(M) Lesson 5: Platelet Count and Function Test (Part 1) Flashcards

1
Q

Platelet counts are important in helping diagnosing what type of disorders?

A

Bleeding

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2
Q

Relative platelet count provides what in the peripheral blood?

A

Estimate number of platelets

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3
Q

Platelets are counted under what objective?

A

OIO

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4
Q

What is the normal value of platelets?

A

150,000 to 400,000

Some books say 450,000

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5
Q

How many fields should be counted for platelets under OIO?

A

10 fields

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6
Q

T or F: Platelets are the same regardless of age group.

A

False

In newborns, platelets are higher/elevated.

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7
Q

How do we differentiate platelets from debris?

Clue: The unique characteristic of platelets.

A

Platelets are granulated.

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8
Q

When there is a deficiency of dense granules, platelets appear as?

A

Pale or gray

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9
Q

Four (4) reagents/equipment needed for platelet count

A
  1. Glass slides
  2. Wright Stain
  3. Microscope
  4. EDTA (Blood sample)
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10
Q

Reagents and Equipment

What are the two (2) methods that may be used in staining?

A
  1. Quick Staining Method (Dipping)
  2. Rack Method (Flooding)
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11
Q

Reagents and Equipment

T or F: Capillary blood may be used for platelet count in place of venous blood.

A

T

However, it is not preferred since it has interstitial fluid and must also be free-flowing.

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12
Q

What are the two (2) types of specimen that may be used for platelet count?

A
  1. Whole Blood (venous)
  2. Blood from heel or fingertip (capillary)

When using capillary blood, you have to wipe away the first drop of blood.

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13
Q

Platelet aggregation may be caused by what?

A

Traumatic venipuncture

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14
Q

Platelet aggregation caused by traumatic venipuncture causes (falsely decreased/falsely increased) platelet count.

A

Falsely decreased

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15
Q

Falsely decreased platelet count may be indicative of what two (2) phenomena?

A
  1. Pseudothrombopenia
  2. Pseudoleukocytosis
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16
Q

This phenomena happens when EDTA is used in place of citrate in platelet count procedures.

Clue: causes platelets to bind with WBCs (e.g. neutrophils)

A

Platelet satellitosis

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17
Q

Platelet satellitosis may also be caused by non-immunologic factors such as?

Two answers.

A
  1. Thrombospondin
  2. Alpha Granule Proteins
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18
Q

What is the remedy for difficulties such as platelet aggregation and platelet sattelitosis?

A
  1. Redraw with citrate
  2. Perform manual count
  3. Multiply by 1.1
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19
Q

FIll in the blanks.

  1. Prepare a ____ and stain it with routine hematological stain.
  2. Place the prepared slides under the microscope and focus the ____ portion of the smear using the ____ objective.
  3. Using the ____ method on moving the slide while focused, observe ____ fields and count the total number of platelets seen.
  4. Get the average platelet per field by dividing the ____ of platelets counted with 10.
  5. Calculate the relative platelet count using the formula (____)
A
  1. Prepare a blood smear and stain it with routine hematological stain.
  2. Place the prepared slides under the microscope and focus the thin portion of the smear using the oil immersion objective.
  3. Using the battlement method on moving the slide while focused, observe 10 fields and count the total number of platelets seen.
  4. Get the average platelet per field by dividing the total number of platelets counted with 10.
  5. Calculate the relative platelet count using the formula (Relative Platelet Count = Average platelet per field x 20,000)
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20
Q

What are the three (3) different methods in observing fields under the microscope?

A
  1. Battlement Method
  2. Longitudinal Method (Head to Tail)
  3. Cross-Sectional Method (Edges)
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21
Q

Which part of the blood smear do we count on?

A

Monolayer

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22
Q

Match the following.

  1. 0 to 49,000/uL
  2. 50,000 to 99,000/uL
  3. 100,000 to 149,000/uL
  4. 150,000 to 199,000/uL
  5. 200,000 to 400,000/uL
  6. 401,000 to 599,000/uL
  7. 600,000 to 800,000/uL
  8. Above 800,000/uL

A. Normal
B. Slightly Decreased
C. Moderately Decreased
D. Low Normal
E. Moderately Increased
F. Slightly Increased
G. Marked Increase
H. Marked Decrease

A
  1. H
  2. C
  3. B
  4. D
  5. A
  6. F
  7. E
  8. G
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23
Q

Match the following.

  1. 3 to 10 platelets
  2. 8 to 20 platelets

A. Per 100 RBC observed
B. Per 150 RBC observed
C. Per 200 RBC observed

A
  1. A
  2. C
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24
Q

What is the manner of reporting for semi-quantitative platelet estimate?

A

Increase, adequate, or decrease

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25
Q

What are the two (2) methods in manual absolute platelet counting?

A
  1. Rees and Ecker Method
  2. Unopette System
26
Q

Unopette or Rees and Ecker

Blood Used: EDTA anticoagulated blood

27
Q

Unopette or Rees and Ecker

  • Diluting Fluid Used: Brilliant Cresyl Blue + Formalin + Distilled H2O + Citrate
A

Rees and Ecker

Note: Those are components of the Rees and Ecker diluting fluid.

28
Q

Unopette or Rees and Ecker

  • Diluting Fluid Used: Ammonium Oxalate
A

Unopette System

29
Q

Unopette or Rees and Ecker

  • Pipette Used: Either WBC or RBC pipette
A

Rees and Ecker

30
Q

Unopette or Rees and Ecker

  • Pipette Used: Unopette System

Teh, ewan ko na lang talaga pag nagkamali ka.

A

Unopette System

31
Q

Unopette or Rees and Ecker

  • Dilution Made: 1:100, 1:20, 1:200
A

Rees and Ecker

32
Q

Unopette or Rees and Ecker

  • Dilution Made: 1:100
A

Unopette System

33
Q

Unopette or Rees and Ecker

  • Square Used: Either WBC or RBC squares
A

Rees and Ecker

34
Q

Unopette or Rees and Ecker

  • Square Used: RBC square
A

Unopette System

35
Q

This specific absolute platelet counting method is what is common in hospitals and is sold by the kit.

A

Unopette System

36
Q

Aralin niyo na lang yung procedures ng Rees and Ecker, mwa.

A

Go niyo na.

37
Q

What is the purpose of the wet filter paper in the petri dish?

A

To prevent evaporation

38
Q
  • Reference method for platelet counting
  • Uses a phase contrast microscope
  • Uses ammonium oxalate as a diluting fluid
A

Brecher-Cronkite Method

39
Q

The tourniquet should be placed ____ inches or ____ cm above the site of puncture.

A

3 to 4 inches or 7.5 to 10 cm

40
Q

If a touriniquet is unavailable, a BP cuff may be used set to how much pressure?

A

40 to 60 mmHg

41
Q

What is more clinically significant: prolonged or shortened bleeding time?

42
Q
  • The tourniquet should be released within ____
  • It should also be released as soon as ____
A
  • Should be released within 1 minute and as soon as the vein is entered
43
Q

This needle gauge is most commonly used in venipuncture.

A

21 gauge (green)

44
Q

Why is plastic or silicone-coated syringe preferred over glass syringes?

A

Because platelets have clotting factors that activate upon contact with glass

45
Q
  • The choice of coagulant for coagulation studies
  • Has two formulations: 3.2% (0.109 M) and 3.8% (0.129 M)
  • Preserves the labile clotting factors
  • Satisfactory for platelet aggregation studies
  • Ratio of AC to Blood: 1:9
46
Q

Match the following.

  1. Inhibits the fibrinogen-thrombin reaction
  2. Factor V is not stable in its presence
  3. Inactivates thrombin

A. EDTA
B. Heparin

47
Q

What are the two (2) methods in extracting blood for platelet counting?

A
  1. Syringe Method
  2. ETS Method
48
Q

This is the preferred method of collection of blood for platelet counting.

A

ETS method

49
Q

Please read the procedures na lang for blood collection. Alam niyo na yan, malaki na kayo. 😘

A

Go niyo na, mwa.

50
Q

What three (3) changes occur in the sample for platelet counting?

A
  1. Effect of pH
  2. Effect of temperature
  3. Centrifugation
51
Q

Effect of pH

  • If testing is not done immediately, samples should remain?
52
Q

Effect of pH

Platelets are stable for ____, meaning there will be no changes in PT or APTT results.

53
Q

Effect of Temperature

  • ____ and ____ are likely to deteriorate.
A

Factor V and VIII

54
Q

Effect of Temperature

  • ____ and ____ will be prematurely activated at ref temperature (1 to 6 deg Celsius)
A

Factor VII and XI

55
Q

Effect of Temperature

  • Samples should not be frozen if testing can be done within ___
A

Within 2 hours after collection

56
Q

Please memorize the hemostasis specimen storage times and temperature.

A

Thanks, lods.

57
Q

Centrifugation

What type of plasma is required for platelet counting?

A

Platelet-free plasma

58
Q

T or F: Hemolysis should be avoided.

59
Q

PRP or PPP?

  • Sample is centrifuged at 60 to 100 x g for 10 minutes at room temperature
  • Plasma is removed immediately with a plastic or siliconized pipette
  • For platelet aggregation studies
60
Q

PRP or PPP?

  • Applicable for coagulation studies
  • Recentrifuging the sample remaining from the PRP at 2000 x g for 10 minutes
61
Q

What are the six (6) technical errors that may cause hemolysis?

A
  1. Needles with too small bore
  2. Frothing of sample due to entry of air
  3. Excessive stasis through prolonged applicaion of the tourniquet
  4. Expelling blood from the syringe through the needle
  5. Moisture or contamination in the needle, syringe, or blood container
  6. Excessive and vigorous mixing of blood with the anticoagulant
62
Q

Please study the hemostasis specimen collection and management that require specimen rejection.

A

Last na yan, gaur.