RBC Anomalies (Part 6) Flashcards
increased number of red cells with VARIATION in SIZE
ANISOCYTOSIS
Diameter of normal RBCs (normocytes)?
7-8 µm
(usually seen when MCV is 80-100 fL)
Four ways to detect anisocytosis:
- Using the NUCLEUS of a small lymphocyte in a peripheralblood smear (PBS)
- Using the MCV value
- Using the RDW value
- Using the RBC histogram
Larger than normal RBCs (diameter > 8.0 µm)
Macrocytes
Associated with impaired DNA SYNTHESIS
BIGGER than the nucleus of lymphocyte
Macrocytes
Macrocytes are seen when value of MCV is?
> 100 fL
Smaller than normal RBCs (diameter < 7.0 µm)
Microcytes
Associated with DEFECTIVE HEMOGLOBIN FORMATION
SMALLER than the nucleus of lymphocyte
Microcytes
Microcytes are seen when the MCV value is?
< 80 fL
Normal erythrocyte = ?
= NUCLEUS of SMALL LYMPHOCYTE
The average volume of individual RBCs?
MCV
Formula of MCV?
Hct / RBC count x 10
Reference range of MCV?
80-100 fL
(Should be consistent with the PBS)
↓MCV = ?
Normal MCV = ?
↑MCV = ?
↓MCV = MICROcyte
Normal MCV = NORMOcyte
↑MCV = MACROcyte
Regardless of the SIZE, the RDW is always __________ in Micro/Macrocytic.
INCREASED
A calculated index (from the RBC histogram) given by hematology analyzers to help identify ANISOCYTOSIS and provide information about its DEGREE (or how severe it is)?
Red Cell Distribution Width (RDW)
Most recent hematology analyzers have provided two methods to calculate the RDW:
- RDW-CV (coefficient of variation)
- RDW-SD (standard devitation)
Based on BOTH the width of the RBC distribution curve and the mean RBC size?
RDW-CV
Based on the actual measurement of the width of the RBC distribution curve in fL (femtoliters)?
RDW-SD
⭐️ RDW-CV reference range for ADULTS:
11.5% to 14.5%
⭐️ RDW-SD reference range in ADULTS?
39 - 46 fL
EARLIEST method provided by the hematology analyzers to measure red cell variations?
RDW-CV
DEPENDENT on the WIDTH of the DISTRIBUTION CURVE and the MCV that is MORE COMMON in the Philippines
RDW-CV
WIDTH of the curve is measured at the point that is 20% ABOVE the baseline
NOT influenced by the MCV
RDW-SD
BETTER and MORE RELIABLE measure of erythrocyte variability, specifically in
HIGHLY ABNORMAL conditions?
RDW-SD
RDW Reference range for newborns?
14.2% to 19.9%
RDW is MARKEDLY INCREASED in newborns but gradually, the value will decrease until it reaches adult levels by 6 MONTHS of age.
If the RBC histogram is ________ than normal, the RDW would be _____________.
WIDER
ABNORMAL
Examples of conditons with their MCV and RDW values:
See INDEX 2
A visual display of CELL SIZE (X-axis) and CELL FREQUENCY or the number of cells
(Y-axis)
Blood cell histogram
provided by many high-volume instruments to provide size distribution of the different cell populations
RBC histogram
Automated hematology analyzers produce histograms for?
RBCs, WBCs, and platelets
TWO parameters calculated from RBC histogram?
MCV & RDW
Instruments being used count those cells with volume sizes as RBCs?
Between 36 fL to 360 fL in size
RBC histogram can measure cells as small as?
24 fL
(However, cells that are counted in the 24 to 36 fL range are NOT included in the RBC count)
LEUKOCYTES are present in the diluted fluid containing RBCs, but their numbers are statistically ____________ in the count.
INsignificant
If the leukocyte count is significantly _________, the RBC histogram will be affected.
ELEVATED
RBC Histogram:
Shift to the RIGHT = ?
MACROcytic
RBC Histogram:
Shift to the LEFT = ?
MICROcytic