(M) Lesson 5: Platelet Count and Function Test (Part 1) Flashcards
Platelet counts are important in helping diagnosing what type of disorders?
Bleeding
Relative platelet count provides what in the peripheral blood?
Estimate number of platelets
Platelets are counted under what objective?
OIO
What is the normal value of platelets?
150,000 to 400,000
Some books say 450,000
How many fields should be counted for platelets under OIO?
10 fields
T or F: Platelets are the same regardless of age group.
False
In newborns, platelets are higher/elevated.
How do we differentiate platelets from debris?
Clue: The unique characteristic of platelets.
Platelets are granulated.
When there is a deficiency of dense granules, platelets appear as?
Pale or gray
Four (4) reagents/equipment needed for platelet count
- Glass slides
- Wright Stain
- Microscope
- EDTA (Blood sample)
Reagents and Equipment
What are the two (2) methods that may be used in staining?
- Quick Staining Method (Dipping)
- Rack Method (Flooding)
Reagents and Equipment
T or F: Capillary blood may be used for platelet count in place of venous blood.
T
However, it is not preferred since it has interstitial fluid and must also be free-flowing.
What are the two (2) types of specimen that may be used for platelet count?
- Whole Blood (venous)
- Blood from heel or fingertip (capillary)
When using capillary blood, you have to wipe away the first drop of blood.
Platelet aggregation may be caused by what?
Traumatic venipuncture
Platelet aggregation caused by traumatic venipuncture causes (falsely decreased/falsely increased) platelet count.
Falsely decreased
Falsely decreased platelet count may be indicative of what two (2) phenomena?
- Pseudothrombopenia
- Pseudoleukocytosis
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)
Platelet satellitosis
Platelet satellitosis may also be caused by non-immunologic factors such as?
Two answers.
- Thrombospondin
- Alpha Granule Proteins
What is the remedy for difficulties such as platelet aggregation and platelet sattelitosis?
- Redraw with citrate
- Perform manual count
- Multiply by 1.1
FIll in the blanks.
- Prepare a ____ and stain it with routine hematological stain.
- Place the prepared slides under the microscope and focus the ____ portion of the smear using the ____ objective.
- Using the ____ method on moving the slide while focused, observe ____ fields and count the total number of platelets seen.
- Get the average platelet per field by dividing the ____ of platelets counted with 10.
- Calculate the relative platelet count using the formula (____)
- Prepare a blood smear and stain it with routine hematological stain.
- Place the prepared slides under the microscope and focus the thin portion of the smear using the oil immersion objective.
- Using the battlement method on moving the slide while focused, observe 10 fields and count the total number of platelets seen.
- Get the average platelet per field by dividing the total number of platelets counted with 10.
- Calculate the relative platelet count using the formula (Relative Platelet Count = Average platelet per field x 20,000)
What are the three (3) different methods in observing fields under the microscope?
- Battlement Method
- Longitudinal Method (Head to Tail)
- Cross-Sectional Method (Edges)
Which part of the blood smear do we count on?
Monolayer
Match the following.
- 0 to 49,000/uL
- 50,000 to 99,000/uL
- 100,000 to 149,000/uL
- 150,000 to 199,000/uL
- 200,000 to 400,000/uL
- 401,000 to 599,000/uL
- 600,000 to 800,000/uL
- 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
- H
- C
- B
- D
- A
- F
- E
- G
Match the following.
- 3 to 10 platelets
- 8 to 20 platelets
A. Per 100 RBC observed
B. Per 150 RBC observed
C. Per 200 RBC observed
- A
- C
What is the manner of reporting for semi-quantitative platelet estimate?
Increase, adequate, or decrease
What are the two (2) methods in manual absolute platelet counting?
- Rees and Ecker Method
- Unopette System
Unopette or Rees and Ecker
Blood Used: EDTA anticoagulated blood
Both
Unopette or Rees and Ecker
- Diluting Fluid Used: Brilliant Cresyl Blue + Formalin + Distilled H2O + Citrate
Rees and Ecker
Note: Those are components of the Rees and Ecker diluting fluid.
Unopette or Rees and Ecker
- Diluting Fluid Used: Ammonium Oxalate
Unopette System
Unopette or Rees and Ecker
- Pipette Used: Either WBC or RBC pipette
Rees and Ecker
Unopette or Rees and Ecker
- Pipette Used: Unopette System
Teh, ewan ko na lang talaga pag nagkamali ka.
Unopette System
Unopette or Rees and Ecker
- Dilution Made: 1:100, 1:20, 1:200
Rees and Ecker
Unopette or Rees and Ecker
- Dilution Made: 1:100
Unopette System
Unopette or Rees and Ecker
- Square Used: Either WBC or RBC squares
Rees and Ecker
Unopette or Rees and Ecker
- Square Used: RBC square
Unopette System
This specific absolute platelet counting method is what is common in hospitals and is sold by the kit.
Unopette System
Aralin niyo na lang yung procedures ng Rees and Ecker, mwa.
Go niyo na.
What is the purpose of the wet filter paper in the petri dish?
To prevent evaporation
- Reference method for platelet counting
- Uses a phase contrast microscope
- Uses ammonium oxalate as a diluting fluid
Brecher-Cronkite Method
The tourniquet should be placed ____ inches or ____ cm above the site of puncture.
3 to 4 inches or 7.5 to 10 cm
If a touriniquet is unavailable, a BP cuff may be used set to how much pressure?
40 to 60 mmHg
What is more clinically significant: prolonged or shortened bleeding time?
Prolonged
- The tourniquet should be released within ____
- It should also be released as soon as ____
- Should be released within 1 minute and as soon as the vein is entered
This needle gauge is most commonly used in venipuncture.
21 gauge (green)
Why is plastic or silicone-coated syringe preferred over glass syringes?
Because platelets have clotting factors that activate upon contact with glass
- 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
Citrate
Match the following.
- Inhibits the fibrinogen-thrombin reaction
- Factor V is not stable in its presence
- Inactivates thrombin
A. EDTA
B. Heparin
- A
- A
- B
What are the two (2) methods in extracting blood for platelet counting?
- Syringe Method
- ETS Method
This is the preferred method of collection of blood for platelet counting.
ETS method
Please read the procedures na lang for blood collection. Alam niyo na yan, malaki na kayo. 😘
Go niyo na, mwa.
What three (3) changes occur in the sample for platelet counting?
- Effect of pH
- Effect of temperature
- Centrifugation
Effect of pH
- If testing is not done immediately, samples should remain?
Unopened
Effect of pH
Platelets are stable for ____, meaning there will be no changes in PT or APTT results.
6 hours
Effect of Temperature
- ____ and ____ are likely to deteriorate.
Factor V and VIII
Effect of Temperature
- ____ and ____ will be prematurely activated at ref temperature (1 to 6 deg Celsius)
Factor VII and XI
Effect of Temperature
- Samples should not be frozen if testing can be done within ___
Within 2 hours after collection
Please memorize the hemostasis specimen storage times and temperature.
Thanks, lods.
Centrifugation
What type of plasma is required for platelet counting?
Platelet-free plasma
T or F: Hemolysis should be avoided.
T
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
PRP
PRP or PPP?
- Applicable for coagulation studies
- Recentrifuging the sample remaining from the PRP at 2000 x g for 10 minutes
PPP
What are the six (6) technical errors that may cause hemolysis?
- Needles with too small bore
- Frothing of sample due to entry of air
- Excessive stasis through prolonged applicaion of the tourniquet
- Expelling blood from the syringe through the needle
- Moisture or contamination in the needle, syringe, or blood container
- Excessive and vigorous mixing of blood with the anticoagulant
Please study the hemostasis specimen collection and management that require specimen rejection.
Last na yan, gaur.