Section 8 Flashcards
Reasons to do hemostasis testing
monitor therapy, ID “coag” defects
manual tilt method
trouble shooting method, not done anymore, hard to tell
Mechanical
two different types
electromagnetic clot detection:
coductivity between two probes
clot finishes circuit
magnetic
increases viscosity
Photooptical (turbometric)
measures change in OD of test sample light transmission
light transmitted
cloudy or turbid samples will change result
nephlemetric
light scatter also immunologic (90-180)
change in light that is scattered
cloudy or turbid will change results
Chromogenic
color producing substrate PNA (YELLOW)
proteins free pNA, color proportional to protease activity
Immunologic end point
latex particles w ab
ab-ag complex aggglutinate, absorb more light
PT Test
Prothrombin Time
Extrinsic path
VIII, X, V, II, I
PPP sodium citrate
neoplastine: heparin inhibitor
phospholipid PF3 substitute
CaCl2 to override sodium citrate
What can PT not test for
Can not test for TFIII, Ca++, PF3/XIII
used to monitor anticoags
Ref range for PT
11-13 seconds
pts on oral anticoags will have PT of 20-27 seconds
INR
international normalized ratio
what does this ratio do?
when on an anticoag….what happens to the magic 4?
protein induced……
“correction” standardizes results between labs
when on an anticoag, magic 4 are not decreased in concentration, they are produced in incomplete forms
Protein induced by VIT K absence PIVKA
PIVKA extras
refrence … given a …., futher from this number means?
refrence thromboplastin assigned a 1, the further the ISI is from 1 the less sensitive it is to PIVKAS
Ref range of INR
TR
.9-1.2 ref range
TR: 2-3
INR calculation
pt PT/normal PT to the power of ISI
APTT
intrinsic
XII, XI, IX, II, I ,V VIII, PK HMWK, X
2 rgnts:
Activator rgnt - contact activator (XI, XII, PK, HMWK)
PF3 sub
CaCl2
APTT cannot test?
used to monitor ….what are these values?
cannnot test PF3, Ca++ or XIII
used to monitor effects of heparin (these pts will have 1.5 -2.5x the normal value)
APTT ref range
26-36 seconds
PT normal APTT prolonged
upper part of intrinsic factor problem
XII, XI, IX, HMWK, PK, VIII
PT prolonged APTT norm
VII
extrinsic path
PT prolonged APTT prolonged
common path I, II, V X
TT
thrombin time
tests adequacy of?
reagent?
ref range
tests adequacy of fibrinogen
time required for clot to form is thrombin time
reagent - dilute thrombin
Ref range: 14- 20 sec
50:50 mix
if a test is prolonged, it is due to…..
mix what two things?
a deficiency result
a inhibitor result
if one test is prolonged, it is due to a factor deficiency or inhibitor
mix norm plasma and pt plasma 1:1
Factor deficiency: addition of norm plasma should cause a significant correctioon in prolonged result
Facotr inhibitor: test should remain prolonged
Immunologic fibrinogen
measures?
quantitates….
measures Ag
quantitates total fibrinogen and dysfunctional
Fibrinogen activity
quantitates?
most?
plasma is? for what reason?
plotted on a
quantitates only FUNCTIONAL fibrinogen
most commonly preformed fibrinogen assay
plasma diluted ot 1:10 minimize heparin
std curve
FDPs
Fibrinogen degradation products
dont differentiate between…will be positive on both
semi quant measure of FDPs
will be pos in presence of FDP, Fibringen fibrin ..etc
dont differentiate 1 from 2 fibrinolysis, will be positive in both firbinogenolysis/fibrinolysis
D-Dimer
only in
what is stabllizied
assays?
seen in cases of?
all assays use?
common?
only present in 2 fibrinolysis
(polymers stabilized by XIII form clot)
ELISA/EFA
SEEN IN CASES OF THROMBOSIS (DIC/DVT/PE)
all assays use monoclonal ab to D-dimer
latex aggl common
Interpretation of D-Dimer
particles agglut if D-dumers are present and change OD, flourescne of visible agg on slide
Be aware of post zone (too much ag) in assay
Factor Assay
using a specific….
if pt is deficient, what do results look like?
ref range
using specific factor def plasma (has everything but VIII) re-run APTT
If pt is def VIII, APTT will remain prolonged
if pt is deficient in some other factor, it will correct
Ref range: 60-150%
Anti Xa assay
monitors what therapy?
1.)pt pl….
2.) add
increased color means?
to monitor therapy w LMWH, UFH or direct facotr Xa inhibitors
1.)pt plasma w rgnt that has constant Xa amount
2.) add chrom substrate
increased color means decreased LMWH,UFH Direct..etc
RT
what does the snake venom do?
acts like?
NOT
what can inhibit it?
Differentiates?
Ref range
snake venm cleaves away fibrinopetpide A
TESTS FOR Factor 1
acts like thrombin on fibrinogen
NOT inhibited by thrombin inhibitors like heparin/autoab (FDPs can inhibit)
Differentiates lack of fibrinogen/inhibitor
Ref range: 16-22 sec
TT prolonged, RT normal
thrombin inhibitor like heparin
TT prolonged, RT prolonged
lack of fibrinogen/FDPs
Urea clot lysis/solubility
adequacy of
what does the test contain?
ref range
Adequacy of XIII
if clot has been stabilized by XIII, clot will remain
If not stabilized it will dissolve
PRP, CA++, Glass tube
Ref range 60-150%
Euglobulin clot lysis
measures
make sure pt isnt experiencing dangerous
monitor pts on
ref range
fibrinolytic capability
make sure pt isnt experiencing dangerous degree of fibrinogenolysis
monitor activity of pt on tPA, strep/urokinase
Euoglobulin fraction, buffer, thrombin/fibrinogen
REF RANGE: >1hr (<4hr)
increased fibrinolutic activity will make it faster
Clotal
measures coag/fibrinolytic capacity
ACT
activated clotting time
whole blood clotting time
POCT to monitor high heparin dose during cardiac surgery
RVVT
Direct activator of X
mixing venom w ca++ and PPP tests the common path
Stypven time
20-30 seconds
