SPECIMEN COLLECTION AND PROCESSING FOR HEMOSTASIS

Question 1

SPECIMEN COLLECTION AND PROCESSING FOR HEMOSTASIS
General Considerations - Primary concern is to…

Answer 1

prevent premature activation of the clotting process

Question 2

Contamination with_____
Activates clotting early

Answer 2

tissue thromboplastin

Question 3

PROPER container:

Answer 3

Sodium Citrate (Light Blue Top)

Question 4

Improper temperature

Labile Coagulation Factors at Room Temperature (20–24°C):

Answer 4

• Factor V (Labile Factor)
• Factor VIII (Anti-hemophilic Factor)

Question 5

Coagulation Factors Prematurely Activated at Refrigerated Temperature (below 20°C):

Answer 5

• Factor VII (Proconvertin)
• Factor XI (Plasma Thromboplastin Antecedent)

Question 6

Causes of Hemolysis

Answer 6

• Prolonged tourniquet application (< 1 min.)
• Moisture or contamination
• Using needles with too small bore
• Frothing of sample due to air entry
• Expelling of blood from the syringes through the needle
• Excessive and vigorous mixing

Question 7

GENERAL CONSIDERATIONS
- primary concern is to prevent premature activation of the clotting process.

Answer 7

1. Contamination with Tissue thromboplastin
2. Inappropriate container
3. Improper Temperature
4. Hemolysis

Question 8

Needle Size - needles with _____are more likely to cause hemolysis

______- most commonly used for coagulation samples

______- collection of more than 20 mL of blood

______- narrow or small veins

Answer 8

small bores

20-gauge needle

19-gauge needle

21-gauge needles

Question 9

Evacuated Tubes/ Syringes - should be______ coated

Answer 9

silicone

Question 10

Evacuated tubes or syringes are silicone-coated to……

Answer 10

prevent platelet activation and clot formation during blood collection.

Question 11

Forms insoluble complexes or precipitates once recalcified and produces an interference in OD testing

Answer 11

Potassium Chloride

Question 12

Binds to calcium

Answer 12

Trisodium Citrate

Question 13

Trisodium Citrate ratio

Answer 13

9:1

Question 14

Trisodium Citrate

Concentration:
_________ - (preferred)
_________- over anticoagulation for patients with high hematocrit

Answer 14

3.2% Na Citrate

3.8% Na Citrate

Question 15

Anticoagulant

Unsuitable for coagulation
Inhibits fibrinogen - thrombin reaction
• Factor V is suitable in its presence

Answer 15

EDTA (Ethylenediamine tetraacetic acid)

Question 16

Factor______remains stable in the presence of EDTA, but since other steps are blocked, coagulation tests are still unreliable.

Answer 16

Factor V

Question 17

• Acts with antithrombin Ill and inhibits all stages of coagulation

Can be used for platelet retention test

Answer 17

Heparin

Question 18

Blood Collection
In performing venipuncture for coagulation testing, contamination of_______ and_____ is prevented.

• In the event of difficulty in blood collection, the attempt should be discontinued, then….

Answer 18

tissue factor and air

a new site must be chosen, and new blood collection equipment must be prepared for use.

Question 19

Excessive redirection could lead to ______ and could cause the platelets to______ causing interference in tests

Answer 19

tissue damage

aggregate

Question 20

• For______ and_______, the vacuum tube method is acceptable if tissue juice contamination must be avoided.

In anticipation of difficulties while doing venipuncture or if blood is being drawn for special procedures, using______ method is recommended

Answer 20

Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT)

TWO-SYRINGE method

Question 21

Specimen Handling and Processing

EFFECTS OF pH
• Changes in pH can prolong clotting times
• Mediated by loss of CO2
• Samples should be_____ if immediate testing is not possible

TEMPERATURE
• Labile factor
• Prematurely activated @___deg C

CENTRIFUGATION
•____g for ___mins to obtain platelet poor plasma
• Only _____of plasma layer should be used for testing

Answer 21

unopened

4C

2000g for 10 mins

upper ¾

Question 22

TEST FOR PRIMARY HEMOSTASIS
Involves:

Answer 22

PLATELET COUNT & FUNCTION and BLOOD VESSEL WALL

1. Bleeding Time
2. Capillary Resistance Test (Fragility Test)
3. Clot Retraction Time
4. Platelet count
5. Platelet aggregation
6. Platelet adhesiveness

Question 23

Primary hemostasis

Answer 23

The initial response to blood vessel injury, where platelets aggregate and adhere to the exposed collagen at the injury site.

Question 24

Primary hemostasis

Key Steps:

Answer 24

1. Vasoconstriction: Blood vessels narrow to reduce blood flow.
2. Platelet Adhesion: Platelets stick to the exposed collagen via von Willebrand factor (vWF).
3. Platelet Activation: Platelets change shape and release substances to recruit more platelets.
4. Platelet Aggregation: Platelets clump together, forming a temporary “platelet plug.”

Question 25

Platelets INACTIVATED FORM of PLT: ACTIVATED FORM of PLT:

Answer 25

Round; Discoid shape Pseudopodia

Question 26

Secondary hemostasis

Answer 26

This is the process that stabilizes and strengthens the initial platelet plug formed during primary hemostasis through the formation of a fibrin mesh.

Question 27

Coagulation Factors Involved: 1. Intrinsic Pathway: Activated by damage to the blood vessel surface. • Factors: 2. Extrinsic Pathway: Activated by external trauma that exposes tissue factor (TF). • Factors: 3. Common Pathway: Both pathways converge to form a strong clot. • Factors:

Answer 27

XII, XI, IX, VIII VII X, V, II (Prothrombin), I (Fibrinogen), XIII

Question 28

Secondary hemostasis End Result: • Formation of ______that weave through the platelet plug, making it stable and more resistant to breaking. • This solid clot helps to prevent further bleeding and promotes healing.

Answer 28

fibrin strands

Question 29

The actual time it takes for a standard wound to stop bleeding ; Obsolete tests

Answer 29

Bleeding Time

Question 30

DETECTS: Abnormalities of platelet number and function Factor VIII; vWF deficiency Abnormalities of vessel wall structure

Answer 30

Bleeding Time

Question 31

Bleeding time METHODS (2)

Answer 31

Modified Duke Method Ivy Method

Question 32

Bleeding time Modified Duke Method • Site:_____ • Tool:_____ • Procedure: • The blade punctures the earlobe and strikes a glass slide, producing a clicking sound. • Blood flow is monitored, and the time it takes to stop bleeding is recorded. • Normal Value (NV):_____

Answer 32

15–20 mm rounded fatty portion of the earlobe No. 11 sterile Bard-Parker Surgical Blade < 8 minutes

Question 33

Bleeding time Ivy Method • Site:______ • Pressure: _____applied using a blood pressure cuff to maintain consistent pressure. • Procedure: • _____punctures are made on the forearm. • ______is used to blot the blood after______, then every_____ until bleeding stops.

Answer 33

Volar surface of the forearm 40 mmHg Two Filter paper 2 minutes 30 seconds

Question 34

Detects abnormality of the capillaries due to a structural weakness in the capillary walls or thrombocytopenia; Abnormal in______ May be abnormal in (3)

Answer 34

Capillary Resistance Test (Fragility Test) hereditary telangiectasia hemophilia, Factor VII deficiency, and Vitamin K deficiency.

Question 35

Capillary Resistance Test (Fragility Test) 2 METHODS

Answer 35

Positive pressure test/ Rumpel-Leede/ Tourniquet test Negative pressure test

Question 36

Capillary Resistance Test (Fragility Test) Positive Pressure Test (Rumpel-Leede or Tourniquet Test) • Procedure: 1. Apply a _____to the upper arm. 2. Inflate to ____ (____for females). 3. Maintain the pressure for____ 4. Remove the cuff and observe for_____. Interpretation: • Normal:

Answer 36

blood pressure cuff 100 mmHg (80 mmHg) 5 minutes petechiae (small red or purple spots) formation Minimal or no petechiae.

Question 37

Capillary Resistance Test (Fragility Test) Negative Pressure Test • Procedure: 1. A______ (____ in diameter) is applied to the midportion of the upper arm. 2. Apply a pressure of 200–250 torr for_____min/s. 3. Wait for_____, then count the petechiae. • Interpretation: • Normal:______

Answer 37

suction cup (2 cm) 200-250 torr for 1 minute 5 minutes Few or no petechiae.

Question 38

Test for the time of the dissolution of the clot

Answer 38

Clot retraction time

Question 39

Clot Retraction Time METHOD

Answer 39

McFarlane Clot Retraction Technique

Question 40

Procedure (McFarlane Clot Retraction Technique): 1. Collect_____ of whole blood. 2. Incubate at____ for ____. 3. Observe as the clot shrinks and retracts from the tube walls. 4. The serum volume released from the clot is measured. Normal Values (NV): •_____ to _____ retraction is considered normal.

Answer 40

5 mL 37°C for 1 hour 44% to 67%

Question 41

Formula for Clot Retraction Percentage (% CRT):

Answer 41

% CRT = (Volume of Serum/Total Volume of Whole Blood) x 100

Question 42

Factors Affecting Clot Retraction: (3)

Answer 42

a. Number of contractible platelets b. Presence of calcium and ATP c. Normal concentration of fibrinogen

Question 43

Platelet count DIRECT METHODS (3)

Answer 43

Tonkantin Method Brecker-Cronkite Method Unopette Method

Question 44

Platelet count REFERENCE METHOD

Answer 44

Brecker-Cronkite Method

Question 45

Diluent used Tonkantin Method Brecker-Cronkite Method Unopette Method

Answer 45

Rees-Ecker Diluting Fluid 1% Ammonium Oxalate Tripotassium EDTA + Ammonium Oxalate

Question 46

Rees-Ecker Diluting Fluid (3) components

Answer 46

Na Citrate Formalin Brilliant Cresyl Blue

Question 47

Platelet count PRINCIPLE: Hemolysis of red cells by hypotonicity and complete block of platelet activity by chelating Mg and Ca with EDTA and ammonium oxalate

Answer 47

Unopette Method

Question 48

Platelet Aggregation Test Principle: • ______is mixed with aggregation agents. • These agents activate platelets, causing them to change ***shape and clump together (aggregate).*** • As aggregation occurs, the plasma becomes_____, allowing more light to pass through. • An_____ measures the increase in light transmission, indicating the degree of aggregation.

Answer 48

Platelet-Rich Plasma (PRP) clearer aggregometer

Question 49

Platelet Aggregation Test AGGREGATION AGENTS:

Answer 49

Epinephrine Collagen ADP Ristocetin

Question 50

Platelet Adhesiveness Test Principle: • The ______is used to assess platelet adhesiveness — the ability of platelets to stick to surfaces during blood flow. • When blood is passed through a glass bead column, platelets with normal_____ adhere and aggregate to the glass surface, mimicking how they attach to damaged blood vessels.

Answer 50

Glass Bead Test von Willebrand factor (vWF)

Question 51

measures the ability of platelets to stick to surfaces (like blood vessel walls or glass beads).

Answer 51

Platelet adhesiveness

Question 52

Platelet Adhesiveness Test PROCEDURE: 1. 1st sample is collected using____ tube 2. 2nd sample is collected using a____

Answer 52

EDTA tube glass bead collecting system

Question 53

Platelet Adhesiveness Test FORMULA: NV:

Answer 53

PA=(PC1-PC2/PC1) X 100 70% or greater