coagulation lab and what it assesses Flashcards
aPTT asses which pathways
intrinsic and final common pathways
aPTT measures the time it takes to form a clot using
phospholipid, calcium, and an activator
aPTT monitors the therapeutic response to which drug?
unfractionated heparin (but NOT LMWH)
normal value of aPTT
25-32 seconds
because the intrinsic pathway is slower than the extrinsic pathway, the normal value of ____ will be longer than the normal value of ___
aPTT will be longer than PT
factors must be reduced more than ___% for a change in aPTT or PT to be observed
30%
which pathways does PT assess
extrinsic and final common pathways
PT measures the time it takes to form a clot using
tissue factor and calcium
PT monitors the therapeutic response to which drug?
warfarin
normal PT value
12-14 seconds
the international normalized ratio (INR) is calculation that standardizes
PT results. its based on the ratio of the patients PT and the standard mean PT
normal INR value in healthy patients
~1
target INR for patients on warfarin
2-3 times the control
which lab guides heparin dosing
ACT
normal ACT value
90-120 seconds
ACT is measured during which times of heparin administration
before, 3 minutes after, and every 30 minutes thereafter
the ACT tends to be more accurate than which other lab in the setting of large heparin doses?
PTT
platelet count measures
the number of platelets but not how well they function
what platelet count increases surgical bleeding risk
<50k
what platelet count increases spontaneous bleeding risk?
<20k
what does bleeding time monitor/evaluate
platelet function and the ability to form a platelet plug
normal bleeding time value
2-10 minutes
which 2 drugs prolong bleeding time
ASA and NSAIDS
what does D-dimer monitor for
fibrinolysis via fibrin degradation products
normal value of d dimer
<500mg/dL
what should be included in your differential if D dimer is increased?
DVT, PE, DIC
R time on TEG, what it represents
6-8m, time to begin forming clot
if R time is suffering, what is the problem area and treatment
problem area is clotting factors and tx is FFP
K time on TEG, what it represents
3-7m, time until clot has achieved fixed strength
if K time is suffering, what is the problem area and treatment?
problem area is fibrinogen and treatment is cryo
alpha angle on TEG, what it represents
50-60s, speed of fibrin accumulation
if alpha angle is suffering, what is the problem area and treatment?
problem area is fibrinogen and treatment is cryo
max amplitude on TEG, what it represents
50-60m, highest vertical amplitude on TEG, measures clot strength
if max amplitude is suffering, what is the problem area and treatment?
problem area is platelets and treatment is platelets +/- DDAVP
a60 on TEG and what it represents
max amplitude (MA) minus 5, represents highest verticle amplitude 30m after max amplitude
if a60 on TEG is suffering, what is the problem area and treatment?
problem area ix excess fibrinolysis and treatment is TCA or ACA
