Lab evaluation of hemostasis Flashcards
Which blood tube is platelet count taken from?
Lavender top
What might a high platelet count mean?
Acute phase reaction Early CML Essential thrombocytosis Polycythemia vera Post-splenectomy
What might a low platelet count mean?
DIC Hemolytic anemia Hypersplenism ITP Leukemia Prosthetic heart valve Recent transfusion
Bleeding time
Measures how well platelets interact with blood vessel walls to form clots.
Used to dx vWD
Bleeding time procedure
make 5mm x 1mm deep puncture
blot q 30 seconds until clot
avoid aspirin 2 weeks prior
Normal is 3 - 8 mins
What might a high bleeding time mean?
platelet dysfxn DIC Leukemia Liver disease thrombocytopenia vWD Vasculitis
Prothrombin Time (PT)
Measures vitamin K dependent clotting ability and extrinsic pathway.
Used to screen for bleeding disorders
used to monitor patients on warfarin
INR normalizes results
PT collection
Light blue top
Fill completely
correct ratio of blood to citrate
Normal PT
PTT: Adults: 11 - 13 seconds
INR: < 2
what might a high PT mean?
anti-phospholipid antibody syndrome DIC Liver disease Vitamin K deficiency Factor II, V, VII or X deficiency.
what does activated partial PT measure?
Intrinsic pathway
VIII, IX, XI and XII
What might high PTT mean?
hemophilia DIC liver disease Vitamin K deficiency Heparin therapy
Thrombin Time
Measure of the fibrinolytic pathway
Rate of conversion of fibrinogen to fibrin.
Normal is 15 - 20 seconds
what might a high thrombin time mean?
DIC Liver disease dysfibrinogenemia paraproteinemia Uremia
what might Low thrombin time mean?
erythrocytosis
dysfibrinogenemia