what are some of the routine coagulation test?
PT, PTT, D-Dimer, Fibrinogen and Thrombin time
PT stands for what?
Prothrombin Time
PT test is useful for what?
screening deficiencies in factors 2, 5, 7, and 10; factor 1 deficiency may also be
detected; mainly used to monitor coumadin therapy
which pathway does the PT test look at?
extrinsic pathway
what does coumadin work?
inhibits factors 2, 7, 9, and 10 which are all vitamin K dependent factors
causes for prolonged PT tests time?
vitamin K deficiency, liver disease which disrupts coagulant protein production, and
coumadin therapy
International normalized ratio or INR
standardized prothrombin time test results
what is the formula for INR?
patient's PT divided by mean normal PT
International sensitivity index or ISI
the lower the number, the more accurate it is
What is the moderate intensity therapy range for INR?
2.0-3.0 and is used in total hip or knee replacement
What is the high intensity therapy range for INR?
2.5-3.5 and is used in mechanical valve replacement
What is the very high intensity therapy range for INR?
3.0-4.0 and is used when person has a mechanical valve and is having systemic
embolisms despite therapeutic INR in the high intensity range
Activated partial throboplastin time or aPTT
also known as PTT and measures coagulation factors in the intrinsic system; mainly
used to monitor heparin therapy
what does the fibrinogen test look for?
measures clotting time by thrombin
When is a D-Dimer test positive?
only if patient has thrombosis or DIC
why is the D-Dimer test ran?
diagnose Deep Vein Thrombosis or DVT, Pulmonary Embolism or PE, and
Disseminated Intravascular Coagulation or DIC
what is D-Dimer test measuring?
the fibrin degradation product which is protein fragments of fibrolysis made possible by
the enzyme plasmin; only should be present when blood vessels are injured
what is a thrombosis?
a clot inside blood vessels
what is DVT?