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28 Cards in this Set
- Front
- Back
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Bleeding Time
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Only to screen for platelet disorders or vWD
Affected by platelet count & function |
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PFA-100
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platelet disorder screening
meaures the time acquired for anticoagulated blood to occlude a standard aperture Affected by platelet count & function |
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Platelet aggregometry
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>60% platelet aggregation in response to platelet agonists: ADP, Collagen, Epi, ristocetin, arachodonic acid
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Platelet aggregrometry - biphasic curve
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low dose ADP & epi from primary & secondary wave (degranulation)
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platelet aggregometry - monophasic curve
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high dose ADP, collagen & ristocetin
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platelet aggregometry - abnormal - medication
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Aspirin - decreased aggregation with arachidonate
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platelet aggregometry - poor response to all agents except ristocetin
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Glanzsmann's thromboasthenia
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platelet aggregometry - poor response only to ristocetin
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Bernard Soulier (anemia, lg plts, tcp) & vWD
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platelet aggregometry - absent secondary phase (epi & ADP)
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storage pool deficiency & ASA
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platelet aggregometry - poor response to epi
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myeloproliferative disorders
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Clot retraction test
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Normal produce clot retraction within four hours
Glanzmann's thromboasthenia - diminished clot retraction |
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Platelet antigens detected by flow
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GPIIb/IIIa - glanzmann's
CD62-alpha granule when present CD63 Fibrinogen when bound to GPIIb/IIIa |
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ACT
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point of care testing
heparin >400s whole blood - affected by plts, hematocrit Can use anti-Xa if need to |
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elevated PTT
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Intrinsic pathway (F12, F11, F9, F8) or common pathway (FV, FX, F2, F1) or inhibitor
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prolongation of both PT & PTT
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common pathway (FX, FV, F2 or F1) Or an inhibitor
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Shortened PTT - by what factor
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elevated F8
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PTT monitors what drugs
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heparin, hirudin, argatroban
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Heparin resistance
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acute phase response (inc F8 & binding of heparin) or antithrombin deficiency.
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Mixing study - adding aged plasma
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Aged plasma lacks F2, F5, F8, F`13
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Mixing study - adsorbed plasma
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Adsorbed plasma lacks-F2,F7,F9,F10
(vit k dependent) |
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Mixing study - serum
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Serum lack fibrinogen, F2,FV,F8,F13
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PF4
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platelet factor 4 can artificially shorten PTT
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Activated Protein C Resistance
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Factor V Leiden mutation - point mutation glutamine for arginine at cleavage sites = FV resistant to protein C
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Anticardiolipin Antibody (ACA)
IgG, IgA, IgM |
have either ACA (Elisa) or LAC
80% antiphospholipid syndrome have ACA ACA testing w/Beta2 glycoprotein I manner - antibodies to cardiolipin bound to Beta2 glycoprotein i Syphilis, Q fever, HIV - false positive ACa (IgM) ACA false positive RPR |
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Clot stability test (urea solubility test)
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F13 generates covalent bonds
5M urea - pts w/ 1-2% F13 activity clot stable for 24 hrs - detects homozygotes Fibrinogen is qualitatively & quantitatively normal |
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D-dimer
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fibrin degredation product
formed only by plasmin degredation of fibrin fibrin formed then degraded DIC, thrombosis, bleeding, cirrhosis, mucin secreting adenocarcinomas |
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What does D-Dimer tell us
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normal = excludes ongoing in vivo thrombus (DVT, PE)
Low probablity |
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D-Dimer Assays
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Latex agglutination, serial dilutions (semiquantitative)
ELISA - quantitative |
