[LAB] Hemostasis Lab Testing (Part 2) Flashcards
What test is designed to detect qualitative platelet abnormalities and is used on patients with symptoms of mucocutaneous bleeding?
Platelet function test
How much platelet count indicates the presence of bleeding symptoms?
> 50,000/µL
- “obsolete”
- original test of platelet function
Bleeding time
Reference interval of bleeding time.
2-9min.
What affects the bleeding time procedure?
- intracapillary pressure
- skin thickness
- size and depth of the wound
- high complexity test
- used to detect platelet adhesion, aggregation, and secretion
platelet aggregometry
How much PRP will you add to the cuvette in the platelet aggregometry procedure?
500µL
How many minutes will you incubate the PRP in platelet aggregometry at 37℃?
5min.
True or False.
As platelet aggregates form, more light passes through the PRP.
True (↑ light transmittance)
What is the principle used in whole blood platelet aggregometry?
electric impedance
What is the principle used in PRP platelet aggregometry?
light-transmittance
What is the dilution ratio for specimen and normal saline on whole blood platelet aggregometry?
1:1
Suspension volume range used on whole blood platelet aggregometry.
300-500µL
True or False.
The rise in impedance is directly proportional to platelet aggregation.
True
What happens when platelets adhere to the electrodes and one another during aggregation on whole blood platelet aggregometry?
it will impede the current
What aggregometry is used for the simultaneous measurement of platelet aggregation and secretion of ATP from activated platelet granules?
Platelet lumiaggregometry
How many aliquots of the sample will you use in platelet lumiaggregometry?
2 aliquots
What will you add to the first sample during platelet lumiaggregometry?
ATP and luciferin-luciferase
What will you add to the second sample during platelet lumiaggregometry?
agonist and luciferin-luciferase
Identify the VWF Assay.
- reflect VWF activity rather than concentration and offer improved precision when compared to the VWF: Rco
Manual ELISA
Identify the VWF Assay.
- uses monoclonal antibody specific for an active VWF epitope
VWF activity immunoassay
Identify the VWF Assay.
- mimics VWF’s in vivo collagen adhesion property
VWF collagen binding assay
- Aggregation assay that measures platelet activation and secretion induced by HIT Ab in the presence of heparin.
- reference and confirmatory method for HIT
carbon 14 serotonin release assay (C-SRA)
What is the agonist used in aggregation-based tests?
Unfractionated heparin (UFH)
What indicates the ↑ plasma level in PF4?
thrombotic stroke or coronary thrombosis
What is used in PF4 immunoassays to prevent in vitro platelet activation?
CTAD tubes
Identify the platelet activation marker.
- an active product of the eicosanoid pathway
thromboxane A2
Identify the platelet activation marker.
- stable, measurable plasma metabolite from Thromboxane A2
Thromboxane B2
Identify the platelet activation marker.
- used to characterize in vivo platelet activation
- uses a random urine sample
- maybe used to monitor aspirin therapy and to identify cases of aspirin therapy failure
11-dehydrothromboxane B2
What is the first in vitro clot procedure?
Lee-White whole blood coagulation time test
What is modified version of Lee-White procedure that uses a particulate clot activator in the test tube that speeds the clotting process?
Activated clotting time (ACT) test
What test is used as a point-of-care assay to monitor UFH therapy in high-dose applications?
Activated clotting time (ACT) test
Enumerate the components of PT reagents (thromboplastin).
- affinity-purified tissue factor
- phospholipids
- buffered 0.025M calcium chloride (CaCl2)
What is the specimen used for prothrombin time assay?
platelet-poor plasma (PPP)
The volume of PPP used in PT assay.
50 or 100mL
Premeasured volume of reagent used in PT assay.
100 or 200mL
PT reference range.
12.6-14.6 seconds
True or False.
Reporting PT assays should be at nearest tenth of second.
True
- used to monitor the effects of UFH
- detect LAC-specific coagulation factor antibodies
Partial Thromboplastin Time
Enumerate PTT reagent components.
- phospholipid
- negatively charged particulate activators
Reference interval of PTT.
26-38 seconds
Typical therapeutic range when monitoring heparin therapy with PTT.
60-100 seconds
Identify the anticoagulant.
- nonspecific inhibitor used in PTT mixing studies.
- signals a potential thrombotic risk
Lupus anticoagulant
What assay uses the principle whereby it cleaves fibrinopeptides A and B from plasma fibrinogen to form detectable fibrin polymer?
Thrombin Clotting time
How much thrombin is transferred into the PPP aliquot during thrombin clotting time?
200mL
Reference interval for thrombin clotting time.
15-20 seconds
- isolated from the venom of Bothrops atrox
- catalyzes the conversion of fibrinogen to fibrin
Reptilase
Reptilase only cleaves _____ from the ends of the fibrinogen molecule.
fibrinopeptide A
- an assay that is useful for detecting hypofibrinogenemia and dysfibrinogenemia
Reptilase time assay
- from the Daboia russelii viper that triggers factor X
- “Stypven time”
Russell Viper Venom
