TEST FOR PRIMARY HEMOSTASIS Flashcards
term used to describe the
mechanism of certain systems that keeps blood in the circulation and produces of clot in cases of blood vessel injury
HEMOSTASIS
The systems composing the process of hemostasis are the:
Blood vessels
Platelets
Coagulation factors
Fibrinolysis components
General Considerations in preventing premature activation activation
Contamination with Tissue
thromboplastin
Inappropriate container
Improper Temperature
Hemolysis
EQUIPMENT AND ANTICOAGULANT
Needle Size
Evacuated Tubes/Syringes
NEEDLE SIZE:
_______most commonly
used for coagulation samples
_______collection of more
than 20 mL of blood
_______narrow or small
veins
20-gauge needle
19-gauge needle
21-gauge needles
Syringes and evacuated tubes should be______
SILICONE COATED.
ANTICOAGULANTS:
POTASSIUM CHLORIDE
TRISODIUM CITRATE
EDTA
HEPARIN
preferred anticoagulant
good in preserving the
labile factors______ and _____
TRI-SODIUM CITRATE.
Factor V and VIII
blood-to-anticoagulant ratio
for citrate
9:1
BLOOD COLLECTION:
1. _______is acceptable if tissue juice contamination must
be avoided
2. In anticipation of difficulties while doing venipuncture or if blood is being drawn for special procedures, using a ______ is recommended
- VACUUM TUBE METHOD
- TWO-SYRINGE METHOD
TEST FOR PRIMARY HEMOSTASIS
Bleeding time
Capillary resistance Test
Clotting Retraction Time
Platelet Count
Platelet Aggregation
Platelet Adhesiveness
actual time it takes for a standard wound to stop bleeding
BLEEDING TIME
BLEEDING TIME DETECTS:
Abnormalities of platelet number and function
Von Willebrand Factor deficiency
Abnormalities of vessel wall structure
BLEEDING TIME METHODS
MODIFIED DUKE METHOD
IVY METHOD
Detects abnormality of the capillaries due to a structural weakness in the capillary walls or thrombocytopenia
CAPILLARY RESISTANCE TEST
CAPILLARY RESISTANCE TEST METHODS:
POSITIVE PRESSURE TEST
NEGATIVE PRESSURE TEST
5 mL of whole blood is incubated at 37 deg Celsius for 1 hr
Clot will begin to shrink and retract from the walls of the tube
CLOT RETRACTION TIME/ MCFARLANE CLOT RETRACTION TECHNIQUE
NORMAL VALUE FOR CLOT RETRACTION TIME
44-67%
FORMULA FOR CLOT RETRACTION TIME
%CRT = VOL SERUM/TOTAL VOLUME OF WHOLE BLOOD X 100
FACTORS OF CLOT RETRACTION TIME
1.NUMBER OF CONTRACTIBLE PLTS
2.PRESENCE OF Ca and ATP
3.normal concentration of fibrinogen
PLT count methods
DIRECT & PLT ESTIMATION OF PBS
Direct methods for plt count
TONKANTIN METHODS
BRECKER-CRONKITE METHOD
UNOPETTE METHOD
Aggregation agents are added to PRP to induce shape change and aggregation of platelets
PLATELET AGGREGATION
PLATELET AGGREGATION:
AGGREGATION AGENTS?
Epinephrine
Collagen
ADP
Ristocetin
When blood is passed through a glass bead column, normal platelets that have VWF will adhere and aggregate to the beads
GLASS BEAD TEST
FORMULA FOR PLT ADHESIVENESS
PA=(PC1-PC2/PC1)X 100%
NORMAL VALUE FOR PLT ADHESIVENESS
70% or greater
REFERENCE METHOD for
manual COUNT FOR PLT
BRECKER-CRONKITE METHOD
