(M) Lesson 6: Platelet Count and Function Test (Part 2)

Question 1

• One of the most traditional tests used in the 1900s
• Ordered by physicians prior to surgery
• Useful to assess bleeding tendency of patient
• When a patient is subjected to certain procedures, some patients have prolonged results

Answer 1

Bleeding Time

Question 2

• The interval required for the blood to stop flowing from a skin lesion
• Assesses the primary hemostasis

Answer 2

Bleeding Time

Question 3

To determine the bleeding time, we need what type of incision?

Answer 3

Skin incision

Question 4

Measures the ability of platelets to adhere to the endothelium

Answer 4

Bleeding Time

Question 5

What is the primary purpose of bleeding time tests?

Answer 5

Measures/assesses primary hemostasis

Question 6

Match the following.

1. Primary Hemostasis
2. Secondary Hemostasis

A. Platelet and Blood Vessels
B. Coagulation Factors/Clotting Factors

Answer 6

1. A
2. B

Question 7

What are the different materials needed in assessing bleeding time?

Answer 7

1. Lancet
2. Filter Paper
3. Cotton Balls
4. 70% Alcohol
5. Stopwatch
6. Sphygmomanometer

Question 8

Match the following.

1. Preferred over the ordinary type because it can make a better incision and guarantee more sufficient volume of blood collected
2. Skin incision
3. Blot the drop of blood
4. Used as antiseptic
5. Records the time
6. Used in Ivy’s Method

A. Lancet
B. Sphygmomanometer
C. Filter Paper
D. Cotton Balls
E. 70% Alcohol
F. Stopwatch

Answer 8

1. A
2. A
3. C
4. E
5. F
6. B

Question 9

Duke’s Method

1. Select the punctured area and disinfect the site with ____
2. Without applying pressure on the puncture site, make a firm quick stab to produce a standard ____ deep wound.
3. When the blood shows from the punctured site, start timing it using a ____. Do no touch the wound.
4. Wait for ____ to lapse and blot the blood coming out of the puncture site with a ____, without allowing the paper to come into contact with the ____.
5. Blot the drop every ____. Endpoint is reached when ____.
6. Record the time when no more blood appears.

Answer 9

1. Select the punctured area and disinfect the site with 70% alcohol.
2. Without applying pressure on the puncture site, make a firm quick stab to produce a standard 3mm deep wound.
3. When the blood shows from the punctured site, start timing it using a stopwatch. Do no touch the wound.
4. Wait for 30 seconds to lapse and blot the blood coming out of the puncture site with a filter paper, without allowing the paper to come into contact with the skin.
5. Blot the drop every 30 seconds. Endpoint is reached when no more blood is absorbed by the filter paper.
6. Record the time when no more blood appears.

Question 10

Duke’s Method

Normal bleeding time?

Answer 10

2 to 4 minutes

Some labs say 1 to 3 minutes, it is dependent on the policies.

Question 11

Duke’s Method

1. Squeezing the finger
2. Less than 2 to 3 mm depth puncture
3. More than 2 to 3 mm depth puncture
4. Filter paper touching skin while blotting

A. Falsely prolonged
B. Falsely shortened

Answer 11

1. B
2. B
3. A
4. B

Question 12

Duke’s Method

Prolonged bleeding time is seen in what four (4) phenomena?

Answer 12

1. When the blood platelets are greatly reduced
2. In injury to capillary wall
3. In prothrombin deficiency
4. Slightly prolonged severe anemia

Question 13

Duke’s Method

What are the three (3) diseases/disorders wherein we observe prolonged bleeding time?

Answer 13

1. Thrombocytopenia purpura
2. Acute Leukemia
3. Aplastic Anemia

Question 14

Duke’s Method

• Bone marrow failure
• Associated with pancytopenia (all types of cell lineage are refuced)

Answer 14

Aplastic Anemia

Question 15

Duke’s Method

What are three (3) injuries to the capillary wall?

Answer 15

1. Scurvy
2. Toxins
3. Allergy

Question 16

Which two (2) phenomena can we observe prothrombin deficiency?

Answer 16

1. Destructive disease of the liver of the liver with hemorrhagic tendencies
2. Hemolytic disease of the newborn

Question 17

T or F: Bleeding Time test is obsolete internationally.

Answer 17

T

Question 18

What are the three (3) reasons why bleeding time test lack clinical benefit?

Answer 18

1. In the absence of a history of a bleeding disorder, the bleeding time is not a useful predictor of the risk of hemorrhage associated with surgical procedures
2. A normal bleeding time does not exclude the possibility of excessive hemorrhage associated with invasive procedure
3. The bleeding time cannot be used to reliably identify patients who have recently ingested aspirin or NSAIDs or those who have a platelet defect attributable to those drugs.

Question 19

• Modification of Duke’s Method (wherein there is increased capillary pressure)
• Provides a very accurate technique if the incisions are identical

Answer 19

Ivy’s Method

Question 20

Standard pressure of Ivy’s Method

Answer 20

40 mmHg

Question 21

Ivy’s Method (Part 1)

1.Apply blood pressure cuff on one arm of the patient and inflate to ____, which is to be maintain throughout the test.
2.Let arm to rest on a flat comfortable surface that is well lighted.
3.Choose an area of the ventral part of the arm, preferably near the ____, that does not have visible blood vessels.
4.Disinfect area with ____ and allow spontaneous drying.
5.Make a standard ____ wound with a lancet without hitting any visible blood vessels in the vicinity of the chosen site.

Answer 21

1.Apply blood pressure cuff on one arm of the patient and inflate to 40mm Hg pressure, which is to be maintain throughout the test.
2.Let arm to rest on a flat comfortable surface that is well lighted.
3.Choose an area of the ventral part of the arm, preferably near the antecubital area, that does not have visible blood vessels.
4.Disinfect area with 70% alcohol and allow spontaneous drying.
5.Make a standard 3mm wound with a lancet without hitting any visible blood vessels in the vicinity of the chosen site.

Question 22

Ivy’s Method (Part 2)

6. Start timing when ____
7. After ____, blot blood with filter paper.
8. Repeat blotting ____ time interval.
9. Record time at the point where no more blood adheres on the filter paper (end point).
10. Remove pressure cuff and place dry cotton on the puncture site for few minutes.
11. Each blot in the filter paper represents ____.
12. Report bleeding time as to minutes and seconds the test was completed.

Answer 22

6. Start timing when blood appears on the puncture site.
7. After 30 seconds, blot blood with filter paper.
8. Repeat blotting every 30 seconds time interval.
9. Record time at the point where no more blood adheres on the filter paper (end point).
10. Remove pressure cuff and place dry cotton on the puncture site for few minutes.
11. Each blot in the filter paper represents 30 seconds.
12. Report bleeding time as to minutes and seconds the test was completed

Question 23

• Test to determine the ability of platelets to adhere to glass surfaces

Answer 23

Platelet Adhesiveness/Retention Test

Question 24

Platelet Adhesiveness/Retention Test

____ is passed through a glass bead column.

Answer 24

Whole blood

Question 25

# Platelet Adhesiveness/Retention Test Platelet count obtained in glass beads is ____ than obtained by venipuncture.

Answer 25

Lower

Question 26

# Platelet Adhesiveness/Retention Test Normal value?

Answer 26

26-60%

Question 27

# Platelet Adhesiveness/Retention Test 1. Glanzmann's thrombasthenia 2. von Willebrand disease 3. Chediak-Higashi Syndrome 4. Uremia 5. Aspirin Ingestions **Increased or decreased levels of platelet adhesiveness?**

Answer 27

Decreased

Question 28

# Platelet Adhesiveness/Retention Test 1. Venous thrombosis 2. Pulmonary embolism 3. Carcinoma 4. Pregnancy 5. Splenectomy 6. Patients taking oral contraceptives **Increased or decreased levels of platelet adhesiveness?**

Answer 28

Increased

Question 29

* Involves serial platelet counts on blood exuding from a forearm incision * Platelet counts **decrease** because of platelet adhesion to wound * Results are compared with a venous blood platelet count

Answer 29

Platelet adhesiveness in vivo

Question 30

# Platelet adhesiveness in vivo Normal value?

Answer 30

15 to 45%

Question 31

What is the clinical significance of CRT?

Answer 31

To assess platelet function

Question 32

CRT is affected by which four (4) factors?

Answer 32

1. Clotting Factor Deficiency 2. Severe decrease on Platelet count 3. Heparin and other anticoagulant treatment 4. Asprin and NSAIDs administration

Question 33

What are the three (3) methods of clot retraction?

Answer 33

1. McFarlane method 2. Hirschboeck method 3. Stefanini method

Question 34

Please study the procedures of these na lang, I don't think they'll ask too much.

Answer 34

Thank you so much mwa. Bow.

Question 35

* Stimulated by activators such as **kaolin** and **epinephrine.**

Answer 35

Platelet Factor 3 Assay

Question 36

Anticoagulant of choice for PF3?

Answer 36

3.2% Sodium Citrate

Question 37

What are the four (4) different reagents for PF3?

Answer 37

1. 0.025 M CaCl2 2. Kaolin 3. Epinephrine (109 uM) 4. Commercially available normal control plasma or pooled PPP

Question 38

Please study the procedures for PF3.

Answer 38

Di ko na kaya itype yon hehe labyu sorry mwa.

Question 39

* A metabollic process wherein binding of any of the agonists to their respective membrane receptors initiates signaling pathways that ultimately convert GpIIb-IIIa

Answer 39

Platelet Aggregation

Question 40

Upon platelet-to-platelet interaction, platelets change shape from what to what?

Answer 40

Biconvex to sphere (morphological change)

Question 41

# Platelet Aggregation What are the reagents and equipment for the test for platelet aggregation?

Answer 41

1. Platelet Aggregation Reagents 2. Cuvettes 3. Plastic pipettes 4. Plastic test tubes 5. Magnetic stir rods

Question 42

# Platelet Aggregation What are the six (6) platelet aggregation reagents?

Answer 42

1. ADP/ATP 2. Epinephrine 3. Collagen 4. Arachidonic acid and ristocetin 5. Thrombin/Thromboxane A2

Question 43

# Platelet Aggregation Uses a special type of photometer to detect the percent transmittance that is being recorded during testing

Answer 43

Aggregometry

Question 44

# Platelet Aggregation Stirs the plasma with the reagents

Answer 44

Magnetic stir rods

Question 45

# Platelet Aggregation What are the two (2) special patient requirements?

Answer 45

1.Patient and normal control should be fasting *(8 to 10 hours to avoid lipemic samples)* 2.Patients should not be taking aspirin or NSAIDs

Question 46

# Platelet Aggregation All specimens must be drawn using a ____ syringe.

Answer 46

Plastic

Question 47

# Platelet Aggregation ____ is the specimen of choice.

Answer 47

Platelet-rich plasma | You need to observe the **aggregation.**

Question 48

# Platelet Aggregation Specimen should be stored at ____.

Answer 48

Room temperature

Question 49

# Match the basic requirements to the reason. 1. Hemolyzed samples releases ADP which can prematurely activates platelets 2. The calcium content with sodium citrate is still sufficient for aggregation to occur. 3. To maintain an optimal activity of the platelet. 4. Cooling inhibits the platelet aggregating response. Just before performing the test the plasma is incubated at 37 deg C at the heat block of aggregometer. 5. Lipemic plasma may obscure changes in optical density during platelet aggregation. 6. In able for aggregation to occur. A. No hemolyzed sample B. Plasma from fasting patient is preferred for testing C. Sodium citrate is the anticoagulant used in aggregation studies. D. Fibrinogen must be present in the plasma. E. Aggregated studies should be performed at 37 deg C at a pH of 6.5 to 8.5. F. Test samples should be maintained at room temp during processing.

Answer 49

1. A 2. C 3. E 4. F 5. B 6. D

Question 50

# Match the basic requirements to the reason. 1. The drugs inhibit the platelet release reaction that induces platelet aggregation 2. To prevent lost of platelet activity. 3. To allow the platelet regain their responsiveness after the preparation procedure 4. To maintain the potency of the aggregating reagents. A. PRP should be allowed to stand for 30 minutes prior to aggregation test. B. All aggregation studies should be done within 3 hours of sample collection. C. Aggregating agents should be prepared fresh daily and brought to room temperature D. Patient should be refrained from taking any antiinflammatory drugs at least 1 week prior to testing

Answer 50

1. D 2. B 3. C 4. A

Question 51

# Principle of Platelet Aggregation Test ____ is placed in the test wall of the platelet aggregometer before the aggregating reagent is added.

Answer 51

Platelet rich plasma

Question 52

# Principle of Platelet Aggregation Test ____ is monitored.

Answer 52

Optical density

Question 53

# Principle of Platelet Aggregation Test When substance that promotes platelet activation and aggregation (agonist) is added to PRP, normal platelets are ____ and ____.

Answer 53

Activated and aggregate.

Question 54

# Principle of Platelet Aggregation Test Is considered gold standard for platelet function testing.

Answer 54

Light Transmission Platelet Aggregometry (LTA)

Question 55

Study the procedure for platelet aggregometry.

Answer 55

Please ayoko na.

Question 56

# Interpretation of Results for Platelet Aggregation Test This measures change in optical density (or light transmittance) of stirred PRP that occurs after addition of agonists.

Answer 56

LTA

Question 57

# Interpretation of Results for Platelet Aggregation Test Presents change in light transmission (y-axis) against time in minutes (x-axis)

Answer 57

Aggregation Tracing

Question 58

# Interpretation of Results for Platelet Aggregation Test What are seven (7) parameters to be evaluated?

Answer 58

1. Lag phase 2. Platelet shape change 3. Primary aggregation slope 4. Secondary aggregation 5. Disaggregation 6. Maximum amplitude 7. Percent aggregation

Question 59

# Platelet Aggregation von Willebrand disease and Bernard-Soulier disease affects which agonist?

Answer 59

Ristocetin

Question 60

# Notes on Platelet Aggregation T or F: We should refrigerate the samples for platelet aggregation.

Answer 60

False

Question 61

# Match the following agonists to their pH. 1. ADP 2. Epinephrine 3. Ristocetin 4. Collagen A. Between 7.7 to 8.0 B. 7.3 but not above 7.7 C. 7.0 to 8.0

Answer 61

1. A 2. A 3. B 4. C

Question 62

Used to quantitate antigens other than immunoglobulins.

Answer 62

Rocket immunoelectrophoresis (Laurell) for detecting vWF Ag

Question 63

# vWF Ag 1. The ____ is incorporated into the agar, and the known antigen is placed in the well and electrophoresed. 2. The antigen migrates through the gel, it combines with ____, and forms precipitate forming lateral boundaries in shape of ____ 3. The distance of antigen migration and precipitation is ____ proportional to the antigen concentration.

Answer 63

1. The **antiserum** is incorporated into the agar, and the known antigen is placed in the well and electrophoresed. 2. The antigen migrates through the gel, it combines with **antibody**, and forms precipitate forming lateral boundaries in shape of **rocket**. 3. The distance of antigen migration and precipitation is **directly** proportional to the antigen concentration,.

Question 64

Study the procedures for Rocket immunoelectrophoresis (Laurell) for detecting vWF Ag.

Answer 64

Kaya niyo na yan mwa.

Question 65

Also known as the tourniquet test.

Answer 65

Rumple-Leed Test/Capillary Fragility Test

Question 66

Study the procedures for the Ruple-Leede Test.

Answer 66

Last na yan mwa.

Question 67

# Match the following. 1. 51+ petechia 2. 11-20 petechia 3. 21-50 petechia 4. 0 to 10 petechia A. +1 B. +2 C. +3 D. +4

Answer 67

1. D 2. B 3. C 4. A