thrombotic complications n Antithrombin (AT): for the exclusion of antithrombin deficiency in the case of heparin resistance. Bibliography: l (1) Treatment and Prevention of Heparin-Induced Thrombocytopenia. Antithrombotic Therapy and Prevention of Thrombosis, 9 th ed: American College of Chest Physicians vidence-based Clinical Practice Guidelines. Linkins L.A., ans A.L., Moores L.K., Bona R., avidson B.L., Schulman S., Crowther M. Chest, 2012; 141: 495S-530S

8 Anticoagulant therapy monitoring (2) Table 1 : Unfractionated heparin: curative therapeutic range Curative treatment AMINISTRATION MO SAMPLING aptt Ratio* patient/reference Anti-Xa activity continuous intravenous infusion any time after fourth hour of treatment times 0.3 to 0.7 IU/mL discontinuous subcutaneous or intravenous infusion at the midpoint between 2 injections times 0.3 to 0.7 IU/mL Tableau 2 : Unfractionated Heparin: preventive therapeutic range Preventive treatment AMINISTRATION MO SAMPLING aptt Ratio* patient/reference Anti-Xa activity subcutaneous or intravenous infusion at the midpoint between 2 injections times 0.1 to 0.2 IU/mL *The extent of aptt prolongation differs between reagent. It is recommended that every laboratory establish their own aptt therapeutic range according to their own operating procedure

9 Low Molecular Weight Heparin (LMWH) monitoring l Low Molecular Weight Heparin is obtained by enzymatic or chemical depolymerisation of unfractionated heparin. Molecular weight: to altons (mean: a) l Anticoagulant profile: n Ratio of anti-factor Xa / anti-factor IIa activity: - UFH: 1:1 - LMWH: 2 to 5:1 (and more for same LMWH preparation) l Advantages: n More predictable anticoagulant response n Better bioavailability at low doses n Non-dose-dependent clearance n Longer half-life l Tests: n The result of global coagulation tests (aptt) are not correlated with the anticoagulant activity of LMWH n The only tests currently available are those that specifically measure anti-xa activity in plasma n An international standard for LMWH is available n Anti-Xa activity for LMWH dose adjustment should be assayed at least 48 hours after the initial injection (curative treatment) n Monitoring is not necessary during prophylactic treatment (except in the event of renal impairement, weight gain, bleeding or thrombosis risk) n Monitoring is particularly recommended in children and elderly subjects n Platelet count should be measured: - within the first 24h of treatment - thereafter, twice weekly throughout treatment. Bibliography: l Parenteral anticoagulants. Antithrombotic Therapy and Prevention of Thrombosis. 9 th ed: American College of Chest Physicians vidence-based Clinical Practice Guidelines. Garcia.A., Bagin T.P. Witz J., Samama M.M. Chest, 2012; 141: e24s-e43s

10 Table 3: Heparin derivatives (LMWH and fondaparinux) available in France at curative doses in (1, 16, 18) Product Indications osage Peak anti-xa activity Mean values 1 m±sd Overdose threshold 2 APTT prolongation (if measured) LOVNOX (INN enoxaparin) FRAGMIN (INN dalteparin) FRAXIPARIN (INN nadroparin) INNOHP (INN tinzaparin) FRAXOI (INN nadroparin) ARIXTRA (INN fondaparinux) ARIXTRA (INN fondaparinux) LMWH: twice-daily injection regimen: sample taken at peak activity, 3 to 4 h after injection VT with or without P Acute coronary syndrome stablished VT Unstable angina Non-Q-wave myocardial infarction 100 IU/kg/12h (1 mg/kg/12h) 100 to 120 IU/ kg/12h 85 IU/kg/12h 1.20 ± 0.17 IU/mL 0.6 ± 0.25 IU/mL 1.0 ± 0.2 IU/mL LMWH: once-daily injection regimen: sample taken at peak activity, 4 to 6 h after injection stablished VT Non-serious P stablished VT 175 IU/kg/24h 171 IU/kg/24h 0.87 ± 0.15 IU/mL 1.34 ± 0.15 IU/mL IU = International Units VT: eep Vein Thrombosis; P: Pulmonary mbolism INN: International Nonproprietary Name 1 NB: mean values measured in subjects receiving treatment with each LMWH; 2 Threshold values above which dose reduction can be considered; 3 For patients weighing between 50 and 100 kg; 5 mg/24h for patients weighing < 50 kg; 10 mg/24h for patients weighing > 100 kg N 1.0 IU/mL N Moderate prolongation Moderate prolongation Moderate prolongation < 1.5 IU/mL Prolongation < 1.8 IU/mL Fondaparinux: once-daily injection regimen: sample taken at peak activity, 2 to 3 h after injection stablished VT 7.5 mg/24h Non-serious P µg/ml N Acute coronary syndrome 2.5 mg/24h 0.45 µg/ml N Moderate prolongation No prolongation No prolongation

11 Assays for other anticoagulant therapy (3) Replacement therapy monitoring Hirudin - desirudin (Revasc ) A protein produced by the salivary glands of leeches. irect thrombin inhibitor. Recombinant hirudins are currently commercially available. l Indications (depend on drug and country) n Treatment of patients with heparin-induced thrombocytopenia (HIT) n Prevention of thromboembolic complications after orthopaedic surgery (total hip or knee replacement) in patients with a history of HIT l Laboratory tests n Treatment l aptt: there is a direct relationship between the aptt prolongation and the plasma hirudin concentration, except at high concentrations. l carin clotting time l carin chromogenic assay (CA): for the quantitative determination of hirudin and its analogues n Prophylaxis No recommendation for monitoring, except in the case of renal or hepatic failure or combined treatment with oral anticoagulants. anaparoid Sodium (Orgaran ) Mixture of heparan sulphate (~ 84%), dermatane sulphate (~ 12%) and chondroitin sulphate (~ 4%). Molecular weight: approximately altons. Specific inhibitor of factor Xa. l Indications (according to country) n Treatment of patients presenting HIT n Prophylaxis of post-operative deep venous thrombosis following total hip or knee replacement surgery (in patients with a previous history of HIT) l Laboratory tests n Monitoring not necessary for prophylactic treatments, but recommended for curative treatment. - mild effect on time-based assays (PT and aptt) - anti-xa assays (specific protocol)

12 Assays for other anticoagulant therapy (3) New anticoagulants monitoring Fondaparinux (Arixtra ) Fondaparinux, a pentasaccharide, is a synthetic and selective inhibitor of factor Xa. The administration of this drug is simple: 1 subcutaneous injection per day at a fixed dose regardless of patient characteristics. The half-life varies according to age and is between 17 and 21h, with a peak concentration 2 to 3h after injection l Indications n Prevention of thrombosis in orthopaedic surgery n Prevention of thrombosis in high-risk abdominal surgery n Prevention of thromboembolic events in patients at risk and bedridden for an acute medical problem (cardiac failure, respiratory problems, etc) n Curative treatment of acute deep venous thrombosis n Curative treatment of acute pulmonary embolism l Therapeutic dosage n Preventive treatment: 2.5 mg (or 1.5 mg for renal failure patients) / day n Curative treatment: 7.5 mg/day for patients weighing between 50 and 100 kg l Laboratory tests Although no monitoring is officially recommended, certain clinical situations may require a dosage: n Haemorrhagic or thrombotic accidents n Additional surgery n Renal failure n etc. Anti-Xa activity assay with dedicated controls and calibrator for the monitoring of Fondaparinux (STA - Fondaparinux Control and Calibrator) n Measuring range: 0.1 to 2 µg/ml l The assay measuring range covers all doses irect factor Xa inhibitors Rivaroxaban (Xarelto ) - Apixaban (liquis ) Rivaroxaban and apixaban are synthetic direct factor Xa inhibitors. They have a short half-life and are almost immediately bioavailable upon oral administration. There is currently no antidote available. It may be necessary to measure anticoagulant activity in certain patients or in certain clinical situations.

13 l Indications n VT prophylaxis after total knee or hip replacement surgery n Atrial fibrillation n VT and P treatment (rivaroxaban) n Secondary prevention of VT (rivaroxaban) n Acute coronary events, in combination with antiplatelet drugs l Specific test: rivaroxaban anti-xa activity is assayed using specific controls and calibrators (STA -Rivaroxaban Control & Calibrator) l For specific determination of rivaroxaban anticoagulant activity: l Test to be performed 2 to 4 h after latest intake l Working range: 20 to 500 ng/ml irect Thrombin Inhibitors (TIs) TIs (abigatran -Pradaxa -, Argatroban, Bivalirudine, etc) are direct inhibitors of thrombin with varied therapeutic range. They have a short half-life and practically immediate bioavailability. TIs have no antidotes. It may be necessary to measure anticoagulant activity for certain drugs and in certain patients. l Indications (according to drug and country) n Treatment of patients with heparin-induced thrombocytopenia (Argatroban, Bivalirudine ) n Prevention of thrombosis n Prevention of stroke in atrial fibrillation n Prevention of thromboembolic complications following orthopaedic or cardiac surgery. l Laboratory tests n aptt: there is a direct relationship between the aptt prolongation and the TIs concentration in plasma, however: l This test is greatly affected by different variables (presence of lupus anticoagulants, factor deficiencies, etc) and concomitant treatments (vitamin K antagonists, heparin, etc) l The measuring range is unsuitable for TIs l There is poor linearity with high doses of TIs n carin clotting time (CT): this is considered as the reference test, but: l It is dependent on the patient s thrombin and fibrinogen levels. l There is no standardisation n carin chromogenic assay (CA): is a specific and quantitative assay of TIs levels

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15 isseminated intravascular coagulation (IC) l IC is an acquired syndrome characterised by excessive systemic intravascular activation of coagulation, with no specific site and due to a variety of different causes and origins (ISTH 2001). l iagnosis of IC is based on clinical criteria (presence of underlying disease or specific medical conditions such as septicaemia, trauma, malignant tumour, etc) and laboratory criteria. l There are 2 types of IC: n Compensated or «non-overt» IC n ecompensated or «overt» IC Non-overt IC is defined as IC with no signs of haemorrhage or thrombosis. iagnosis of compensated IC is based primarily on laboratory criteria. Overt IC consists of established, manifest and serious IC. iagnosis is based on a combination of clinical signs and different laboratory tests. Fibrinogen Thrombin Fibrin Monomer Plasmin Plasmin Fibrinogen degradation products (FP) + + FXIII Stabilised fibrin clot Plasmin -imers Fibrin degradation products (FPn) + Solubles complexes = Fibrin monomer + FP Fibrin monomer + FPn Fibrin monomer + fibrinogen

16 iagnosis of IC Clinical diagnosis Clinical signs of IC are either thrombotic signs or haemorrhagic signs, or both at the same time. Patients are classified according to 3 different physiological clinical scoring systems. Laboratory diagnosis There are no laboratory tests truly specific for IC. PT, aptt and fibrinogen are generally abnormal in acute IC, but they may be normal in chronic or subacute IC. These screening tests are thus of limited specificity and sensitivity for diagnosis of IC. Recent studies show assay of fibrin monomers to be an early marker for IC. etermination of IC defined by the ISTH is based on the presence of underlying disorders and on clotting tests, which allow the identification of patients presenting non-overt and overt IC. PRSNC OF AN UNRLYING ISORR ASSOCIAT WITH IC YS: proceed with ISTH overt IC score PT, APTT, Fibrinogen, platelet count, fibrin-related markers NO: stop Score : l Platelet count: > 100 G/L = 0 < 100 G/L = 1 < 50 G/L = 2 l Fibrinolysis: (e.g: -i, FP, FM): No increase = 0 moderate increase = 2 high increase = 3 l PT prolongation: < 3 sec. = 0 3 sec. < PT < 6 sec. = 1 > 6 sec. = 2 l Fibrinogen: > 1 g/l = 0 > 1 g/l = 1 Overall score : 5 compatible with overt-ic (repeat daily) < 5 non-suggestive of overt IC (repeat the next 1-2 days) Bibliography: l isseminated Intravascular Coagulation. Levi M, Cate H. ten. NJM, 1999, l iagnostic Criteria and Laboratory Tests for isseminated Intravascular Coagulation. Kaneko T., Wada H. J. Clin. xp. Hematopathol. 2011; 51: l iagnosis of isseminated Intravascular Coagulation and related consumptive coagulopathies. Mammen F. Caduceus Medical Publishers Inc., Patterson, NY, USA, 1992 l Laboratory diagnosis of IC and activated coagulation. Schmaier AH., IC assessment ABC monography,1989, 2-18 l Towards efinition, Clinical and Laboratory Criteria, and a Scoring System for isseminated Intravascular Coagulation (ISTH), Taylor F.B., Toh C.H., Hoots W.K., Wada H., Levi M., Thromb Haemost, 2001; 86: l iagnostic criteria and laboratory tests for disseminated intravascular coagulation. Kaneko T, Wada H. J. Clin. xp. Hematopathol 2011; 51: 67-76

17 Thrombophilia l Thrombophilia may be defined as the tendency to develop thrombosis: n Hereditary thrombophilia (congenital or juvenile), is a genetically determined tendency to develop venous thrombosis. n Acquired thrombophilia. Classification l Hereditary thrombophilia (congenital) n Associated with a family history of venous thrombosis (in most cases). n Recurrent thrombosis in certain patients. n Not always associated with a clear triggering factor. n Affects young subjects: < 60 years. l Acquired thrombophilia n No associated family history (generally). n Associated with transient triggering event such as: l Traumatic injury. l Pregnancy - in particular during the post-partum period. l Immobilisation (i.e., stasis, long flights, etc). l Post-operative period. l Advanced age (first event > 60 years). n Oestrogen therapy. n Antiphospholipid antibodies. n Can also be associated with other clinical disorders such as: l Cancer. l Heparin-induced thrombocytopenia. iagnostic tests for thrombophilia l Prelimary Screen: n Antithrombin, Protein C, Protein S, resistance to activated Protein C / Factor V Leiden, prothrombin gene mutation, lupus anticoagulants (LA) and antiphospholipid antibodies (APA). l Secondary Screen: n Fibrinogen, homocysteine. n Investigation of fibrinolysis (tpa, etc.) n Assay of factor VIII, etc.

18 Thrombophilia Prevalence in thrombotic subjects CAUSS USUAL VALUS RLATIV RISK PRVALNC Antithrombin % in heterozygous 1-2% in patients patients with VT Protein C % 6 3% in patients with VT % in the Protein S* % 5 in patients general population 2-3% in thrombotic subjects 5% in the general FV leiden 3-5 heterozygous patients population >20% in thrombotic subjects FII genous polymorphism 2-3 heterogenous patients 2% in the uropean population αβ2gp1 + ACL 2.2 *depends on age and sex l Other tests n Other Haemostasis elements. l Sample collection procedure Samples used for confirmation of thrombophilia must be collected at least 3 months after the latest thrombotic event and in accordance with the time limits associated with the test to be performed after the end of treatment. n Samples should not be taken in the following cases: l uring acute episodes of VT/P l uring oral anticoagulant treatment with vitamin K antagonists, PC and PS levels are reduced by 50% and levels of activity are reduced. l It is necessary to wait one month after discontinuation of treatment with vitamin K antagonists before performing Protein C and Protein S assays. l In the case of heparin treatment, which could reduce antithrombin levels l In pregnant women and for up to 3 months after childbirth l In patients on oestrogen therapy until 2 cycles after treatment discontinuation (e.g. contraceptive pills) l In patients treated with L-asparaginase l In patients with nephritic syndrome, hepatic impairment, IC or an inflammatory condition. l In the case of positive screening tests for LA, further screening should be repeated after 12 weeks. Low levels of PC and PS are seen in normal paediatric samples. In tests performed on paediatric samples, normal values for patients of the same age group should be established before the diagnosis is established. Bibliography : l Inherited thrombophilia: part 1. Lane et al. Thromb Haemost. 1996; 76: 651. l High prevalence of antithrombin III, protein C and S deficiency, but not factor V Leiden mutation in venous thrombophilic Chinese patients in Taiwan. Shen MC, Lin JS, Tsay W, Thromb Res. 1997; 87: l Risk factors for venous thrombotic disease. Rosendaal FR. Thromb Haemost. 199; 82: l Protein C and protein S deficiencies are the most important risk factors associated with thrombosis in Chinese venous thrombophilic patients in Taiwan. Thromb Res. 2000; 99: l Management of thrombophilia, Bauer K. A., J Thromb Haemost. 2003; 1: l Screening for thrombophilia: a laboratory perspective, Jennings I., Cooper P., Br J Biomed Sc. 2003; 60: 39-51

19 -imer assay for exclusion of Venous Thrombombolism (VT) l It has been shown that only -imer is of diagnosis value in ruling out deep venous thrombosis or pulmonary embolism. -imer fragments are formed through the degradation of polymerised fibrin by plasmin. N.B.: High levels of -imers do not necessarily imply VT/P since they may be associated with many other causes. levated -imers may also be found in samples: n from pregnant patients n from older subjects n from patients with infection n following traumatic injury n during the post-operative period n from patients with cancer n from hospitalised patients (who generally have a higher baseline -imer level than ambulatory patients) n from patients with inflammatory syndrome l Value of -imers in the diagnosis of deep venous thrombosis: n Negative Predictive Value (NPV) close to 100% n Use of -imers combined with clinical pretest prohability score clinical pretest prohability score (Wells score) l With a score < 2 for patients with suspected VT l With a score 4 for patients with suspected P l May be used for all patients with suspected VT n Non-invasive method n Limits the number of tests required as well as the need for imaging n Improves diagnosis

20 -imer assay for exclusion of Venous Thrombombolism (VT) l Several studies performed with STA -Liatest -i have shown a negative predictive value (NPV) pretty to close to 100% in ambulatory patients using a threshold value for -imers of 500 ng/ml (i.e. 0.5 µg/ml). Clinical validation of STA -Liatest -i in ruling out diagnosis of VT and P. Number of patients Pathologies NPV STA -Liatest -i 386 P 100% 501 P 99.4% 222 P 100% 114 TVP/P 100% Bibliography: l valuation of a new, rapid, and quantitative imer test in patients with suspected pulmonary embolism. Oger. and al., Am. J. Respir. Crit. Care Med. 1998; 158: l Performances of a new, rapid and automated microlatex imer assay for the exclusion of pulmonary embolism in symptomatic outpatients. Reber G. et al., Thromb Haemost. 1998; 80: l imer testing in patients with suspected pulmonary embolism. Comparison of 2 rapid quantitative assays STA Liatest i and vidas ddimer with an LISA. Lecourvoisier C. et al., ASH l Comparative study of 4 new and rapid imer assays to exclude deep venous thrombosis or pulmonary embolism. Breton. et al., Thromb Haemost. 1997; suppl 1 844: 720.

21 Lupus Anticoagulants (LA) / Antiphospholipid antibodies (APA) l Antiphospholipid antibodies are a heterogeneous family of antibodies directed against proteins bound to negatively charged phospholipids. Lupus-type inhibitors belong to this family of antibodies as do anticardiolipin antibodies. The presence of antiphospholipid antibodies is a biological marker for antiphospholipid syndrome (APS). l APS is an autoimmune disease associated with high risk for thrombosis, recurrent spontaneous miscarriage, thrombocytopenia and numerous other clinical manifestations. l Lupus inhibitor is also known as «antiprothrombinase anticoagulant antibody» or «lupus anticoagulant» (LA). n LA is an acquired abnormality affecting between 1 and 5% of the general population. However, only 15 to 20% of these individuals are positive for control testing performed several months afterwards. n In vitro, LA results in prolonged coagulation times in phospholipiddependent tests (e.g. aptt or PT as well as certain APCR tests). iluted Russell s viper venom time (drvvt) is a specific test used for LA screening. n In vivo, LA is associated with a risk of thrombosis that may result in obstetric, neurological stroke, renal or pulmonary complications. l A single test is not sufficient to allow the diagnosis of this syndrome. l In some patients, transient antiphospholipid antibodies may be detected due to infection or to another treatment, despite the absence of any clinical signs. iagnostic decision tree for screening for LA (1) according to ISTH recommendations Screening test Mixing studies Confirmatory test STA -Staclot RVV Screen (drvvt) prolonged time* STA -Staclot RVV Confirm (drvvt) AN PTT-LA (APTT) prolonged time Ratio patient time > 1.2 referent time Patient plasma + Pool Norm no OR Staclot LA (APTT) CT correction CT > 8 sec NR > 1.2 LA Negative Factor assays LA Positive NR: Normalized Ratio; CT: Clotting Time * If OAT patient, mix 1:1 plasma patient - Pool Norm ** according to Rosner Index or ICA calculation (1)

22 Lupus Anticoagulant (LA) / Antiphospholipid antibodies (APA) Laboratory diagnosis iagnosis may only be made on the basis of two types of test: immunological tests with screening for APA and/or coagulation tests specific for LA. The recommendations of the «Scientific Subcommittees of the International Society on Thrombosis and Haemostasis» (ISTH) are as follows: 1) Lupus Anticoagulants (LA) Must be detected in plasma on at least two occasions separated by a minimum interval of 12 weeks: l Screening step: detection of increased coagulation time during a phospholipiddependent test; n At least 2 screening tests must be performed before LA can be ruled out: l The first-line test is the RVV test. l The second-line test consists of sensitised aptt containing silica activator and a low concentration of phospholipids. l Identification step for the presence of a coagulation inhibitor: 50/50 mix of patient + control (a commercially available pool may be used). l Confirmation step indicating that the inhibition is phospholipid-dependent; the selected test contains a high phospholipid concentration. It must be based on the same principle as the screening test. xclusion of associated clotting disorder. 2) Anticardiolipin antibody (acl) (IgG and/or IgM) May be present in serum or plasma, in moderate to high concentrations (e.g. > 40 GPL or MPL, or > 99th percentile), on at least two occasions, separated by a minimum interval of 12 weeks, determined using a standardised LISA method. 3) Anti-ß2 glycoprotein I antibodies (IgG and/or IgM) May be present in serum or plasma (titre > 99th percentile), on one or two occasions, separated by a minimum interval of 12 weeks, determined using a standardised LISA method, in accordance with the recommended operating procedure. Bibliography: l Pengo A, Update of the guidelines for lupus anticoagulant detection. J. Thromb Haemost. 2009; 7: l Miyakis S et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost. 2006; 4:

23 AT H A M O S T A S I S PAI-1 tpa FP -imer Plasminogen Plasmin Fibrin Fibrinogen IIa TM IIa PC II APC PS V PS APC Va Xa AT Activated Platelet X vwf AT XI IXa VIIIa APC PS VIII AT XIa IX Activation pathways Coagulation Fibrinolysis Xa TFPI VIIa TF AT Inhibition pathways PAI-1 APC PS Xa AT TFPI

24 agencel2r.com iagnostica Stago - All rights reserved - Non-contractual illustration - 07/ Ref For further information, please contact: At the Heart of Haemostasis iagnostica Stago S.A.S. RCS Nanterre B , allée Thérésa Asnières sur Seine France Ph.: +33 (0) Fax: +33 (0) webmaster@stago.com