Camille Renee
Dr. M.C.
PHSL1 2122 STV
 Used to measure the function of the extrinsic
pathway of the coagulation cascade
 Assesses vitamin K status, liver damage, and
monitors warfarin therapy
 Method: blood plasma is centrifuged and
tissue factor III is added
 Used to measure the function of the intrinsic
pathway of the coagulation cascade
 Also used to assess heparin therapy
 Method: blood sample is collected and
phospholipids, calcium, and an activator are
added
 Termed ‘partial’ because tissue factor III is
not added to the mixture
Prothrombin Time (PT)
Partial Thromboplastin
Time (PTT)
 Measures extrinsic
pathway
 Normal: 10-15
seconds
 Used to assist with
diagnosing clotting
disorders
 Monitors warfarin
therapy
 Measures intrinsic
pathway
 Normal: 25-40
seconds
 Used to assist with
diagnosing bleeding
disorders
 Monitors heparin
therapy
Question
On your rotation in the intensive care unit, you follow a
patient with advanced sepsis from a central line
infection. On exam you notice marked petechiae on his
extremities as well as some large clots around his
mouth. Concerned about disseminated intravascular
coagulation, you check his labs. What would you
expect?
a) High platelets, low bleeding time, high PT, high PTT
b) Low platelets, high bleeding time, high PT, high PTT
c) Low platelets, high bleeding time, low PT, high PTT
d) Low platelets, low bleeding time, high PT, high PTT
e) Low platelets, low bleeding time, low PT, low PTT
 Platelets. C. M. (2014). PHSL1 2122 STV. Saint James School of Medicine.
 Prothrombin time. Wikipedia. (2014). Retrieved from
http://en.wikipedia.org/wiki/Prothrombin_time
 Partial thromboplastin time. Wikipedia. (2014). Retrieved from
http://en.wikipedia.org/wiki/Partial_thromboplastin_time
 Wikipedia. (2014). Prothrombin time. [Web Image]. Retrieved from
http://upload.wikimedia.org/wikipedia/commons/thumb/2/25/Fibrin-
nach-Thromboplastin.jpg/230px-Fibrin-nach-Thromboplastin.jpg
 Cleveland Clinic. (2009). Pulmonary embolism. [Web Image]. Retrieved
from
http://my.clevelandclinic.org/ccf/media/Images/heart/ptinr_test.jpg
 Dentalcare.com. (2014). Dental management of patients with bleeding
disorders. [Web Image]. Retrieved from
http://media.dentalcare.com/images/en-US/education/ce319/diag02-
coagulation.gif

Prothrombin and Partial Thromboplastin Time

  • 1.
  • 2.
     Used tomeasure the function of the extrinsic pathway of the coagulation cascade  Assesses vitamin K status, liver damage, and monitors warfarin therapy  Method: blood plasma is centrifuged and tissue factor III is added
  • 4.
     Used tomeasure the function of the intrinsic pathway of the coagulation cascade  Also used to assess heparin therapy  Method: blood sample is collected and phospholipids, calcium, and an activator are added  Termed ‘partial’ because tissue factor III is not added to the mixture
  • 5.
    Prothrombin Time (PT) PartialThromboplastin Time (PTT)  Measures extrinsic pathway  Normal: 10-15 seconds  Used to assist with diagnosing clotting disorders  Monitors warfarin therapy  Measures intrinsic pathway  Normal: 25-40 seconds  Used to assist with diagnosing bleeding disorders  Monitors heparin therapy
  • 6.
    Question On your rotationin the intensive care unit, you follow a patient with advanced sepsis from a central line infection. On exam you notice marked petechiae on his extremities as well as some large clots around his mouth. Concerned about disseminated intravascular coagulation, you check his labs. What would you expect? a) High platelets, low bleeding time, high PT, high PTT b) Low platelets, high bleeding time, high PT, high PTT c) Low platelets, high bleeding time, low PT, high PTT d) Low platelets, low bleeding time, high PT, high PTT e) Low platelets, low bleeding time, low PT, low PTT
  • 7.
     Platelets. C.M. (2014). PHSL1 2122 STV. Saint James School of Medicine.  Prothrombin time. Wikipedia. (2014). Retrieved from http://en.wikipedia.org/wiki/Prothrombin_time  Partial thromboplastin time. Wikipedia. (2014). Retrieved from http://en.wikipedia.org/wiki/Partial_thromboplastin_time  Wikipedia. (2014). Prothrombin time. [Web Image]. Retrieved from http://upload.wikimedia.org/wikipedia/commons/thumb/2/25/Fibrin- nach-Thromboplastin.jpg/230px-Fibrin-nach-Thromboplastin.jpg  Cleveland Clinic. (2009). Pulmonary embolism. [Web Image]. Retrieved from http://my.clevelandclinic.org/ccf/media/Images/heart/ptinr_test.jpg  Dentalcare.com. (2014). Dental management of patients with bleeding disorders. [Web Image]. Retrieved from http://media.dentalcare.com/images/en-US/education/ce319/diag02- coagulation.gif

Editor's Notes

  • #2 Used to monitor oral anticoagulant therapy (Warfarin / Coumadin). When a patient who is not taking anti-coagulant drugs has signs or symptoms of a bleeding disorder. When a patient is to undergo an invasive medical procedure, such as surgery, to ensure normal clotting ability.
  • #3 The prothrombin time is most commonly measured using blood plasma. Blood is drawn into a test tube containing liquid sodium citrate, which acts as an anticoagulant by binding the calcium in a sample. The blood is mixed, then centrifuged to separate blood cells from plasma. Tissue factor (also known as factor III) is added, and the time the sample takes to clot is measured optically
  • #7 DIC = increased consumption of factor 7! Disseminated intravascular coagulation (DIC), also known as disseminated intravascular coagulopathy or less commonly as consumptive coagulopathy, is a pathological process characterized by the widespread activation of the clotting cascade that results in the formation of blood clots in the small blood vessels throughout the body. The basis of disseminated intravascular coagulation is excessive consumption of clotting factors and platelets to the point where bleeding can no longer be stopped. Thus you see a paradox of clotting and bleeding in the same clinical picture. The consumption of coagulation factors and platelets leads to prolonged PT and PTT as well as a low platelet count. Bleeding time is determined mainly by platelet count--the fewer platelets, the longer it takes for the platelet plug to be formed, the longer the bleeding time