Sunday, March 31, 2019

Measuring extrinsic, intrinsic and common pathways

PT measures extrinsic and common pathways, is sensitive to low levels of Factors 7,10, tissue factor

intrinsic pathway - includes factors 8,9,11,12 also prekallikrein
PTT is elevated if deficient factors 8,9, also SLE, heparin tx
PTT is low in hypercoagulable state

Common pathway includes Factors V, X, prothrombin and fibrinogen

VWB disease- VWF depends on ristocetin induced aggluctination, decreased Factor 8, False positive occurs in inflammation, pregnancy, estrogen therapy

Vitamin K dependent factors decreased by coumadin include : extrinsic
prothrombinm F VII, F X   but not VIII,XI, XII

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