Lab eval - primary hemostasis Flashcards
DEFECTS IN PRIMARY HEMOSTASIS
o Ecchymosis (bruise)
o Genitourinary bleeding
o Gingival bleeding
- epistaxis
FACTORS AFFECTING BLEEDING TIME
Elasticity of the cut tissue
Ability of the blood vessel to constrict and retract
Mechanical and chemical action of platelets in the
formation of hemostatic plug
Intracapillary pressure
Skin thickness at the puncture site
Size and the depth of the wound
responsible for the adhesion
vWF and GP-Ib
Original test for platelet function
bleedinh time
site of puncture for duke’s method
earlobe or fingern
normal values for duke’s method
1-3 mins
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
NV for MODIFIED IVY’S METHOD
Normal Value: 3-6 minutes
Standardized pressure:
40-60mmHg
NV for COPLEY LALITCH METHOD and ADELSON-CROSBY METHOD
170-340 seconds
puncture depth for COPLEY LALITCH & ADELSON
CROSBY METHOD
6mm deep
Same principle with Adelson-Crosby method but it
only uses earlobe as the site of puncture.
MACFARLANE’S METHOD
Assess the platelet function disorder and resistance of aspirin
ASPIRIN TOLERANCE TEST
NV for ATT
1-3 mins (same with Duke’s method)
Platelets are counted in a hemocytometer as in
erythrocytes and leukocytes.
direct method
diluent of guy and leake is made of
sodium oxalate, 40% formalin and
crystal violet.
Guy and Leake formula
P𝒍𝒂𝒕𝒆𝒍𝒆𝒕𝒔/𝝁𝑳=𝒑𝒍𝒂𝒕𝒆𝒍𝒆𝒕𝒔 𝒄𝒐𝒖𝒏𝒕𝒆𝒅×𝟓×𝟏𝟎×𝟏𝟎0
Rees and ecker also known as
Tocantin’s Method
Diluent of rees ecker is made up of
sodium oxalate, brilliant cresyl blue,
formalin and distilled water
formula for rees and ecker
P𝒍𝒂𝒕𝒆𝒍𝒆𝒕𝒔/𝝁𝑳=𝑷𝒍𝒂𝒕𝒆𝒍𝒆𝒕𝒔 𝒄𝒐𝒖𝒏𝒕𝒆𝒅×𝟏𝟎×𝟐𝟎𝟎 / 5 (divided by 5)
Uses phase contrast microscopy
BRENCHER-CRONKITE METHOD
diluting fluid of BRENCHER-CRONKITE METHOD
1% ammonium oxalate
Platelets are counted in their relationship to red cells on a
fixed-stained smear.
indirect method
Fonio’s method is made up of
14% MgSO4 + 1 drop of blood + Wright stain
