LAV EVAL - PRIMARY HEMOSTASIS Flashcards
test under the plt aggregation test
epinephrine
collagen
adp
ristocetin
test for plt adhesiveness
salzman
test for retraction time
hirschboeck
macfarlene
stefanini-dameshek
test for bleeding time
duke’s
ivy’s
serves to immediately limit bleeding through the formation of a platelet plug
primary hemostasis
platelets play a key role in the rapid response to blood vessel by
adhering to the endothelial wall at the site of injury
releasing potent anticoagulant compounds
aggregating to form a plug
providing a phospholipid surface for activated coagulation enzyme complexes
defects in primary hemostasis are generally associated with ____ bleeding
mucocutaneous bleeding
mucocutaneous bleeding is characterized by __
epistaxis, ecchymosis, genitourinary or gingival bleeding
A typical patient with defective primary hemostasis might
experience profuse bleeding from small cuts and require the
application of pressure for a prolonged period to stop the
bleeding
true or false
true
LABORATORY METHODS FOR THE STUDY OF
HEMOSTASIS
tests for primary hemostasis
tests for secondary hemostasis
test for inhibitors of coagulation (circulating anticoagulants )
what are the Tests for primary hemostasis
- Bleeding Time
- Platelet Count
- Tests for specific platelet functions
- Clot Retraction Time
- Capillary fragility or capillary resistance test
this test for primary hemostasis provides assessment of platelet count and
function
bleeding time
it measures plt plug formation
bleeding time
factors that affect the bleeding time
elasticity of cut tissue
ability of the blood vessel to contract and retract
mechanical and chemical action of plt in the formation of the hemostatic plug
Methods of Bleeding Time Determination
duke’s method
modified ivy’s method
coply lalitch method
adelson-crosby method
macfarlane’s method
aspirin tolerance test
best method to assess platelets. It is considered to be the best screening
test available for platelet’s role in hemostasis.
Modified Ivy’s Method
Both methods involve
immersion of the wound finger
in a sterile NSS warmed at 37̊C
until bleeding stops
coply lalitch method
adelson-crosby method
same principle with Adelson-Crosby method but it only uses ear lobe as the site of
puncture
macfarlane’s method
assesses the effect of a
standard dose of aspirin on the Duke’s Bleeding Time
aspirin tolerance test
ref range for duke’s method
1-3 mns
ref range for modified ivy’ method
3-6 mns
template method ref range
3-6 mns
coply lalitch method ref range
170-340 seconds
Adelson-Crosby Method (NV:__ seconds)
170-340
the 3 method of assessing bleeding time that has the same normal values
copy lalitch method
adelson crosby method
macfarlane’s method
170-340 seconds
factors that causes with prolonged bleeding time:
when plt are reduced
injury of capillary wall
prothrombin deficiency
slightly prolonged in severe anemia
conditions whereas plt are greatly reduced causing prolonged bleeding
thrombocytopenia purpura
acute leukemia
aplastic anemia
conditions whereas the capillary wall are injured causing prolonged bleeding
scurvy
toxins (infection, chemical, snake venom)
conditions wherein there’s prothrombin deficicency are injured causing prolonged bleeding
destructive disease of the liver
hemolytic disease of the newborn
Direct Methods for platelet count
guy and leake method
rees and ecker method
brencher-cronkite method
inDirect Methods for platelet count
fonio’s method
dameshek method
platelets are counted in their relationship to
red cells on a fixed-stained smear
indirect method
This method is NOT
RELIABLE because the results depend upon the distribution of platelets and on the red cell count
indirect method of counting PLT
reagents used in Fonio’s method
14% MgSO4 + 1ggt of blood + Wright Stain.
reagents used in dameshek method
Brilliant Cresyl Blue, Sodium Citrate,
sucrose and formalin; counter stain with Wright’s Stain.
indirect method plt counting formula
plt/ul = plt X rbc count/1000
platelets are counted in a
hemocytometer as in erythrocytes and leukocyte
direct method
guy and leake’s solution component
diluent is made of sodium oxalate,
40% formalin and crystal violet.
formula for guy and leake
Platelets/uL= platelet counted X 5 X 10 X 10
rees and ecker solution components
diluent is made up of sodium oxalate, brilliant cresyl blue, formalin and distilled water
calculation for rees and ecker
Platelets/uL=
Platelets counted X 10 X 200
divide by 4
this method of counting plt is when red cells must first be removed
from whole blood, either by sedimentation or by
controlled centrifugation
electronic method
Electronic Method has 2 ways of counting
voltage-pulse counting
electro-optical counting
test for adhesion of platelets
borchgrevink method
salzman method
- platelets are enumerated in the capillary blood
oozing from a bleeding time puncture
borchgrevink method
it is expressed as a percentage of the venous plt count
borchgrevink method
test for the retention of plt within glass beads columns
salzman method
venous blood is aspirated directly from the bein through a bead column and into a vacutainer
salzman method
platelet aggregation test
employs the use of various __
aggregometers
measures the changes in optical density of a
platelet suspension under conditions of
constant temperature and continuous
agitation
platelet aggregation test
platelet aggregation test is studied in suspensions of __
citrated plasma
(PRP)
why do we perform plt aggregation test
evaluation of suspected hereditary and acquired
disorders of platelet function
. Hereditary platelet function disorders include
❑ Defects of adhesion (Bernard Soulier syndrome)
❑ Defects of aggregation (Glanzmann
thrombasthenia)
❑ Defects of secretion (Alpha or Dense Granule Deficiency, Aspirin-Like Defects).
Acquired platelet function disorders
❑ drug-induced platelet dysfunction (aspirin,
clopidogrel, antibiotics)
❑ uremia
❑ myeloproliferative disorders
depends on normal number of contractile
platelets, the presence of calcium and ATP,
and a normal concentration of fibrinogen
Clot Retraction Time
Methods under clot Retraction time
- Hirshboek Method or Castor Oil Method
- Stefanini Method
- Macfarlane Method
Platelet deficiency
a. Thrombocytopenia
give the clot characteristics
clot nonretractile or retracts poorly
Platelet deficiency
b. Thrombasthenia
give the clot characteristics
clot edematous/friable
Afibrinogemia
give the clot characteristics
blood does not clot
Fibrinogenopenia
give the clot characteristics
clot is normal, increase red cell fall out
Increase in Blood Constituents
a. Thrombocythemia
b. Polycythemia
give the clot characteristics
defective retraction, clot flabby/friable
increased red cell fall out
Hyperproteinemia
give the clot characteristics
layered clot
clot may not retract or may retract poorly
rapid sedimentation of red cell
- tests the stability of the small blood vessels to
retain the red cell in their lumen under conditions of
stress and trauma
capillary fragility or capillary resistance test
. Tourniquet or Rumpel –
Leede or Hess Test
by partially obstructing the venous blood, the
capillary pressure is increased and will give rise to
intravasation of blood
which will be manifested in the form of small
hemorrhage called
petechiae
1+ of petechiae in qualitative interpretation
few petechiae on the anterior part of forearm
quantitative interpretation of 1+ petechiae
0-10
2+ qualitative interpretation of petechiae means
many petechiae on the anterior part of the forearm
2+ quantitative interpretation of petechiae means
10-20
3+ qualitative interpretation of petechiae means
multiple petechiae over the anterior and the back of the hand
3+ quantitative interpretation of petechiae means
20-50
4+ qualitative interpretation of petechiae means
confluent petechiae over the anterior and the back of the hand
4+ quantitative interpretation of petechiae means
> 50
this method has positive pressure technique
tourniquet or rumpel
this method has negative pressure
suction cup or petechiometer method
- employs the use of a modified da Silva Melle
instrument
Suction Cup or Petechiometer Method
the cup is applied to the surface of the arm for a
period of one minute at 200 mmHg
Suction Cup or Petechiometer Method
the resistance of the capillaries is expressed as the
least negative pressure required to produced
macroscopic petechiae
Suction Cup or Petechiometer Method
ref range of Suction Cup or Petechiometer Method
less than 4 petechiae
Indications of Increase Capillary
Resistance Test
- Thrombocytopenia
- Thrombocythemia
- Vascular purpura
- Scurvy
- Senile purpura
