rbc counting Flashcards
T/F The erythrocyte number concentration refers to the number of erythrocytes contained in 1 liter of blood
T
In traditional units, the erythrocyte count is expressed as __________ (unit)
num of cells per cubic mm
What can the result of an RBC count help diagnose?
Blood-related conditions such as anemia and polycythemia.
blood test that tells us of how many RBC we have
RBC count
system used as a manual method for counting RBCs that includes a dilution tube
unopette system
T/F unopette system requires pre-measuring the diluting fluid.
F - solution or diluting fluid is already pre-measured and ready
Select: Unopette system
A. Introducing the blood sample
B. Mixing completely for a homogenous mixture
C. Charging and counting using the same metho
D. Aspirating the sample without diluent
ABC
Select: Manual methods for counting RBCs
A. Microscopic (pipette method)
B. Automated analyzers
C. Unopette system
D. Tube dilution
A C D
The __________ method is a manual microscopic method for counting RBCs.
pipette
The use of __________ has significantly improved the precision of RBC counting
automated analyzers
T/F: Automated analyzers have virtually replaced manual methods for counting RBCs due to their inaccuracy and questionable necessity.
F - replaced manual methods due to their accuracy and greater precision
Select: RBC Thoma pipette
A. Aspirate to 0.5-1.0
B. Bulb = 100 units
C. Blue bead
D. Smaller bore
E. Dilution factors 200 or 100
A B D E
The anticoagulated blood used in the pipette method is typically contained in a __________ top tube.
lavender (edta)
Select: Good RBC diluting fluid
A. High specific gravity
B. Easy to prepare
C. Promotes mold growth
D. Cheap
E. Buffer action
A B D E
T/F The RBC Thoma pipette has a blue bead inside the bulb.
F - red bead inside the mixing chamber
maximum volume that the bulb of an RBC pipette can hold
100 units
T/F A thick coverslip is used to ensure that 0.2 mL of diluted solution or blood is placed in each of the large squares of the chamber.
F - 0.1 mL
The improved Neubauer counting chamber is used to count cellular components such as RBCs, WBCs, or __________ cells.
sperm
The diluting fluid for RBC counting must be an __________ solution to maintain cell integrity
isotonic
Dacie’s/Formol Citrate is composed of 10.0 mL of __% solution of ____ and 990 mL of __% W/V _____
40% formaldehyde
3% trisodium citrate.
Situation: Aspirate blood to the 0.5 mark of the RBC pipette. What is the dilution factor?
1:200 (0.5/100 x 2 = 1:200)
T/F hypotonic solution is recommended for RBC counting as it helps to preserve cell integrity.
F - would lyse or swell the RBCs
specific gravity of RBCs
1.097
Aspirate blood to the 0.1 mark of the WBC pipette. What is the dilution factor?
1:100
T/F Dacie’s/Formol Citrate is considered the best RBC diluting fluid because it alters cell shape.
F - does not alter cell shape kaya siya best
diluting fluid allows for the growth of yeast and produces clumping of cells
Hayem’s
Gower’s diluting fluid contains __________ gm of glacial acetic acid.
16.65 gm
T/F Gower’s solution prevents rouleaux formation, which is often observed in infections.
T
Select: Hayem’s diluting fluid
A. Allows growth of yeast
B. Produces clumping of cells
C. Can stand for long periods
D. Has corrosive effects
A B C - no corrosive effect
purpose of Toisson’s diluting fluid
stain WBCs to aid in the differentiation of WBCs from RBCs
composition of 3.8% Sodium Citrate
sodium citrate + distilled water
Select: components of Toisson’s diluting fluid
A. Sodium Chloride
B. Glycerine
C. Sodium sulfate
D. Methyl violet
E. Formaldehyde
A B C D (*methyl violet is for staining)
Situation: You have a blood sample that exhibits excessive rouleaux formation. Which diluting fluid would you use to address this issue?
Normal Saline Solution - effctive for excessive rouleaux formation
t/f while aspirating the diluting fluid, the pipette should remain stationary to ensure accurate measurement
F - pipette should be rotated continuously while aspirating the diluting fluid
T/F Toisson’s diluting fluid should be filtered regularly to prevent the growth of fungi.
T
Bethell’s diluting fluid contains 5 gm of ____
sodium sulfate
mark to which you should aspirate blood when using a RBC pipette
0.5 mark
T/F Normal saline solution is used primarily in emergency cases and excessive rouleaux formation.
T
What position should the pipette be in while mixing the contents after aspiration?
horizontal
drawing the diluting fluid up to the __________ mark indicates a dilution factor of 1:200.
101 mark
The first step in preparing diluted blood is to __________ the EDTA tube or blood sample before aspirating.
Mix
T/F you can aspirate blood directly from the EDTA tube or transfer it to a clean vessel.
T
Select: preparation of diluted blood
A. Wipe off excess blood at the tip of the pipette
B. Draw the diluting fluid up to the 101 mark
C. Aspirate blood at the 1.0 mark
D. Rotate the pipette while aspirating the diluting fluid
a b d - aspirate blood to 0.5 mark
To ensure a homogenous solution, secure the pipette using your __________ and __________.
thumb nd middle finger
Situation: You have mixed the EDTA tube and are ready to aspirate blood. What mark should you aspirate the blood sample to?
0.5 mark
T/F Excess blood should be wiped off the tip of the pipette to avoid contamination
t
T/F Before charging the counting chamber, it’s important to ensure that both the coverslip and counting chamber are free from contamination.
t
before charging, you must reshake the __________ and discard the first 5-6 drops.
pipette
What should be placed before charging the counting chamber?
thick coverslip
The counting chamber should be filled by __________ action or the Hanging Drop Technique.
capillary
When charging the counting chamber, the angle of the pipette should be 60-70 degrees
F - 30-35 degrees
how long should the counting chamber stand before making the count?
5-10 mins
Select: Discarded first 5-6 drops from the pipette
A. They contain the diluted blood mixture.
B. They are cell-free.
C. They may contain contaminants
D. They are the most accurate measurement
B
After allowing the counting chamber to stand, stage it into the __________ to proceed with counting the RBCs.
microscope
Count the RBCs in all squares of the counting chamber without following any specific pattern
F - systematic way
what is the systematic order for counting RBCs in the counting chamber?
1st row - Left to Right, 2nd row - Right to Left, 3rd row - Left to Right, 4th row - Right to Left
Select: RBCs included in the count
A. RBCs touching the top and left borders
B. RBCs touching the right and bottom borders
C. RBCs inside the tertiary square
D. RBCs outside the tertiary square
A C
After counting the cells in the 5 tertiary squares, the cell difference between two squares must be __________ or less.
20
t/f all counts must be done in DUPLICATE to improve accuracy and precision.
t
done if the difference in cell count between two squares exceeds 20 cells
repeat count
SITUATION
Square 1: 35 cells
Square 2: 28 cells
Square 3: 34 cells
Square 4: 30 cells
Square 5: 55 cells
repeat
Square 1: 25 cells
Square 2: 20 cells
Square 3: 22 cells
Square 4: 21 cells
Square 5: 45 cells
repeat
formula for rbc count
rbc count (no of cells/cumm) = Total No. cells counted / Area x depth x dilution.
The depth of the counting chamber used for RBC counting is ______ mm
0.1 mm
dilution factor used in the RBC count calculation
1/200 dilution (101 mark)
Select: Parts of the RBC Count formula
A. Total No. cells counted
B. Area
C. Depth
D. Temperature
E. Dilution
A B C E
Select: Sources of error in manual RBC counting
A. Overcharging the counting chamber
B. Using a clean, dry RBC pipette
C. Not discarding the first few drops
D. Counting air bubbles
A C D
If the total number of cells counted is 100 in a 1/5 area, what is the RBC count?
= RBC Count = Total No. cells counted / Area x depth x dilution
- RBC Count = 100 / (1/5) x (1/10) x (1/200)
- RBC Count = 100 / (1/10,000) = 1,000,000 cells/cumm
Calculate the RBC count if the total number of cells counted is 150
RBC Count (No. of cells/cumm) = Total No. of cells counted x 10,000
150 x 10,000 = 1,500,000 cells/cumm
T/F The reference range for RBC count in males is 3.0-5.5 M/cumm.
F - 4.5-6.0 M/cumm.
reference range for RBC count in females
4.0-5.5 M/cumm.
SI unit for RBC count
x10^12/L
OOO: reference ranges for RBC count
A. Male: 4.5-6.0 M/cumm
B. Female: 3.0-5.0 M/cumm
C. Late Pregnancy: 3.0-5.0 M/cumm
D. At Birth: 7.0 M/cumm
B - 4.0-5.5 M/cumm
Select: Sources of error in manual RBC counting
A. Overcharging the counting chamber
B. Using a clean, dry RBC pipette
C. Not discarding the first few drops
D. Counting air bubbles
A C D
Select: Sources of error in manual RBC counting
A. Incorrect aspiration/dilution
B. Discarding the first few drops from the pipette
C. Presence of air bubbles upon charging
D. Performing the count without allowing RBC to settle
A C D
One source of error in RBC counting is the presence of __________ in the counting chamber.
dirt / debris
T/F Using old or unfiltered diluting fluid may lead to the growth of bacteria
F - lead to growth of fungi or the presence of yeast
when RBC count is markedly increased, the volume of aspirated blood should be ______, and a new dilution factor should be calculated
decreased
You aspirated blood to the 0.5 mark in an RBC pipette and counted 200 cells.
RBC count = ?
RBC Count = 200 x 10,000 = 2,000,000 cells/cumm
T/F If there is an undercharged chamber, this will result in an overestimation of RBC count.
F (undercharging = underestimation)
If you aspirate blood up to the 0.1 mark on an RBC pipette, what will be the dilution factor?
1:1000
term used when fluid overflows into the moats during RBC counting
overcharging
T/F For patients with decreased RBC counts, you should aspirate a larger volume of blood.
T
Situation: If you aspirate blood from 0.3 to 1.0 on the RBC pipette, what is the dilution factor?
The dilution factor = Volume of blood / (100 - 1)
Dilution factor = 0.3 / 100 = 1:333.33
Men have ____ RBC counts than women
higher
T/F: Newborns generally have lower RBC counts than adults.
F - higher
strenuous activities result in increased RBC counts due to ____
dehydration
Select: Increased RBC counts
A. High altitudes
B. Chronic dehydration
C. Sedentary lifestyle
D. Strenuous activities
A B D
condition characterized by an abnormal increase in RBC count
polycythemia
T/F Anemia is associated with increased RBC counts.
F - decreased RBC counts (oligocythemia)
other pathologic conditions that cause variations in RBC counts
Hemorrhage, drugs, secondary to other disorders/disease
principle behind the photoelectric method of RBC counting
solution turbidity
In the photoelectric method, the more turbid the solution, the ____ cells are present in the solution.
more
T/F photoelectric method is more accurate than the manual method
T
The principle behind automated analyzers for RBC counting is __________.
Electronic Impedance/Flow Cytometer/Coulter principle
Situation: RBC count for a Male patient reveals a total of 800 cells counted for all 5 tertiary cells. Dilution was 1:200 using an improved Neubauer counting chamber. What is the Total RBC count? Evaluate the result based on normal ranges.
Total RBC count = (Total No. cells counted) / (Area x Depth x Dilution)
Total RBC count = 800 / (1/5 x 1/10 x 1/200) = 800 x 10,000 = 8,000,000 cells/cumm
Normal range for males: 4.5-6.0 M/cumm. The result is markedly increased.
Situation: A sample for RBC count was done using a 1:200 dilution. You counted the following numbers on the 5 tertiary squares:
R1: 94
R2: 87
R3: 91
R4: 85
R5: 98
Calculate the Total RBC count.
Total = (94 + 87 + 91 + 85 + 98) = 455 cells
Total RBC count = 455 x 10,000 = 4.55 M cells/cumm or 4.55 x 10^12/L
Situation: lab technician performs an RBC count and records the following counts from the tertiary squares:
R1: 110
R2: 115
R3: 108
R4: 130
R5: 122
Dilution: 1:20
repeat count
Situation: A sample for RBC count was done using a 1:200 dilution. You counted the following numbers on the 5 tertiary squares:
R1: 94
R2: 87
R3: 91
R4: 85
R5: 98
Calculate the Total RBC count.
Total = (94 + 87 + 91 + 85 + 98) = 455 cells
Total RBC count = 455 x 10,000 = 4.55 M cells/cumm or 4.55 x 10^12/L
Situation: Sample for RBC count was done using a 1:200 dilution. The technician counted the following in the 5 tertiary squares:
R1: 90
R2: 92
R3: 89
R4: 91
R5: 94
Calculate the Total RBC count.
Total RBC Count: 456 / (1/5 x 1/10 x 1/200)
Total: 456 x 10,000 = 4.56 M cells/cumm
Normal Range: Male: 4.5-6.0 M/cumm, Female: 4.0-5.5 M/cumm
