LABORATORY ACTIVITY 3 AND LABORATORY ACTIVITY 4 Flashcards
Features of a well-made wedge peripheral blood film
1. The film is (?) the length of the slide
2. The film is (?), (?) at the feather edge, not (?); this provides the widest area for examination
3. The (?) of the film are visible.
4. The film is smooth without (?)
5. When the slide Is held up to the light, the thin portion (feather edge) of the film has a (?).
6. The (?) is picked up and spread.
two thirds to three fourths
finger shaped; very slightly rounded; bullet shaped
lateral edges
irregularities holes, or streaks
“rainbow” appearance
whole drop of blood
: concentrated cell at the middle portion
Too short
The (?), the better distribution
longer
The (?) the tail, the better (more distribution)
wider
: wider and more distribution
Finger
: congested cells
Pointed
: concentrated and big cells may overlap
Bullet
of the edge of the smear and slide should be visible to push the cells outward/sideward
Margination
Causes of holes:
dirty slides and wet slides
Causes of wave-like motion:
flowing or dropping while wet
To know that blood is well-distributed below
“rainbow” appearance.
: inadequate blood
thin
: congested cells
thick
: should not be defined
feather edge
stains:
methanol (fixative), eosin (acidic; negatively charged), methylene blue (basic; positively charged), water (to wash off residue)
Methods
Two-glass method (75 mm x 25 mm)
Spreader slide method
drop of blood:
2-3 mm
angle:
30-45 degrees
(4 factors affecting consistency of smear)
PASS: Pressure, Angle, Size of blood, Speed
(intact rbcs): many rbc (polycythemia), thick and viscous
Inc Hematocrit
: concentrated wbc at the edge
Too slow
Thin PASS
↑ ↓ ↓ ↓
Thick (↑ Hematocrit) PASS
↓ ↑ ↑ ↑
Microscopic examination
- 10x Objective Examination
- 40x High-Dry Objective Lens
- 100x Oil Immersion Objective Examination
- 10x Objective Examination
a. Distribution of cells
b. Edge (transitioning of distribution of cell)
c. Fibrin strands (coagulation and clot formation – improper inversion leading to low rbc and consumed plt)
d. Wbc distribution (should not be concentrated at the edge but throughout the tail)
- 40x High-Dry Objective Lens
a. Evaluation of roleaux formation
b. Wbc estimate
- 100x Oil Immersion Objective Examination
a. Platelet estimate (smaller - needs magnification)
b. Blood cell morphology evaluation
Where to perform
a. In an area where RBC’s has (?)
b. (?) oil immersion field is counted
c. (?) = approximate platelet/mm3
few overlapping
10
Ave no of plt/oil immersion field x 20,000 (standard factor)
Example: 12 to 16 plt/field
Average: 14
14 x 20000 = 280,000 plt/uL
: expect adequate platelet count
• 8-20/OIF
: expect lower platelet count and
• < 5/OIF
: expect higher platelet count
• > 20/OIF
Marked decreased
0 - 49,000
Moderate decreased
50,000 - 99,000
Slight decreased
100,000 - 149,000
Low normal
150,000 - 199,000
Normal
200,000 - 400,000
Slight increase
401,000 - 599,000
Mod. increase
600,000 - 800,000
Marked increased
Above 800,000
The (?) should correlate with the platelet count + 25%. If discrepancy exists, the platelet count and peripheral blood smear estimate should be repeated.
platelet estimate
platelet estimate
Ex. 98,000 x 0.25 = 24,500
110,000
110,000 – 98,000 = 12,000 √
Platelet satelitism will result in (?) platelet counts.
FALSELY DECREASED
Platelet clumping around neutrophil
Platelet satelitism
counted as wbc, not counted as plt
Platelet satelitism
plt ct is lower in
automation
falsely decreased:
automation
no effect:
estimation
reject specimen and redraw blood with (?) (only occurs w/ EDTA)
sodium citrate
(volume correction factor)
ct x 1.1
- time a blood will clot/would will close
Bleeding Time
• Time that takes for a standard wound at a standard pressure to stop bleeding.
Bleeding Time
standard wound (?)
lancet: 2 mm
standard pressure (?)
40mmHg
• Screening test for:
vascular disorder and platelet function defects
Can detect problems in
primary hemostasis
-Standardised incision is made on the
forearm (volar – muscular portion)
-(?): recorded
-(?): recorded
-Compute for minutes it take to stop bleeding
Incision bleeding
Cessation of bleeding
-Result is dependent on:
a. # of platelet
b. ability of platelet to adhere and aggregate to the subendothelium
( fewer platelet = shorter platelet plug =?)
prolonged bleeding time
Earlobe/heel of foot/ fingertip
Duke Method
Forearm
Ivy Method
Template BT (Mielke)
1-3 mins
Duke Method
1-7 mins
Ivy Method
1 puncture
Duke Method
3 puncture
Ivy Method
standard slit
Template BT (Mielke)
Template BT (Mielke) length and depth
11 mm (deep) x 1 mm (long)
Duke Method Advantage
a. Easy to perform
b. Requires minimal equipment -alcohol -lancet -stop watch -filter paper
c. Earlobe is vascular
Duke Method Disadvantage
a. Difficult to standardize the wound
Duke Method equipment
-alcohol
-lancet
-stop watch
-filter paper
Ivy Method Advantage
a. Standardized method
b. More accurate than Duke (less accurate than template bt)
c. Required materials: -lancet -stopwatch -filter paper (cicular, whattmann no. 1) -blood pressure cuff
Ivy Method Disadvantage
a. Not reliable
b. Puncture wound may close before bleeding stops
Ivy Method materials
-lancet
-stopwatch
-filter paper (cicular, whattmann no. 1)
-blood pressure cuff
Template BT (Mielke) Advantage
a. wound can be reproduced from 1 px to another
b. Very sensitive and reproducible
c. Detects even minor alteration in platelet. function
Template BT (Mielke) Disadvantage
a. Scar formation (slit)
Ivy Method Factors affecting
- aspirin intake (pain-reliever)
- fruit intake
- blood thinners (heparin, coumadin)
Ivy Method Sources of Error
-Intake of aspiring (7-10 days) : prolonged BT
-Improper performed instruction (too shallow or deep puncture)
-Residual alcohol
- Prolonged BT
-Proper timing of the bleeding
-Touching of the incision- falsely elevated result
-Improper calibration of stopwatch
Template BT (Mielke) Clinical Significance
Prolonged in:
a. Thrombocytopenia
b. Platelet disorders
c. Afibrogenemia
d. Hypofibrinogenemia
e. Vascular disorders
f. Aspirin
g. Anemia, Leukemia, Liver Diseases
h. VW disease
i. Factor deficiency (Factor V and XI)
Platelet adhesion is affected by:
Calcium, ADP, Fibrinogen
ASPIRIN TOLERANCE TEST
-Aspirin inhibits synthesis of (?), by inhibiting the (?):
Thromboxane A2
Cyclooxygenase
(imp for plt activation; indirect relationship)
Thromboxane A2
-Prolonged BT
ASPIRIN TOLERANCE TEST
ASPIRIN TOLERANCE TEST Procedure:
2 tablets aspirin
2 hours Bleeding Time
-Aspirin is effective within
30 minutes
: BT is doubled
-Normal
: immune to aspirin
1 to 7 mins
: highly sensitive to aspirin
> 14 misn
Prolonged Bleeding time
: when platelet count is lower than 30 - 50, 000/µL or when platelets are dysfunctional.
: in vWD
: after ingestion of aspirin/aspirin-containing compounds, anti-inflammatory, anticoagulants, and some antibiotics
: Puncture is done on the earlobe. bleeding ceases.
Duke method
Duke method Reference value:
1 - 3 mins
: Done on the forearm
Ivy method
Standard pressure applied is 40 mmHg
Ivy method
Ivy method Reference value:
1 - 7 mins.
: Uses a template containing a standardized slit
Template BT (by Mielke)
A properly prepared blood smear is utilized for [?] and for the observation of any abnormal platelet size and distribution.
platelet estimation
Specimen Needed:
Wright- or Giemsa-stained blood smear
- Select an area of the blood film in which most RBCs are separated from one another with [?] and where platelets are not clumped.
- Using the [?], count the number of platelets in [?] consecutive fields, and calculate the average number of platelets per field.
- To obtain the platelet estimate per µL or mm3 of blood, multiply the average number of platelets per field by [?].
- Report the platelet count qualitatively using the following references:
minimal overlapping of RBCs
100x oil immersion objective; 10
20,000
Accurate estimates are possible only when there are no platelet clumps, or at most, rare clumps of [?].
2 to 3 platelets
A better estimate is possible using venous blood with [?] as an anticoagulant, in which platelets are evenly distributed and where clumping normally does not occur.
EDTA
On average, there are [?] per field with [?] red cells.
8 – 20 platelets
200
is the time it takes for a standard wound at a standard pressure to stop bleeding
Bleeding time
This serves as a screening test for detecting disorders of platelet function and the ability of the small blood vessels to control bleeding after injury.
Bleeding time
- Place a blood pressure cuff on the patient’s arm above the elbow.
- Increase the pressure to [?] and hold this exact pressure for the entire procedure.
- Cleanse lateral part of forearm with [?]. Dry.
- Choose an area approximately [?] below the bend of elbow and make [?] skin punctures. Incision must be made parallel to the elbow crease. Note: Avoid underlying subcutaneous veins.
- Start stopwatch as soon as blood appears from the puncture.
- Blot the blood from each puncture with the edge of a filter paper every [?] interval. Note: Care must be taken not to touch the incision.
- End point is when no blood comes out of the punctured area/blood does not stain the filter paper.
- Record the bleeding time of the [?] puncture sites and report the average of the two results.
40 mmHg
70% ethyl alcohol
three finger-width; 2
30 seconds
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