WEEK 10 - lab eval of fibrinolysis and anticoagulant therapy Flashcards
is the enzymatic breakdown of fibrin in blood clots.
fibrinolysis
star of fibrinolysis
plasmin
(including activators and inhibitors) cuts the fibrin mesh at various places, leading to the production of
circulating fragments that are cleared by other proteases.
plasmin
The endogenous plasmin-mediated process of dissolving a formed thrombus is denoted __
fibrinolysis
principle of whole blood clot lysis time
A clot is dissolved as a result of plasmin activity (no plasmin, no dissolution). Normally, this does not
occur in less than 72 hours because of the presence of plasma inhibitors which inactivate plasmin as it forms.
it assesses body’s ability to dissolve a blood clot and assess the fibrinolyutic system that is responsible in breaking clots
whole blood clot lysis time
if the lysis of clot occurs less than 72 hours it suggest that
our fibrinolytic system is enhanced due to certain conditions
conditions that enhance fibrinolytic activity of WBCLT
hyperfibrinolysis
liver disease
malignancy/cancer
systemic disorders
principle of diluted blood clot lysis time
plasmin inhibitors loose activity on dilution. In this method, whole blood is diluted with a buffer solution and clotted by the addition of thrombin. Then the clot is observed to lysis
Three buffer solutions that can be used in DCLT
o Phosphate buffer (PBS) – most common
o Sodium acetate
o Sodium chloride
purpose of diluted blood in DCLT
makes the blood more sensitive and the dilution reduces the concentration of clotting factors and inhibitors (plasmin inhibitors) to be observed readily ng
normal value of DCLT
should not lyse less than 6-10 hrs
shorten lysis suggests
increase fibrinolysis in DCLT observe in conditions such as
DIC - disseminated intravascular coagulation
liver disease
cancer
prolonged lysis time suggest in DCLT
defective fibrinolysis or excessive inhibitions seen in conditions where clot breakdown is impaired
Blood is collected in an anticoagulant, centrifuged and the plasma is recalcified, and checked for clot lysis
PLASMA CLOT LYSIS TIME (PCLT)
steps for plasma clot lysis time
collect blood
centri
recalcified plasma - adding calcium
check for clot formation
observe lysis
incubation
are proteins that can be precipitated when plasma is acidified by 1% acetic acid
euglobulin
fraction of plasma protein
eugloblulin
A screening procedure for the measurement of fibrinolytic activity (overall fibrinolysis).
EUGLOBULIN CLOT LYSIS TIME (ECLT)
euglobulins are fraction of plasma protein which is composed of
plasminogen, plasminogen activator and fibrinogen
normal value of whole blood clot lysis time
lysis after 24 hrs
this test is more sensitive than the clot lysis time
euglobulin clot lysis time
increase fibrinolytic activity of ECLT is seen in
associated with circulatory collapse
adrenalin injection
sudden death
pulmonary surgery
pyrogen reaction
obstetric complication
extreme stress
increased fibrinolytic activity is observed in euglobulin clot lysis time such as the condition associated with circulatory collapse, what are the conditions or example of scenario where it is observed?
shock
circulatory system fail
how adrenalin injection increase fibrinolytic activity
stimulates the release of tissue plasminogen activator which activates plasminogen to become plasmin
in sudden death, why fibrinolysis increased
sudden death - stress and physiologic changes trigger hyperfibrinolysis and is observed in postmortem whereby the body undergo uncontrolled processes
how pyrogen reaction increase fibrinolytic activity
induces systemic inflammation activating fibrinolysis
obstetric complication examples
placental abruption
amniotic embolism
post partum hemorrhage
how extreme stress increase fibrinolytic activity
-stress induces production of catecholamines (adrenalin)
principle of euglobulin clot lysis time
addition of 1% acetic acid to diluted plasma causes the euglobulin portion of the plasma to precipitate
after removing the supernatant, the euglobulin are dissolved in a buffer solution, thrombin is added to order to clot the euglobulins
the clot is incubated at 37*C and the time of complete lysis is noted
if the fibrinogen concentration is less than 80 mg/dl what will happen if we measure the fibrinolytic activity
it will be difficult to measure due to small clot
the test should be set up immediately after collection, plasma should be kept on ____
ice
why do we need to keep the plasma on ice?
the plasminogen activators are labile in RT thus will decrease their concentration
principle of protamine sulfate turbidity test
patient and control plasma are mixed with varying dilutions of protamine sulfate
each tube is incubated at room temp for 30 mns and observed for fibrin strand
a procedure used to detect the presence of fibrin monomerrs
PSTT - Protamine sulfate turbidity test
this FDP assay is not affected by therapeutic level of heparin, a blood thinner/anticoagulant
PSTT - protamine sulfate turbidity test
this test evaluates the FIBRIN DEGRADATION PRODUCTS
PSTT - Protamine sulfate turbidity test
the presence of fibrin degradation products means there’s an ongoing fibrin formation and dissolution, commonly seen in condition such as
disseminated intravascular coagulation
PSTT is a practical, specific, and sensitive blood test for the exclusion of __ and ____
venous thromboembolic disease
disseminated intravascular coagulation
aside from venous thromboembolic disease and DIC, the presence of fibrin monomers is also associated with conditions like
pulmonary embolism
cirrhosis of the liver
it measures a specific fragment arising from the degradation of crossed linked fibrin (d dimer )
latex d dimer assay