Vasc. and plt testing Lecture 2 (continue of 1) Flashcards
Capillary fragility test (tourniquet test)
evals…looking for
fever?
evals vascular integrity looking for petechiae
dengue fever
Components of blood
adult vol?
liquid - water/proteins/plasma
Adult vol: 4-6 liters
EDTA tube
chelates calcium
EDTA clumpers
plt satillites
cold plt ab
Sodium Citrate
binds calcium
must have full tube 1:10
cold plt ab
multiple by 1.1
PPP/PRP
Anticoag sodium citriate
HCT
>55%
>55-65%
>65%
HCT >55% vol of anticoag needs to be adjusted
HCT 55-65% remove .1ml of citrate and do not do calculations
HCT >65% use calculation (do not need to know)
CBC counts
x10
WBC x 10 3
RBC x 10 6
PLT x 10 3
PLT count range
150-400 x 103
CRITICALS:
<30 x103
>1000 x 103
Immature Plt fraction (IPF)
measure of
reflects?
more immature?
used for?
Measure of immature plts in peripheral blood
reflects rna
MORE IMMATURE = more fluorescnense
used for thromobytopenia
Low to normal IPF
decreased production of plts
ex: aplastic anemias, leukemia, BM suppression
Increased IPF
increased destruction
ITP,TTP,DIC drug effects
Bleeding time test
ob
evals…
NOT dependent of
time?
obsolete
evals plt function/# ONLY
NOT dependent of coag cascade
2-9min
Plt function analyzer (PFA)
tests
in
whole
test cartridges…
collagen/…
Tests primary hemostasis in artificial vessel, stim in vivo process of plt adhesion, activation and aggregation
whole blood
tests cartridges w biochem active membranes
Collagen/ADP
Collagen/EPI
Closure time (PFA 100)
screens for…
under capillary flow similar to?
times prolonged with
HCT
PLTs
screens plts for ability to adhere and aggregate under capillary flow similar to in vivo
Times may be prolonged with HCT <35% or plts <150,000
Plts defective/WV disease PFA-100 interpretation
Col/ADP and Col/Epi prolonged
Aspirin/drug PA-100 interpretatations
Col/ADP normal
Col/Epi prolonged
Optical aggregometry (light transmittence)
method
add
blank?
plts…and become… decreases, increases
referance method
add aggreg to PRP
PPP is blank
Plts aggregate and become clearer, decreasing turbidity and increasing light transmittence
Overview of optical aggregometry
what changes?
primary aggregation
re
secondary aggregation
shape changes
primary aggregation - direct aggreg by agent
release rxn
Secondary aggregation mediated bu release rxn
Aggregating agents (plt agonsits)
response varies dependent on agent and concentration
ADP
Biphasic
30% norm subjects show only primary with any concentration
ASPRIN reduces aggregation (see only primary phase)
EPI/NOREPI
Biphasic
30% norm sub only show primary with any conc.
ASPIRIN reduces aggregation (only see primary phase)
Collagen
single phase with a lag phase
Thrombin
biphasic
often only one phase
Arachidonic Acid
Biphasic
Ristocetin
bi…often
primary? no….only slight
Needs what two things to agglutinate
Biphasic often only one phase
primary agglutination no shape change and only slight release rxn
needs VWF in pt plasma/plt need GP IB to agglutinate
Factors affecting plt aggregation
pH
temp
const
time
cuv
pH (8 optimal)
Temp 37
Constant stirring
Time 30 min
Cuvette/stir bar size/shape
patient facotrs affecting plt aggregation
Excersise,stress,obesity,high fat, smoking, diabetes (INCREASE)
Alcohol/aspirin (DESCREASE)
Whole blood aggregometry (impedence)
inc proportional to?
Increase impedence proportional to plt aggregation
Plt luminaggregometry
Cleaver measure of plt secretion, biphasic curve not needed
firefly derived
luminescence proportional to ATP
