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
this test is superior in sensitivity and specificity as compared with the conventional FDP assay
latex d dimer assay
this test is positive in early DIC and is specific for cross-linked D-Dimer fragment of fibrin
latex D-Dimer Assay
a test to determine if there’s still ongoing or remaining clot in the individual
latex d dimer assay
this test detects for residual clot for patients who had MI and stroke
latex d dimer assay
latex d dimer assay also evaluates
abnormal clot formation and breakdown such as deep vein thrombosis, venous thromboembolism, pulmonary embolism
specimen we can use for latex D-Dimer assay
fresh citrated/heparinized/edta plasma
Serum
2 methods of assay for latex D dimer assay
enzyme immunoassay
latex bead
a low and sensitive assay for latex d dimer assay
enzyme immunoassay
a rapid, simple method of semi quantitative test for latex d dimer assay
latex bead
ref range for latex d dimer
less than 200 ng/ml should be present
conditions where they turn positive result in latex d dimer assay
DIC
pulmonary and cerebral embolism
phlebitis
thrombosis
sickle cell disease
test that detects the presence and QUANTITY of FDP
fibrin degradation products immunoassay
FDP immunoassay is used to evaluate conditions such as
blood clot formation and breakdown as seen in conditions associated with
DIC
thromboembolic disorder
post-surgical states
plasma concentration of TPA ant9igen may be estimated by
enzyme immunoassay
to measure TPA activity, a specified concentration of reagent ____ is added to the patient plasma
plasminogen
TPA levels may indicate increased risk to what conditions
myocardial infarction
stroke
deep vein thrombosis
used to measure PAI I
plasminogen activator inhibitor 1 assay
PAI 1 will inhibts
TPA and urokinase
plasminogen activaor inhibitor 1 assay is done by
collecting blood in acidified citrate tube
centrifuge immediately and create PPP
PPP is mixed with a measured amount of reagent TPA
the methods for the assay of these fragments are based on red cell hemagglutination inhibitors, staphylococcal agglutination and immunodiffusion
quantitative assay of fibrin-fibrinogen degradation products
a new assay that is sensitive biological marker of thrombin generation and X activity because generation of F12 precedes thrombus formation
prothrombin fragment 1.2 test
small protein fragment produced when the prothrombin factor 2 is cleaved by the activated factor 10 during the conversion of prothrombin to thrombin
factor 1.2
use of prothrombin fragment 1.2 test
detects hypercoagulable states
monitoring anticoagulant therapy (direct oral/heparin)
marker of thrombotic events
the FDP present in the patient’s serum neutralized antifibrinogen antiserum, thereby preventing the antiserum from agglutinating fibrinogen-coated erythrocytes
tanned red cell hemagglutination inhibition immunoassay
interpretation of result in tanned red cell hemagglutination inhibition immunoassay
with agglutination - no FDP
without agglutination - with FDP which neutralizes the antiserum
antithrombin inactivates
thrombin and activated factor Xa
natural inhibitor of coagulation/thrombin
antithrombin
in the absence of ___ plasma antithrombin process is relatively slow
and it can act instantaneously inactivates thrombin, otherwise
heparin
this activity test will detect abnormalities of both decreased levels of normal molecule/and or normal amounts of an abnormal molecule
plasma antithrombin test
antithrombin protects ___
from clotting too much
if antithrombin levels are low, a person will have a tendency to ___
clot more easily
if antithrombin levels are too high, a person could, theoretically, have a
bleeding tendency
it measures the availability of functional fibrinogen
plasma thrombin time
a sensitive test in detecting heparin inhibition
plasma thrombin time
prolonged thrombin time is observed in what conditions
hypofibrinogenemia or afibrinogenemia
DIC
specimen for plasmathrombin time
citrated plasma stored at 2-8*C performed within 4 hrs
a measured amount of thrombin is added to plasma. the length of time for a fibrin clot to form is recorded as
thrombin time
whenever thrombin is used, ___ glassware and pipets should be employed
plastic or siliconized
is a series of test ised t9 detect lupus anticoagilant in the blood
lupus anticoagulant
autoantibodies that interfere with blood clotting mechanism
lupus anticoagulant
lupus anticoagulant is commonly found in patient with
Antiphospholipid syndrome
an autoimmune disorder causing abnormal clotting and pregnancy complication
Antiphospholipid syndrome
when are we performing LA test
when there is an explained thrombosis in a vein or artery
and
if there is always a miscarriage
a technique or method used in lupus anticoagulant test since it’s crucial and needs high risk therapy
schleider’s method
helps in investigating the cause of a blood clot
LA test
it evaluates a prolonged partial thromboplastin time and help determine the cause of recurrent miscarriages, or as part of an evaluation for antiphospholipid syndrome
LA test
is LA test used to diagnose the chronic autoimmune disorder SLE
no po
therapeutic anticoagulants
heparin
coumadin (warparin, dicoumarol)
aspirin
works by enhancing the activity of antithrombin III
heparin
heparin is administered throuh
intravenously
causes immediate inhibition of blood clotting
heparin
monitored using the PTT test
heparin
accelerates the action of ATIII to inactiate thrombin
heparin
used in MI and in surgery to prevent clotting
heparin
coumadin (warfarin, dicoumarol) is administered through
orally
takes couple of days for effects to show
coumadin
inhibits production of vitamin K dependent and protein C and S
coumadin
monitored using the PT test
coumadin
for a long term prevention and treatment of clots
coumadin
administration results in irreversible inhibition of PLT cyclooxygenase which is needed for proper PLT aggregation
aspirin
affects last for the lifetime of the PLT at least seven days
aspirin
patients taking aspirin must refrain from intake before test for at least how many days
7 days
