M1 LAB EVAL HEMOSTASIS

• ANTICOAGULANTS NOT TO BE USED

  EDTA

  Heparin

  Oxalates
• EDTA


  - Don't preserve labile clotting factors

  - Inhibits thrombin-fibrinogen reaction

  - Only for platelet count; not for coagulation studies
• Heparin

  
  

  -Binds with anti-thrombin III

  - Inhibits all reactions in coagulation

  - For platelet retention test/glass bead retention test only

  • Affects cyclooxygenase

  • Inhibits most clotting factors
• Oxalates


  •Shortened clotting time because it forms insoluble complexes/precipitates

  • Affects photo-optical clot detection
• Evacuated Tube System


  • Preferred over syringe method

  • Blood directly mixes with anticoagulant
• ORDER OF DRAW


  • Light blue

  • Red top tube

  • EDTA
• 1st syringe


  sample collected is discarded or can be used for other serological tests
• 2nd syringe


  collected for coagulation studies
• Short draw


  Whole-blood volumeless than 90%of required volume or less than manufacturer specified minimum.PT and PTT are falsely prolonged.
• Specimen clot


  Each specimen isinspected visuallybefore centrifugation or during analysis; even a small clot interferes with hemostasis test results
• Visible hemolysis


  Pink or red plasma indicates in vitro activation of platelets and coagulation; unpredictable hemostasis test interference. Further, hemolysis interferes with optical endpoint coagulometer results.
• Lipemia or icterus


  Optical instruments may fail to measure clots in cloudy or highly colored specimens. Interferes with chromogenic substrate methods. The practitioner must employ an electro-mechanical detection method instrument.
• Tourniquet application >1 minute

  Blood stasis activates endothelial cells and elevates the concentration of von Willebrand factor and fibrinogen, falsely shortening clot-based test results.
• Specimen storage at 1-6° C

  Storage at refrigerator temperatures causes precipitation of large von Willebrand factor multimers, activation of coagulation factor VII, activation of platelets, and destruction of platelet integrity.
• Specimen storage at >25° C


  Storage at above standard room temperature causes coagulation factors V and VIII to deteriorate.
• Platelet Poor Plasma (PPP)

  •Platelet count:<10x109 platelets/L•Centrifugation:10-15 min, 2000-2500rpm•Test within2 hours•Refrigerated temp:<4 hours•Freezing temp:-20 to 070 ̊C•Used for coagulation studies
• Platelet Rich Plasma (PRP)

  •Platelet count:250x109 platelets/L•Centrifugation:10-15 min, 60-100rpm• Used for"platelet studies"• Stored at room temperature
• Drugs to be avoided

  • Aspirin

  • Heparin

  • Warfarin/Coumadin

  • Penicillin
• Aspirin


  • Inhibits cyclooxygenase

  • Platelet aggregation test: no intake within 7 days

  • Bleeding time: no intake within 24 hours
• Warfarin/Coumadin


  • Antagonist of prothrombin group and vitamin K dependent clotting factors

  • Prevents gamma carboxylation of vitamin K on clotting factors
• Penicillin


  •Alters blood vessels• Induces hemolysis• Carbenicillin
• Carbenicillin


  most potent penicillin capable of affecting platelet function
• FACTORS THAT AFFECTS THE SPECIMEN

  • Tissue thromboplastin contamination

  • Glass surfaces

  • Temperature

  • Hemolysis

  • Tourniquet application

  • Increased pH

  • Polycythemia vera

  • Amount of anticoagulant
• Tissue thromboplastin contamination


  - Prematurely activates clotting process (extrinsic pathway)

  - Must only be activated when reagent is added
• Glass surfaces


  Associated with collagen for in vitro activation of clotting process (intrinsic pathway)
• Temperature


  •FV and FVIII:deteriorates if left at room temp for extended period of time•FVII and FXI:prematurely activates at ref temp (4C)
• Hemolysis


  -Releases tissue thromboplastinlike substance that will activate clotting system-Release ADPthat causes platelet aggregation
• Tourniquet application


  - Prolonged tourniquet application causes venous stasis

  - Activates clotting factors
• Increased pH


  - Associated with loss of carbon dioxide that deteriorates clotting factors

  - Sample must be unopened and tested within 6 hours
• Polycythemia vera


  - Increases hematocrit by >50%

  - Prolongs clotting time test
• Amount of anticoagulant


  - Blood to AC ratio: 9:1 using 3.2% sodium citrate - Citrate: anticoagulant of choice for coagulation studies

  - Incomplete filling of tubes can result to increased amount of citrate (prolonged)
• ANTICOAGULANTS NOT TO BE USED

  EDTA

  Heparin

  Oxalates
• EDTA


  - Don't preserve labile clotting factors

  - Inhibits thrombin-fibrinogen reaction

  - Only for platelet count; not for coagulation studies
• Heparin


  -Binds with anti-thrombin III- Inhibits all reactions in coagulation- Forplatelet retention test/glass bead retention test only

  • Affectscyclooxygenase• Inhibits most clotting factors
• Oxalates


  •Shortened clotting timebecause it forms insoluble complexes/precipitates

  • Affectsphoto-optical clotdetection
• Evacuated Tube System


  • Preferred over syringe method

  • Blood directly mixes with anticoagulant
• ORDER OF DRAW


  • Light blue

  • Red top tube

  • EDTA
• 1st syringe


  sample collected is discarded or can be used for other serological tests
• 2nd syringe


  collected for coagulation studies
• Short draw


  Whole-blood volumeless than 90%of required volume or less than manufacturer specified minimum.PT and PTT are falsely prolonged.