1. DIRECT METHOD - Guy and Leake - Rees and Ecker - Brencher-Cronkite Method - Electronic Method 2. INDIRECT METHOD - Fonio's Method - Dameshek Method

Laboratory Evaluation Primary Hemostasis Flashcards by Queenie Mae

Serves to _____________ through the formation of a ___________.

immediately limit bleeding
platelet plug

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Major product of Primary hemostasis:

Initially stop the bleeding;
Temporary platelet plug

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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

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Are generally associated with mucocutaneous bleeding, characterized by:

o Epistaxis (nose bleeding)
o Ecchymosis (bruise)
o Genitourinary bleeding
o Gingival bleeding

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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

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• 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

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focuses on the function

Qualitative

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focuses on thrombocytopenia and thrombocytosis

Quantitative

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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

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• This can be performed in ______ or ______.
• Normal Value: ______

Duke’s Method
earlobe or finger
1-3 minutes

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• 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

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• 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

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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

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• 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)

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• Normal Value: _________

TEMPLATE METHOD
3-6 minutes

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When platelets are greatly reduced

✓ Thrombocytopenic purpura
✓ Acute Leukemia
✓ Aplastic Anemia

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Injury

✓ Scurvy (Vit. C Deficiency) –defective collagen synthesis
✓ Toxins – Infection, Chemical, Snake venom

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Prothrombin deficiency

✓ Destructive disease of the liver
✓ HDN (Hemolytic Disease of Newborn)

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CONDITION WITH PROLONGED BLEEDING TIME

When platelets are greatly reduced
Injury
Prothrombin deficiency
Slightly prolonged in severe anemia

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PLATELET COUNT

DIRECT METHOD
- Guy and Leake
- Rees and Ecker
- Brencher-Cronkite Method
- Electronic Method
INDIRECT METHOD
- Fonio’s Method
- Dameshek Method

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• Platelets are counted in a _________ as in erythrocytes and leukocytes.
• Uses ___________, __________, and __________.

Direct Method
hemocytometer
RBC thoma pipette, hemocytometer and diluting reagent

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• 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

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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

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• 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

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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

Laboratory Evaluation Primary Hemostasis Flashcards

(80 cards)