Lab Eval of Hemostasis Flashcards
Platelet Count High
Acute phase reaction Early CML Essential thrombocytosis Polycythemia vera Post splenectomy
Platelet Count Low
DIC Hemolytic anemia Hypersplenism ITP Leukemia Prosthetic heart valve Recent transfusion
BLEEDING TIME high
Platelet dysfunction DIC Leukemia Liver disease Thrombocytopenia Von Willebrand’s Vasculitis
PROTHROMBIN TIME
Measures vitamin K dependent clotting ability, and extrinsic pathway
Used to screen for bleeding disorders
Used to monitor patients on warfarin*
The International Normalized Ratio (INR) has been introduced to reduce inter lab variability in reporting PT
PROTHROMBIN TIME high
Anti-phospholipid antibody syndrome DIC Liver disease Vitamin K deficiency Factor II, V, VII, or X deficiency
ACTIVATED PARTIAL THROMBOPLASTIN TIME (PTT)
measure of the time taken for a clot to form in citrated blood following the addition of calcium and a phospholipid platelet substitute.
Measures Effectiveness of the Intrinsic Pathway
Used to work up bleeding disorders
Used to monitor heparin therapy
Screen for lupus anticoagulant
Intrinsic pathway?
Think PTT (partial thromboplastin time) Think VIII, IX, XI, and XII
Extrinsic pathway?
Think PT (prothrombin time) Think II and VII
Thrombin Time
The rate of conversion of fibrinogen to fibrin in the final stage of coagulation as measured by the addition of thrombin to citrated blood.
Measure of Fibrinolytic Pathway
Normal: 15-20 secs
Thrombin Time High
DIC Liver disease Dysfibrinogenemia Paraprotienemia Uremia
Thrombin Time Low
Erythrocytosis
Dysfibrinogenemia
Indications to order coagulation studies
Work-up of suspected bleeding disorders
Screening before major surgery, part of pre-op eval
Monitoring of medications (warfarin, heparin)
Monitoring of bleeding disorders
Monitoring of liver disease
Platelet/cellular deficiency or malfunction:
Gum bleeding Easy bruising Epistaxis Petechiae Prolonged bleeding from minor cuts Abnormal bleeding time, normal PT/PTT
Factor deficiencies (hemophilia)
Hemarthroses Easy bruising Delayed bleeding Postop hemorrhage Muscle hematoma Normal bleeding time, abnormal PTT
