Platelets: Lab Tests/Disorders Flashcards
If PLTs is <50 counted on each side, repeat procedure and dilute blood to ___________
1:20
dilute to 1:200 if >500 PLTs counted
Unopette system’s buffer to maintain pH
Sorensen’s phosphate buffer
Antibacterial agent of Unopette sustem
Thimerosal
Which manual platelet count (indirect method) uses Reese ecker fluid
Dameshek (Indirect - Wet Method)
Best indirect manual platelet count method
Olef method
same principle w/ Fonio but blood to diluting fluid ratio is 1:5 instead of 1:3 (Fonio)
Normal blood smear demonstrates ______________ (#) plts/field
8-20
Formula for platelet estimate per uL of blood
Platelet estimate = (average # of PLTs per field) x (20,000)
Normal plt estimate value
200,000 - 400,000/uL
Gold standard to determine platelet function
Platelet aggregation test
Agonists for plt aggregation test
EACTR2A
Epinephrine, ADP, Collagen, Thrombin, Ristocetin, Arachidonic Acid
Most commonly used agonist for plt aggregation test
ADP
produces biphasic aggregation
Normal clot retraction requires ________________
Normal # of functioning plts
Calcium
ATP
Fibrinogen
________ or _________ is responsible for clot retraction
Actomyosin
Thrombostenin
Prolonged bleeding time in Px w/ plt count of >100x10^9/L indicates that platelets are ____________ or a defect of _____________
Impaired in function
Subendothelial factor
Lab tests for primary hemostsis
Platelet count
Platelet aggregation test
Platelet adhesion test
Clot retraction time
Capillary fragility test
Glass bead retention test
Bleeding time
PT determine the ____ and _____ payhway factor deficient
Extrinsic
Common
Specimen used for PT
Platelet poor plasma
Test used to monitor for Warfarin / Coumadin therapy
Prothrombin time
Serves as a sensitive early marker for mild liver disease that can detect factor VII deficiency and Vitamin K deficiency
Prothrombin time
APTT is ysed for determination if ________ and _______ pathway factor deficient
Intrinsic
Common
standard method for monitoring unfractionated heparin therapy
APTT
Test for fibrinogen deficiency
Thrombin time / Thrombin clotting time
Reptilase time also, test for fibrinogen deficiency and abnormality
Test that uses a specimen diluted with Owren’s buffer
Clauss fibrinogen assay
(PPP diluted 1:10 with buffer)
Determines the coagulation factor deficient in the common pathway
Stypven time / Russel viper venom time
Duckert’s test is a screening test for factor ________ deficiency
XIII
Test for INCREASED fibrinolysis
Whole blood clot lysis time
Presence of _______________ indicates that a stable fibrin clot has been lysed
Crosslinked d-dimer
Gold standard for measuring d-dimer
Classic microplate ELISA
A qualitative agglutination immunoassay test for fibrin degradation product (FDP)
Thrombo-wellcotest (Thermo-fisher)
Two physiologic human plasminogen activators
Tissue plasminogen activator - synthesized in vascular endothelial cells (VEC)
Urokinase - produced in the kidney and VEC
TPA and urokinase is inhibited by…
PAI-1 (Plasminogen activator inhibitor-1)
PAI-1 is produced by…
Vascular endothelial cells and hepatocytes
Mechanism of inactivation of PAI-1
Covalent bonding
PAI-1 assay specimen collection tube
Acidified citrate tube (Stabilyte)
(same w/ Tissue Plasminogen activator assay)
