Flashcards in Introduction to Hemostasis; Specimen collection Deck (78):
List the four major systems involved in maintaining hemostasis.
Plasma coagulation factors
Process by which the body (upon vessel injury) spontaneously stops bleeding & maintains blood in the fluid state within the vascular system.
Prevents blood loss from injuries by the formation of a thrombus, and re-establish blood flow during the healing process.
The process of clot formation
A blood clot within the vascular system; "platelet plug"
Also refers to the formation of a blood clot or thrombus, but usually considered to be an abnormal finding.
Name of the first system
Name of the second system
Name of the fourth system
Name of the third system
Plasma coagulation factors
Which system is responsible for primary hemostasis?
Platelets (2nd system)
Which system is responsible for secondary hemostasis?
Plasma coagulation factors (3rd system)
Breakdown of fibrin
Reduces blood flow to area of injury to minimize blood loss and also draws platelets close to the injured vessel wall.
Damaged endothelial cells secrete___________.
Von Willebrand (vWF) factor
What is activated by exposure of tissue thromboplastin/tissue factor (TF)?
Plasma coagulation system
Platelet adhesion, aggregation, and, secretion is necessary to form ______
What system is initiated it by TF (tissue thromboplastin)?
Plasma coagulation system/ "cascade"
What three consequences leads to the formation of fibrin?
Coagulation, inflammation, and tissue repair
List two stages of Hemostasis.
Primary and secondary hemostasis
What is the function of primary hemostasis?
Platelets interact with injured vessels (and other platelets) to seal the wound. and form a primary platelet plug.
Does primary hemostasis have short term or long term effect?
Short term - temporarily arrests bleeding
What two systems are associated with primary hemostasis?
Vascular intima and Platelets
What type of test is used to diagnose a defect in primary hemostasis?
What is the function of Hemostasis?
Thrombin generated via coagulation cascade, in turn, generate fibrin. and forms secondary hemostatic plug.
Does secondary hemostasis have short term or long term effect?
Long term- strengthens the platelets plug
What two systems are associated with secondary hemostasis?
Coagulation and fibrinolysis
What type of test is used to diagnose a defect in secondary hemostasis?
Briefly describe an overview of hemostasis... beginning with the initial damage to the blood vessel. and ending with fibrinolysis.
- Collagen exposed/vWF secreted..platelet adhesion
- ADP secreted from granules- platelet aggregation= 1* hemostasis
- platelet plug reinforced by fibrin= 2* hemostasis
- Thrombus dissolved by fibrinolytic system
List 7 types of bleeds associated with a platelet or vascular defect. (problem with primary hemostasis).
Petechiae, Purpura, Epistaxis, Hematemesis, Menorrhagia, Telangiectasia and also mucosal bleeding
List the 3 types of bleeds associated with disorders of coagulation. (problem with secondary hemostasis)
Ecchymoses, and Hemarthrosis, and also delyaed bleeding an dozzing from wounds
Type of bleed that leads to pinpoint hemorrhages from arterioles or venules (no platelets)
Type of bleed that leads to purple discoloration of the skin usually caused by many petechiae (small bruises)
Type of bleed that leads to nosebleeds.
Type of bleed that leads to vomiting blood.
Type of bleed that leads to abnormal, prolonged, menstruation.
Type of bleed that leads to spider like dilations of small blood vessels
Characteristic with disorders of platelets or vessels and causes soft tissue bleeding.
Characteristic with disorders of coagulation
delayed bleeding and oozing from wounds
Type of bleed that leads to very severe bleed (s) into deep tissues/ muscles (large bruises)
Type of bleed that leads to joint bleed (s).
Hemostasis is a combination of ________ & _______
cellular and biochemical events
List two types of mechanisms in Enzyme systems
Coagulation and fibrinolysis mechanisms
This includes vascular intima, platelets, erythrocytes, neutrophils, and monocytes
What occurs when hemostatic systems are out of balance?
Thrombosis or hemorrhage or both may occur
What is the preferred venipuncture method?
Evacuated Tube system (ETS)
List three venipuncture methods.
-Evacuated tube system
-syringe or butterfly/syringe
What is the correct specimen collection and handling requirement for Evacuated tube system?
-Assures correct blood; anticoagulant ratio
-Must have good veins!!!
What is the correct specimen collection and handling requirements for syringe or butterfly/syringe?
-Used with small, fragile veins
- Pose additional needle stick risk when transferring blood into tube
This method is discouraged as heparin contaminates sample and prologs clotting times if not properly flushed.
What is the correct specimen collection and handling requirement for Indwelling catheter?
-Flush line with saline
-Withdraw 5-10 ml blood & discard
-then, collect specimen
What is the most common anticoagulant used?
3.2% Sodium citrate (PT/APTT)
What is the blood:anticoagulant ratio?
9:1 so need a full tube draw
Chelates (binds) free plasma calcium to prevent clotting.
3.2% sodium citrate
Specimen collection and handling requirement for collection tube type- 3.2% sodium citrate
Must be plastic or siliconized glass and mix tube well by gentle inversion--DO NOT shake.
What is the order of blood draw?
-ALWAYS use a non-additive discard tube with a winged needle (butterfly) collection.. "dead space"
- Always draw blue top after a non-additive tube.
Why do we always draw blue top after a non-additive tube?
To prevent contamination with the previous tube's anticoagulant.
EDTA (purple top) also chelates calcium to prevent blood from clotting, but why do we not use EDTA tube to collect blood?
It also binds reagent calcium in clot testing so cannot use!!!
How does increased hematocrit (>55%) affect routine coagulation (PT/APTT)?
- Decreased in plasma vol relative to whole blood decrease the plasma to anticoagulant ratio
- This excess anticoagulant may then bind to the Calcium chloride (added during the testing procedure) to prolong the clotting time.
List four unacceptable specimens
Clotted, hemolyzed, lipemia, under-filled sodium citrate tubes, increased hematocrit
Explain how the clotted specimen will affect routine coagulation testing?
Many factors platelets, and RBCs consumed in clotting. So be sure to gently invert tube after venipuncture (4-6X) to prevent clots
Would clotted specimen be falsely prolong or falsely shorten?
Falsely prolong clotting times
Would hemolyzed specimen be falsely prolong or falsely shorten?
Falsely shortens clotting times
In hemolyzed specimens procoagulant substances released from cells and tissues to ______
Activate clotting pathways
Hemolyzed specimens can be in vitro or in vivo. What causes hemolyzed specimen in vitro?
-Prolonged tourniquet application
-excessive needle manipulation
- mixing blood too vigorously
-forcing blood through a small bore needle
-pulling too hard on a syringe
What causes specimens to be lipemic plasma?
Additional light scatter from lipid droplets gives erroneous results
Would Lipemia specimen be falsely prolong or falsely shorten?
Falsely prolongs clotting times
Why are short draws specimens not acceptable?
If tube is under filled, excess anticoagulant remains in the plasma layer after spinning. This excess anticoagulant may then bind to the calcium chloride . 9:1 ratio must be maintained.
Would short draws specimen be falsely prolong or falsely shorten?
Falsely prolong clotting times
What are transportation and storage requirements for specimens?
-Keep tube stoppered & in upright position to maintain proper pH
-Samples should not be chilled. transport to the lab at RT; chilling whole blood may activate: platelets, factor VII & VIIa, contact system.
Never refrigerate blood/plasma for ____; and test within ____ hours
PT; 24 hours
May refrigerate blood/plasma for ____; but need to test within ____hours. plus must spin and/or remove plasma __- hour if patient is on heparin.
APTT; 4 hours; 1 hour
Platelet Rich Plasma (PRP) is slow spin and used for _______.
Platelet aggregation studies.
Platelet Poor Plasma (PPP) is faster spin and used for ______
Used for all routine coagulation assays such as PT and APTT.
Do PT and APTT measure platelets?
Platelet Free Plasma (PFP) is faster spin, remove plasma, and re-spin and is used for ______
Heparin or heparin-induced antibody (HIT)
What does APTT stand for?
Activated partial Thromboplastin Time