SPECIAL EVALUATION FOR COAGULATION DISORDERS Flashcards
reptilase is an enzyme found in the venom of
bothrops atrox
this enzyme is Capable of converting fibrinogen to fibrin and is unaffected
by heparin
REPTILASE
Helpful in testing for functional fibrinogen
when the thrombin time is prolonged because of heparin.
reptilase time
REPTILASE TIME has the same function as
thrombin
both __ and __ time will be PROLONGED when the level of fibrinogen is decreased
reptilase time and thrombin time
conditions wherein a level of fibrinogen is normal but not functional
dysfibrinogenemia
a treatment for thrombolytic agent and used in treatment with Myocardial infarction and bleeding? thrombosis to dissolve the clot
streptokinase therapy
substances released during fibrinolysis
fibrin degradation products
cases wherein reptilase time is increased or prolonged
dysfibrinogenemia
streptokinase therapy
fibrin degradation products
Reference range of reptilase time
10-15 seconds
explain why reptilase time increase in the presence of FDP
there’s a lysis of fibrin
Specimen for reptilase time
citrated plasma
Testing should be performed within how many hours in reptilase time
within 4 hrs
if the testing for reptilase time can’t be conducted immediately, what is the correct temperature to store the sample?
freeze specimen at -20*C
principle behind reptilase time
Reptilase is added to plasma ,it act by releasing fibrinopeptide A from the fibrinogen molecule, The resultant
monomers polymerize end to end ,forming a clotq
in reptilase time ,
Reptilase is added to plasma ,it act by releasing ___ from the fibrinogen molecule,
fibrinopeptide A
aside from the fibrinopeptide A that is released by fibrinogen molecule induced by reptilase, what is the other one being released?
fibrinopeptide B
this 2 test is to assess the function of Fibrinogen
reptilase time and thrombin time
ristocetin cofactor assay evaluates what
evaluate the function of von willebrand factor and assess if the patient has vWb disease
ristocetin alone is used before as a treatment for?
staphylococcal infection
reference range of ristocetin cofactor assay
60-180 %
specimen of choice for ristocetin cofactor assay
platelet rich plasma
plasma may be refrigerated up to how many hours prior to testing for ristocetin cofactor assay?
up to 8 hrs
in ristocetin cofactor assay, if the test can’t be performed immediately, we must store the specimen to __
-20*C up to 8 weeks
PROCEDURE for ristocetin cofactor assay
a blood sample is collected from the patient and the platelet-rich plasma is isolated
ristocetin is added to plasma. If von willebrand factor is functioning normally, it will bind to the plt glycoprotein (GP1B) receptor and cause platelet aggregation in ristocetin
Normal von Willebrand Factor
Activity
if the von willbrand factor in the patient’s plasma is functioning properly, ristocetin will induce normal platelet aggregation
Decreased or Absent Aggregation interpretation in ristocetin cofactor assay
deficiency or dysfunction of von willebrand factor, which is characteristics of von willebrand disease
The ristocetin cofactor assay is particularly sensitive
for ______, where there is an
abnormal interaction between
vWF and platelets
Type 2B von Willebrand
disease
If the test results show 25 % ristocetin cofactor activity repeat the test using the ___
The final result would then be divided by2
undiluted plasma
Duckert’s Assay is called as
5m urea solubility test
Duckert’s Assay/5M Urea Solubility Test
also known as
factor XIII assay
Used to check for stability of clot
Duckert’s Assay/5M Urea Solubility Test/FXIII assay
Stable Clot in Duckert’s assay means
normal factor XIII activity - the clot remains intact after 24hrs in 5M urea
dissolved Clot in Duckert’s assay means
deficiency in factor XIII activity - the clot was been dissolved within 24hrs in 5M urea, which means the fibrin strands are not being properly cross-linked and stabilized
In duckert’s assay, if the 5M urea is not available, what are the other alternatives?
1% monochloroacetic acid
2% hydrochloric acid
specimen of choice for fletcher factor assay
citrated platelet-poor plasma
fletcher factor assay is used to check for __
pre kallikrein
specimen for fletcher factor assay
citrated platelet poor plasma
deficiency in fletcher factor assay will cause prolonged ___
prolonged APTT
remember PT-EX and PTT-IX
prothrombin is for extrinsic
partial thromboplastin time is for intrinsic
since fletcher factor is in intrinsic pathway, the one that will be prolonged in PTT
are all patients with deficiency in fletcher factor exhibits bleeding?
not all patients, some may not and asymptomatic
reagent for fletcher factor assay
aptt reagent, CaCl2
in fletcher factor assay, the sample must be incubated for how many minutes
10 mns
if there’s a deficiency in fletcher factor, the APTT will become normal after 10 mn incubation
true or false
true
AGAROSE PLASMA GEL TECHNIQUE is used to assess ___
factor VIII inhibitors
specimen of choice for AGAROSE PLASMA GEL TECHNIQUE
citrated platelet poor plasma
reagent for AGAROSE PLASMA GEL TECHNIQUE
control plasma and CaCl2
Agarose contains __ is poured on a plate
fresh normal plasma
result in agarose plasma gel technique that means no inhibitors of factor VIII
cloudy or opaque wall shows due to fibrin clot
result in agarose plasma gel technique that means a presence of inhibitors of factor VIII
clear zone around the well
aside from inhibitors of factor VIII, we are checking ___ as well in agarose plasma gel technique
lupus anticoagulant
effect if there’s factor VIII inhibitors
both PT and aPPT are prolonged
AGAROSE PLASMA GEL TECHNIQUE also used to differentiate ___
deficiency in clotting factor or just an inhibitor
specimen of choice for bethesda inhibitor assay
citrated platelet poor plasma
reagent in bethesda inhibitor assay
factor VIII and control
procedure for bethesda inhibitor assay
PPP is mixed with known amount of Factor VIII and incubated at 37 C for 2 hours
two assay that evaluates factor VIII inhibitors
bethesda inhibitor assay and agarose plasma gel technique
Result: expressed in Bethesda units (1 Bethesda unit means _____ of Factor VIII is inhibited)
50%
when do we perform mixing studies
if the PT or PTT are prolonged
Mixing Study is also called as
substitution test
purpose of mixing study
to know if the patient’s problem is inhibitors or clotting factor deficiency
coagulation factor that our normal plasma has
all coag factors
how to make substitution reagent
look for 20 individual with normal coag factors