Examination of Peripheral Blood Film and Correlation with the Complete Blood Count Flashcards
A peripheral blood film provides valuable information regarding a patient’s health; hence, it should be:
- well-made;
- well-stained; and
- carefully examined.
the “capstone” of the Complete
Blood Count (CBC)
PBF
PBF specimen
FRESH WHOLE BLOOD samples collected in EDTA
liquid form in glass tubes; mixes readily with blood
Tripotassium EDTA (K3EDTA)
powdered or spray-dried form in plastic tubes
Dipotassium EDTA (K2EDTA)
Blood should be processed within
4 hours
what happens when Plasma hypertonicity occur?
RBCs will shrink
- Platelets surround or adhere to neutrophils
- This in-vitro phenomenon results in falsely
decreased platelet count (pseudothrombocytopenia)
Platelet satellitosis
- Platelets aggregate to form masses of similar
size to WBCs - This in-vitro phenomenon results in falsely
elevated WBC count (pseudoleukocytosis)
Platelet agglutination
are samples collected without anticoagulant
- FRESH CAPILLARY (capillary or skin puncture)
- VENOUS BLOOD (venipuncture syringe method)
The easiest to master, the most convenient, and the most commonly used technique for making peripheral blood film
MANUAL WEDGE TECHNIQUE
Manual wedge technique glass slides measurement
3-inch x 1-inch (75mm x 25mm)
Blood drop size
2 to 3mm
angle of spreader slide
30 to 45 degrees
Other factor to consider the angle of spreader slide
- Extremely low hct:
- higher hct:
- Extremely low hct: angle needs to be RAISED
- higher hct: angle should be LOWERED
Acidic (or anionic) dye:
Basic (or cationic) dye:
- Eosin
- Methylene blue
The force of attraction or repulsion between unlike and like charges, respectively.
Coulombic attraction
fixes the cells to the slide:
Methanol
stains basic components,
e.g., hemoglobin and eosinophil granules →
“eosinophilic” or “acidophilic”
Acidic (anionic) dye: Eosin
stains acidic components, e.g., nucleic acids (DNA and RNA) and basophil granules → “basophilic”
Basic (cationic) dye: Methylene blue
buffer solution
Phosphate buffer (0.05M sodium phosphate, pH 6.4)
MACROSCOPIC EXAMINATION
PBF has holes all over the film:
increased blood lipid levels (lipemia)
MACROSCOPIC EXAMINATION
PBF has a grainy appearance:
RBC agglutination (cold agglutinin disease)
MACROSCOPIC EXAMINATION
PBF has blue specks at the feathery edge:
markedly increased WBC and platelet counts
MACROSCOPIC EXAMINATION
PBF appears too blue:
increased blood protein levels (multiple myeloma, gammopathy)
is the best possible area of the peripheral blood film where morphology assessments are
performed
Zone of Morphology
is a “panel” essentially divided into RBC, WBC, and Platelet parameters, which are interpreted together to provide the best information.
CBC
OPTIMAL ASSESSMENT AREA
RBCs are uniformly and singly distributed,
with few touching or overlapping, and have their normal biconcave appearance (central pallor)
Optimal area
OPTIMAL ASSESSMENT AREA
This distorts RBCs and WBCs by piling them on top of one another, making morphologic
evaluation difficult and potentially incorrect classification.
Too-thick area
OPTIMAL ASSESSMENT AREA
The film has holes, and the RBCs look
flat, large, and distorted.
Too-thin area
