Laboratory Evaluation Primary Hemostasis Flashcards
Serves to _____________ through the formation of a ___________.
- immediately limit bleeding
- platelet plug
Major product of Primary hemostasis:
Initially stop the bleeding;
Temporary platelet plug
Platelets play a key role in the ________ to blood vessel injury by:
o Adhering to the __________ at the site of injury
➢ ___ and _______ is responsible for the adhesion
o Releasing potent __________
o Aggregating to form a plug
o Providing a phospholipid surface for _______________
- rapid response
- endothelial wall
- vWF and GP-Ib
- anticoagulant compounds
- activated coagulation enzyme complexes
Are generally associated with mucocutaneous bleeding, characterized by:
o Epistaxis (nose bleeding)
o Ecchymosis (bruise)
o Genitourinary bleeding
o Gingival bleeding
A typical patient with defective primary hemostasis might experience _______________ and require the application of pressure for a prolonged period to stop the bleeding.
profuse bleeding from small cut
• Provides assessment of _______ and ______
o _________ for platelet function
o Assesses the _______ and _________
• Measures ____________.
- bleeding time
- platelet count and function
- Original test
- platelet and blood vessel wall
- platelet plug formation
focuses on the function
Qualitative
focuses on thrombocytopenia and thrombocytosis
Quantitative
FACTORS AFFECTING BLEEDING TIME
- Elasticity of the cut tissue
- Ability of the blood vessel to constrict and retract
- Mechanical and chemical action of platelets in the formation of hemostatic plug
- Intracapillary pressure
- Skin thickness at the puncture site
- Size and the depth of the wound
• This can be performed in ______ or ______.
• Normal Value: ______
- Duke’s Method
- earlobe or finger
- 1-3 minutes
• Best method to ________. It is considered to be the best screening test available for _________________.
- Best method to assess platelet plug
- Done in the volar surface of the forearm
• Normal Value: _______
• Standardized pressure: ________
- MODIFIED IVY’S METHOD
- assess platelets
- platelet’s role in hemostasis
- 3-6 minutes
- 40-60mmHg
• Involve immersion of the wound finger in a sterile NSS warmed at _____ until bleeding stops.
- This method is considerably ______ as it
involves pricking the finger and then submerging it in a sterile NSS solution.
- Not practically used in the laboratory
• Normal Value: _________
- COPLEY LALITCH METHOD
- 37°C
- more toxic
- 170-340 seconds
PROCEDURE FOR COPLEY LALITCH & ADELSONCROSBY METHOD
- Clean the finger
- Make a puncture wound 6mm deep
- Immerse the wound in sterile physiological saline warmed to 37°
- Leave it until there is no free flow of blood
- The BT is measured from the moment of the wound of the cessation of bleeding
• Assesses the _______________ on the Duke’s Bleeding Time.
- Duke’s bleeding time first → 2 tabs of Aspirin
will be taken by the px → They will run the test
again
• _____________ = Bleeding time via Duke’s method
- ASPIRIN TOLERANCE TEST
- effect of a standard dose of aspirin
- 2 Tablets of Aspirin (10mg)
• Normal Value: _________
- TEMPLATE METHOD
- 3-6 minutes
When platelets are greatly reduced
✓ Thrombocytopenic purpura
✓ Acute Leukemia
✓ Aplastic Anemia
Injury
✓ Scurvy (Vit. C Deficiency) –defective collagen synthesis
✓ Toxins – Infection, Chemical, Snake venom
Prothrombin deficiency
✓ Destructive disease of the liver
✓ HDN (Hemolytic Disease of Newborn)
CONDITION WITH PROLONGED BLEEDING TIME
- When platelets are greatly reduced
- Injury
- Prothrombin deficiency
- Slightly prolonged in severe anemia
PLATELET COUNT
- DIRECT METHOD
- Guy and Leake
- Rees and Ecker
- Brencher-Cronkite Method
- Electronic Method - INDIRECT METHOD
- Fonio’s Method
- Dameshek Method
• Platelets are counted in a _________ as in erythrocytes and leukocytes.
• Uses ___________, __________, and __________.
- Direct Method
- hemocytometer
- RBC thoma pipette, hemocytometer and diluting reagent
• Diluent is made of _________, _________ and __________.
• _________ – preserves the platelets
• _________ – a dye for identification
- GUY AND LEAKE
- sodium oxalate, 40% formalin and crystal violet
- 40% Formalin
- Crystal violet
Formula of Guy and Leake
Platelets/uL = platelets counted × 5 × 10 × 100
• 100 is the dilution
- If RBC, the aspirated blood is 1 mark and 101 is to make dilution 1:100
• Also known as _________
• Diluent is made up of _________, _________, _______ and _________.
• Counted in the _____________
• Low count
• Uses ________; Perform ________
- REES AND ECKER
- Tocantin’s Method
- sodium oxalate, brilliant cresyl blue, formalin and distilled water
- 25 RBC Squares
- WBC pipette
- 1:20 dilution
Formula of Rees and Ecker
Platelets counted × 10 × 200
Platelets / uL = 5
• But if it is Rees-ecker, the dilution is 200. The
blood is until 0.5 mark and then filled with DF until 101, in order to make 1:200 dilution.
• Best method
• Uses ______________
• Uses ____________ as the diluting fluid = ________
- BRENCHER-CRONKITE METHOD
- phase contrast microscopy
- 1% ammonium oxalate
- best diluting fluid
• Red cells must first be removed from whole blood, either by _______ or by _____________.
o Voltage-pulse counting
✓ Dilution: ________
✓ 3 uL of whole blood + 9 uL of NSS = 1:3000
o Electro-optical counting
✓ Dilution: _________
- ELECTRONIC METHOD
- sedimentation
- controlled centrifugation
- 1:3000
- 1000:15000
• Platelets are counted in their relationship to red cells on a ____________.
• This method is NOT RELIABLE because the results depend upon ____________ and on the ___________.
o Before counting, you need to ________________. Check all fields.
- INDIRECT METHOD
- fixed-stained smear
- the distribution of platelets and red cell count
- check the distribution of the cells
Fonio’s Method
14% MgSO4 + 1 drop of blood + Wright stain
• Brilliant Cresyl Blue, Sodium Citrate, sucrose and formalin; counter stain with Wright’s Stain.
o ____________ – used as a dye
o_____________ – prevent coagulation
o _____________ – preserve platelets
o ____________ – for counter-staining
- DAMESHEK METHOD
- Brilliant cresyl blue
- Sodium citrate
- Sucrose and Formalin
- Wright’s stain
Formula of DAMESHEK METHOD
Platelets counted × RBC count
Platelets / uL = 1000
TEST FOR ADHESION OF PLATELETS
- BORCHGREVINK METHOD
- SALZMAN METHOD
• Platelets are enumerated in the capillary blood oozing from a bleeding time puncture
o This test is _____________.
o Upon pricking the finger, the sample will be
collected immediately.
• Expressed as a __________ of the venous platelet count
-BORCHGREVINK METHOD
- significantly more toxic
- percentage
• Also known as _______________
• Test for the ____________ within glass bead columns
• ___________ is aspirated directly from the vein through a bead column and into a vacutainer.
o It could either be _____ or ______
• _______ of platelets are loss
• Uses 3 test tubes:
✓ 1ST TUBE – _______
✓ 2nd TUBE – ________
✓ 3rd TUBE – ____________________.
- SALZMAN METHOD
- Glass Bead Retention Test
- retention of platelets
- Venous blood
- EDTA or Heparin
- 75-95%
- Control
- Platelet count
- Platelet count. However, lower count
Formula of SALZMAN METHOD
2nd tube - 3rd tube
1st tube × 100
Employs the use of __________
various aggregometers
Agonists such as _________, ________, and _________
Epinephrine, Collagen and Viscositin
Measures the changes in optical density of a platelet suspension under conditions of ____________ and __________
constant temperature and continuous agitation
________ might change
Shape
Studied in suspensions of __________ (____)
citrated plasma (PRP)
Evaluation of ___________ and _____________.
suspected hereditary and acquired disorders of platelet function
Aggregation performed to ________ of the platelets.
identify the function
Defects of adhesion
Bernard Soulier Syndrome
Defects of aggregation
Glanzmann thrombasthenia
Defects of secretion
✓ Alpha or Dense Granule Deficiency
✓ Aspirin-like Defects
ACQUIRED PLATELET FUNCTION DISORDERS:
• Drug-induced platelet dysfunction (aspirin, clopidogrel, antibiotics)
• Uremia
• Myeloproliferative disorders
Thrombin
- 1 unit/mL
- PAR1 and PAR4; GP Iba and GP V
ADP
- 1–10 uM
- P2Y1, P2Y12
Epinephrine
- 2–10 mg/mL
- a2-adrenergic receptor
Collagen
- 5 mg/mL
- GP Ia/IIa, GP VI
Arachidonic acid
- 500 uM
- TPa, TPb
Ristocetin
- 1 mg/mL
- GP Ib/IX/V in association with von Willebrand
factor
induces activation
Thrombin
most common agonist
ADP
binds with platelets and alpha2-
adrenergic receptor (identical with muscle receptors)
o Does not work in Whole Blood Aggregometry
Epinephrine
a substrate for eicosanoid pathway
Arachidonic
VWD TYPE 1 AND 2A
- N
- N
- A/R + +
- A
- N
- N
VWD TYPE 2B
- N
- N
- N
- H
- N
- N
Bernard-Soulier Syndrome
- N
- N
- A
- A
- N
- N
Glanzmann thrombasthenia
- A
- A
- N
- A
- A
- A
Storage Pool Disease
- P/N
- R/N
- N
- A
- R
- R/N
Cyclooxygenase defect
- R/N
- R
- N
- A
- R
- R/N
• Depends on normal number of contractile platelets, the presence of calcium and ATP, and a normal concentration of fibrinogen.
• Involves ___________ – a contractile protein from platelets
• Abnormal CRT yields to:
o ________ = does not retract
o ____________________
o ____________ = proteins are coated with
platelets
- CLOT RETRACTION TIME
- thrombosthenin
- Low platelet
- Low concentration of Fibrinogen
- Para-proteneimia
CLOT RETRACTION TIME METHOD
- Hirshboek Method or Castor Oil Method
- Stefanini Method
- Macfarlane Method
• Uses tube that has ___________ and ____________ in the tube.
• Results are taken _________
• Measures the presence of ___________
o Nipple-like protrusion = _______
• A drop of blood in the tube must show protrusion or maple like protrusion = _________
- Hirshboek Method or Castor Oil Method
- 5-10 mL of castor oil and 20 uL of blooddropped
- within 15-45 minutes
- Dimpling Phenomenon
- Retraction
- platelets retracted
• Uses a ____ in the tube
• Checks clot or if sample is retracted. If the sample will be destructed when rolled over to a
___________.
• Measures ________
- Macfarlane Method
- wire
- gauze or tissue
- within 1 hour
MACFARLANE FORMULA
%serum = Volume of serum × Volume of WBC × 100
Reference Range: 44-67%
• Clot nonretractile or retracts poorly
• Clot edematous/friable
Platelet deficiency
a) Thrombocytopenia
b) Thrombasthenia
Blood does not clot
Afibrinogenemia
Clot is normal, increase red cell fall out
Fibrinogenopenia
• Defective retraction;
clot flabby/fragile
• Increased red cell fall out
o When the clot collected using coiled wire is
rolled over the gauze and it breaks, this means that it is not a good clot.
Increase in Blood Constituents
a) Thrombocythemia
b) Polycythemia
• Layered clot
• Clot may not retract or may retract poorly
• Rapid sedimentation of red cell
o Non-functional because it is covered with protein.
Hyperproteinemia
a) Multiple myeloma
b) Waldenstrom Macroglobulinemia
• Test for the stability of the small blood vessels to retain the red cell in their lumen under conditions of stress and trauma
- CAPILLARY FRAGILITY OR CAPILLARY RESISTANCE TEST
• Positive pressure technique
• By partially obstructing the venous blood, the capillary pressure is increased and will give rise to ______________.
• Which will be manifested in the form of small
hemorrhage called ________.
o Petechia – _______
o Example 100 mmHg pressured use = petechiae = _________________________
• __________ of blood pressure; not immediately read
- TORNIQUET OR RUMPEL – LEEDE OR HESS TEST
- intravasation of blood
- petechiae
- red spot
- the blood vessels cannot with stand and blood leaks out
- 5 minutes
Few petechiae on the anterior part of forearm
- 1+
- 0-10
Many petechiae on the anterior part of forearm
- 2+
- 10-20
Multiple petechiae over the anterior and the back of the hand
- 3+
- 20-50
Confluent petechiae over the anterior and the back of the hand
- 4+
- > 50
• Negative pressure method
• Employs the use of a modified ___________
• The cup is applied to the surface of the arm for a period of ________ at 200 mmHg
• The resistance of the capillaries is expressed as the least negative pressure required to produced macroscopic petechiae
• Measures how the blood vessels hold the pressure applied = if not, petechiae will show.
• Normal Value: ____________
- SUCTION CUP OR PETECHIOMETER METHOD
- da Silva Melle instrument
- one minute
- Less than 4 petechiae
INDICATIONS OF INCREASE CAPILLARY RESISTANCE TEST
✓ Thrombocytopenia
✓ Thrombocythemia
✓ Vascular purpura
✓ Scurvy – Vitamin C deficiency
✓ Senile purpura – usually seen in old patients; more prone in male
