Blood Smear Flashcards
:SPECIMEN OF CHOICE
ANTICOAGULANT-FREE BLOOD
• LAVENDER (PURPLE) - TOPPED TUBES
• Contain…
disodium or tripotassium ethylenediameteraccetic acid (EDTA)
• PREFERRED EDTA
LIQUID TRIPOTASSIUM (K3) EDTA
Time limit for blood smear preparation
• Made within____ of drawing the specimen
•_____= have unacceptable blood cell artifacts
4 hours
> 5 hours
ADVANTAGE using EDTA
• Multiple slides can be made
• Do not have to be prepared immediately
• Prevents platelets from clumping on the glass slides
The quality of these smears depends heavily on the…
source of collection and the handling of the specimen.
Why Anticoagulant-Free Blood?
• The absence of anticoagulants allows for optimal preservation of cellular morphology.
• It prevents artifacts that can be introduced by chemical additives.
Liquid Tripotassium (K3) EDTA is the preferred form of EDTA for hematological studies because it:
• Provides better anticoagulation.
• Reduces platelet clumping.
• Preserves cellular morphology.
is an in vitro phenomenon where platelets surround or adhere to neutrophils, forming clusters.
Platelet satellitosis
Platelet satellitosis
Causes…
Causes pseudothrombocytopenia in automated hematology analyzers.
• Platelet count appears falsely low (since platelets are not counted independently).
• White blood cell (WBC) count appears falsely high (pseudoleukocytosis) as the analyzer may count platelet-bound neutrophils as WBCs.
How to Eliminate Platelet Satellitosis?
• Recollect the specimen using sodium citrate tubes (light blue top).
• Mix blood in a 9:1 ratio (blood to sodium citrate).
• Perform manual platelet count or peripheral smear review to confirm findings.
FINGER AND HEEL PUNCTURES
These are capillary blood collection methods, commonly used in:
• Neonates and infants (heel puncture).
• Adults when venous access is difficult (finger puncture).
FINGER AND HEEL PUNCTURES
Advantages
• Smears can be made immediately at the patient’s side, reducing processing delays.
• Useful for patients with difficult venous access.
FINGER AND HEEL PUNCTURES
Disadvantages
• Platelet clumping: Capillary blood tends to have platelet aggregation, which can lead to inaccurate platelet counts.
• Limited sample volume: Only a few slides can be made directly from skin puncture blood, limiting repeat testing.
Advantage and disadvantage sodium citrate tubes
Eliminates platelet satellitosis
Dilution effect requires correction
Dilution factor for sodium citrate
1.11
• Easiest to learn and perform.
• Most commonly used method in hematology laboratories.
Manual Wedge Technique
Manual blood smear
• Requires two clean glass slides (size L x W).
3 inches × 1 inch
Uses a drop of blood approximately______
2–3 mm in diameter
Spreader slide is positioned at a _____angle to ensure a smooth and even smear.
30–45°
IMPORTANT
The entire drop of blood must be__________ to prevent uneven distribution of cells.
picked up and spread evenly
Types of Wedge Techniques
1. ________– The spreader slide pushes the blood forward.
- _________– The spreader slide pulls the blood backward.
Push-type wedge
Pull-type wedge
Steps for Making a Blood Smear
- Clean the slides – Ensure both the base slide and spreader slide are clean and dry to prevent artifacts.
- Place an appropriate drop of blood (2–3 mm in diameter) near one end of the slide.
- Maintain a consistent 30–45° angle while spreading the blood using a second slide as the spreader.
- Move the spreader slide in a smooth, quick motion all the way to the end of the film.
5. Apply even, gentle pressure to the spreader slide to avoid ridges or waves.
- Ensure the smear has a feathered edge with a gradual transition from thick to thin.
- Allow the smear to air-dry completely before staining —do not blow on it or use artificial heat.
- Use the correct staining procedure (e.g., Wright-Giemsa stain) to ensure accurate cell visualization.
- Label the slide properly with patient identification details.
Smear too thin or too long
Drop of blood too small
Spreader slide at too low an angle
Improper speed in making smear
