Blood Coagulation Tests Department of Laboratory Medicine WooIn

Blood Coagulation Tests Department of Laboratory Medicine Woo-In Lee

Homeostasis (항상성) Procoagulant Regulatory Coagulation proteins Endothelium Platelets

Normal Endothelial Cell : Damaged Vessel : Anti-thrombotic state -항혈소판, -항응고, -섬유소용해 Thrombotic state -Platelet activation -Adhesion -Prothrombotic

Primary Hemostasis • Platelet plug : key : – 혈관수축 – 혈소판 adhesion aggregation – 작은 혈관손상의 지혈 • Function of platelet – – 1. Adhesion 2. Release 3. Aggregation 4. Coagulant activity

Secondary Hemostasis • Fibrin clot : key –응고인자 활성화 –큰 혈관손상 –견고한 haemostatic plug

Three factors for Hemostasis • Vascular factors – local vasoconstriction (immediate reaction) – compression of injured vessels by blood extravasated into surrounding tissues • Platelet factors – adhere to the site & form aggregates (hemostatic plugs) – release factors to augment vasoconstriction – vessel wall repair (platelet-derived growth factor) • Plasma factors

Coagulation Cascade Intrinsic pathway Tissue factor Extrinsic pathway a. PTT Common pathway PT

Regulatory mechanisms • Normally prevent activated coagulation reactions – local thrombosis or DIC • • Antithrombin III, protein C, protein S, etc Fibrinolytic system Plasmin-plasminogen system etc

Extrinsic pathway Intrinsic pathway TF FVIIa FXa Thrombin Fibrinolytic System XL-Fibrin

Coagulation Tests ** Tests for Hemostatic plug 1. Bleeding time Vessel contraction & primary hemostasis 2. Platelet count 3. Platelet function test 1) Adhesion test … v. WD, Bernard Soulier, uremia

2) Aggregation test … ADP, collagen, thrombin, epinephrine, ristocetin 응집률, 속도

** Tests for fibrin plug 1) Prothrombin time – 환자혈장 + tissue thromboplastin + 칼슘 Factor VII activation Fibrin clot 시간 측정 – Report 단위: sec, %, INR 2) a. PTT – Factor XII, XI 응고인자에 대한 활성제(kaolin, ellagic acid, celite), 혈소판 대용 물질인 인지질 첨가 3) Thrombin time – hypofibrinogenemia, 억제인자(헤파린, FDP) 4) Fibrinogen

5) Coagulation factor assay – VIII, IX, XII, prekallikrein, HMWK…a. PTT – VII … PT – V, X …PT or a. PTT 6) von Willebrand factor - subendothelial cell, megakaryocyte에서 생성되어 platelet adhesion - factor VIII 과 복합체를 이루며 순환 - Ristocetin cofactor assay … v. WF의 기능 검사 - ristocetin에 의한 혈소판 응집정도는 혈장의 v. WF의 활성도와 비례 - v. WF 항원(v. WF: Ag)

** Fibrinolysis test * Fibrinolysis … fibrin clot 이 다시 용해되는 과정 * Plasmin … fibrin, fibrinogen 모두 분해

FDP test – fibrin, fibrinogen degradation product DIC screening, hyperfibrinolysis, thromboembolic disease 증가 D-dimer - fibrin clot이 있었음을 의미, 음성인 경우 thrombosis 진단을 배제

Acquired inhibitor • 혈우병, 자가면역성 질환(Lupus anticoagulant) • Mixing test • Normal plasma와 mix 하여 검사 • Correct : factor deficiency • VIII 응고인자 항체 • VIII 응고인자 일정량을 불활성화 시키는 inhibitor activity • Pt plasma + Normal plasma residual activity of factor VIII 측정 • 1 Bethesda unit: 1 m. L내의 응고억제인자가 응고인자 VIII 활성도를 50% 로 감소시키는 양

• Lupus anticoagulant – 항인지질 항체(antiphospholipid antibody, APA)의 일종 – 자가면역성, 동종면역성 면역글로블린 – a. PTT 검사시 인지질에 작용…a. PTT 지연 – 출혈성 경향은 없고 혈전증, 뇌졸증, 습관성 유산, 폐전색증 보임 • Antiphospholipid Antibody – SLE, autoimmune disease, lymphoprolierative disease – Anticardiolipin antibody

Natural Anticoagulants • Anti-thrombin – Factor Xa, thrombin 억제 – Heparin에 의해 활성도 증가 – 유전, 간질환, DIC, oral contraceptive, preeclampsia • Protein C – Thrombin에 의해 활성화, factor Va, VIIIa을 억제 • Protein S – Protein C의 coenzyme • -2 macroglobulin, heparin cofactor II – Thrombin 억제

항응고제 추적 검사 • Oral anticoagulant 추적검사 – PT의 INR로 보고한다 – Therapeutic range INR 2 ~ 4 – INR(International Normalized Ratio) = ( pt PT/normal PT) ISI *ISI(International thromboplastin) Sensitivity Index of the

• 헤파린 추적검사 – a. PTT 1. 5 ~ 3배이다 – ACT(Activated clotting time) – LMWH때는 a. PTT, ACT모두 유용하지 않음 • 혈전용해 치료(Thrombolytic therapy) 추적 검사 – urokinase, streotpkinase, etc – TT(1. 5 ~ 5 배), fibrinogen

혈전성 질환 검사 • 응고항진(Hypercoagulable state), 후천적 요인, 가족 력 동반, 유전적 요인 …복합적 결과 • Laboratory Tests – APC resistance, protein C, S – Anti-thrombin – Anti-phospholipid Antibody – Lupus anticoagulant – Plasminogen – Dysfibrinogenemia – Heparin cofactor II

Extrinsic pathway Intrinsic pathway TF FVIIa FXa Thrombin Fibrinolytic System XL-Fibrin