[LESSON 1] Platelet Counting
Crystal Violet (stain) 40% formalin 0.2 mL Sodium citrate 100 mL
Guy and Leake's method diluting fluid composition
2000
Guy and Leake's method's correction factor
Colorless, refractive bodies
Platelets appear _________ in Ammonium oxalate method
Lilac refractive bodies
Platelets appear as _____________ in Guy and Leake's method
Azure granules with scantly light blue cytoplasm
Platelets appear as ________________ when stained
Light blue
Platelets are stained _________ in Rees-Ecker method
Dust Dirt Bacteria Other debris
Platelets cannot be easily differentiated from _______, _______, _______, and _______
Brilliant Cresyl Blue (stain) 0.1 gm 40% formalin 0.2 mL Sodium citrate 100 mL
Rees-Ecker method diluting fluid composition
No. of cells/mm3 = cells counted x 2000
Rees-Ecker method formula
First 30 minutes
Some diluted specimen is only stable for the _____________
1. Platelet count simply platelet aggregation and clotting 2. Imperfect sources of blood 3. Procedure during blood collection 4. Blood in EDTA kept at 20 C is satisfactory only within 5 hours after collection 5. Some diluted specimen is only stable for the first 30 minutes
Sources of error in platelet counting
Punctured
The reservoir in the unopette system is _________ to open access to the reagent
Unopette method
A method that utilizes a premeasured volume of diluent in a chamber into which a specified amount of blood is drawn
<100 platelets
(Brecker-Cronkite method platelet count) Add more squares until 100 platelets are recorded
>50 platelets
(Brecker-Cronkite method platelet count) In 50 RBC squares, repeat procedure with 1:20/1:10 dilution with WBC pipette
>10 platelets
(Brecker-Cronkite method platelet count) Repeat mixing and charging to verify the test
Unopette system
A system of prefilled blood dilution vials containing solutions that will preserve certain cell types while lysing others
+- 10 platelets
Allowable platelet difference on each counting chamber in Brecker-Cronkite method
No. of cells/mm3 = cells counted x 1000
Ammonium oxalate method formula
EDTA
Anticoagulant used in platelet counting
5 hours
Blood in EDTA kept at 20 C is satisfactory only within _______ hours after collection
Ammonium oxalate
Diluting fluid used in Ammonium oxalate method
1% Ammonium oxalate
Diluting fluid used in Brecker-Cronkite method
1:100 dilution
Dilution of Ammonium oxalate method
1:100 dilution
Dilution of Brecker-Cronkite method
1:200 dilution
Dilution of Rees-Ecker method
Rees-Ecker Guy and Leake's Brecker-cronkite Uniopette Van-Allen's
Direct methods of platelet counting
25 RBC squares only
In Guy and Leake's method, platelets are counted in __________
All tertiary 25 squares of the central secondary square with 1mm2 area
In the Ammonium oxalate method, platelets are counted in ______________
All 10 RBC squares of each counting chamber (total of 20 RBC squares)
In the Brecker-Cronkite method, platelets are counted in ______________
All tertiary 25 squares of the central secondary square with 1mm2 area
In the Rees-Ecker method, platelets are counted in ______________
Type of capillary used
In the unopette method, dilution is determined by the _________ since each type have different volumes
Hemocytometer chamber
In the unopette method, the diluted blood is added to a _____________ and cells are counted in a specified area
Dameshek Fonio's Olef Smear estimation
Indirect methods of platelet counting
Platelets
They are characterized by a tendency to aggregate and adhere to foreign surfaces
Platelets
They are small, anucleate, colorless, moderate refractile bodies
Unopette test system
This consists of a self-filling capillary pipette; a straight, thin-wall, uniform-bore plastic capillary tube fitted into a plastic holder; and a plastic reservoir containing a premeasured volume of reagent for diluting
True
True of False: Platelets adhere to glass surfaces / any foreign body
True
True or False: Platelets integrate easily when exposed to air