1.
Blood studies: Hematology & Coagulation Mrs. Nur Aisyah Aziz Pathology Practical 27.12.2010

2.
Test of Hemostasis & Coagulation <ul><li>Bleeding disorder </li></ul><ul><li>Vascular injury </li></ul><ul><li>Trauma </li></ul><ul><li>Coagulopathies </li></ul>

3.
Laboratory Investigation of Hemostasis <ul><li>5 primary screening test to diagnosed suspected coagulation disorders: </li></ul><ul><li>Platelet count, size and shape </li></ul><ul><li>Bleeding time – platelet fx. & capillaries wall </li></ul><ul><li>PTT – ability to clot </li></ul><ul><li>PT – fx. of second-stage clotting factors (????) </li></ul><ul><li>Fibrinogen level </li></ul>

4.
Laboratory Investigation of Hemostasis <ul><li>Factor assay – definitive coagulation studies of specific clotting factors </li></ul><ul><li>Fibrinolysis – to address problem with fibrinolytic system </li></ul><ul><li>Euglobulin clot lysis </li></ul><ul><li>Factor XIII </li></ul><ul><li>Fibrin split product </li></ul><ul><li>The investigations of hypercoagulable status </li></ul><ul><li>PT </li></ul><ul><li>PTT </li></ul><ul><li>Fibrinogen test </li></ul><ul><li>Antiplatelet factors </li></ul><ul><li>Anticoagulant factors </li></ul><ul><li>Fibrinolysis tests </li></ul>

5.
1. BLEEDING TIME <ul><li>Primary phase of hemostasis </li></ul><ul><li>Best single screening test for platelet screening tests platelet fx disorder & coagulation disorder </li></ul><ul><li>This test is of value in detecting vascular abnormalities and platelet abN & def. </li></ul><ul><li>Not recommended for routine presurgical workup </li></ul><ul><li>Procedure: Ivy Method </li></ul>

6.
Thrombin time (TT) <ul><li>Stage III fibrinogen defects can be detected by TT test </li></ul><ul><li>Detection: DIC, hypofibrinogenemia </li></ul><ul><li>Useful for monitoring streptokinase therapy </li></ul><ul><li>Test mechanism: time for plasma to clot when thrombin is added </li></ul><ul><li>N = clot forms rapidly </li></ul><ul><li>abN = no clot  presence of stage III def. </li></ul>

7.
Partial Thromboplastin Time (PTT); Activated Partial Thrombin Time (APTT) <ul><li>PTT – screens for coagulation disorder </li></ul><ul><li>Specific detection – Intrinsic thromboplastin system & defect in extrinsic coagulation mechanism pathway </li></ul><ul><li>APTT – detect def. in intrinsic coagulation system, incubating anticoagulants, monitor heparin therapy </li></ul>

8.
Activated Coagulation Time (ACT) <ul><li>To evaluate coagulation status </li></ul><ul><li>ACT responds linearly to heparin level changes </li></ul><ul><li>Responds to wider range of [heparin] than does the APTT </li></ul><ul><li>Bedside procedure – requires only 0.4mL of blood </li></ul><ul><li>Routinely use during dialysis, coronary artery bypass procedures, arteriograms & percutaneous transluminal coronary arteriography </li></ul><ul><li>HARD TO STANDARDIZE, NO CONTROLS AVAILABLE = results back-up with APTT </li></ul>

9.
Prothrombin Time (Pro Time; PT) <ul><li>Prothrombin – a protein, produced by liver, blood clotting </li></ul><ul><li>Production – depends on adequate vit. K intake & absorption </li></ul><ul><li>Clotting process – Prothrombin  THROMBIN </li></ul><ul><li>ProT reduced in liver ds. </li></ul><ul><li>Important screening test for coagulation dx. </li></ul><ul><li>Measures – potential defect in Stage II clotting mechanism (extrinsic system) </li></ul><ul><li>Used to evaluate disfibrinogenemia, heparin & coumarin effect, liver failure & vit. K def. </li></ul>

10.
Others: <ul><li>Coagulant factors (Factor assay) </li></ul><ul><li>Plasminogen (Plasmin; Fibrinolysin) </li></ul><ul><li>Fibrinolysis (Euglobulin lysis yime; Diluted whole blood clot lysis) </li></ul><ul><li>Fibrin Split Products (FSPs); Fibrin Degradation Products (FDPs) </li></ul><ul><li>D -Dimer </li></ul><ul><li>Fibrinopeptide A (FPA) </li></ul><ul><li>Prothrombin Fragment (F1+2) </li></ul><ul><li>Fibrin monomers (Protamine Sulfate Test; Fibrin Split Products) </li></ul><ul><li>Fibrinogen </li></ul><ul><li>Protein C (PC antigen) </li></ul><ul><li>Protein S </li></ul><ul><li>Antithrombin III (AT-III; Heparin cofactor activity) </li></ul>

11.
Platelet count; Mean platelet volume (MPV) Platelet – Fx: blood clotting, vascular integrity & vasoconstriction, adhesion & aggregation activity Production: BM Life span: 7.5 days 2/3 in circulating blood + 1/3 in spleen MPV – uniformity of platelet size, diff. dx of thrombocytopenia ??? Clinical Implications of platelet count & MPV: abN  &  ??? Interfering factors

12.
Lab report <ul><li>??? test </li></ul><ul><li>Test </li></ul><ul><li>Reference range </li></ul><ul><li>Clinical implications </li></ul><ul><li>Interfering factor(s) </li></ul><ul><li>??? Clinical implication & Interfering factors </li></ul><ul><li>prolonged vs. shortened TT, APTT & </li></ul><ul><li>increased PT vs. normal PT </li></ul>