topic 5 Flashcards
-Acceptable working area should contain at least ______
leukocytes (if WBC count is not less than 4.0 x 109 /L)
300
Indicates presence of abnormal serum globulins (coin stacked)
ROULEAUX FORMATION
Presence of certain antibodies to RBC surface antigens (grape
like)
AGGLUTINATION
Seen in Spherocytosis
HYPERCHROMIC
seen in IDA, thalassemias,etc
HYPOCHROMIC
Term used to describe the variation in Hb
content when both hypochromic and normochromic cells are
present
ANISOCHROMASIA
Indicates the average volume of a single erythrocyte in a given
blood sample
-Expressed in SI units as FEMTOLITERS
MEAN CORPUSCULAR VOLUME (MCV)
Indicates the average WEIGHT of Hb per erythrocyte
-Expressed in SI as PICOGRAMS (1pg = 10-12g)
MEAN CORPUSCULAR
HEMOGLOBIN (MCH)
Variation in red cell population size or diameter Should be
estimated semi-quantitatively: SLIGHT, MODERATE, MARKED
MICROCYTES VS MACROCYTES Correlated with the RANDOM
DISTRIBUTION WIDTH (RDW)
ANISOCYTOSIS
Normal RBCs show little or no shape variation
POIKILOCYTOSIS
provide the number of cells in one axis and the
cell size on another axis.
histograms.
plot various degrees of light scatter on the
vertical and horizontal axes to classify cells based on the
nuclear and cytoplasmic characteristics of light scatter.
SCATTERGRAMS
obtained by plotting the cell size, nuclear
structure and surface, and internal characteristics within a
three dimensional matrix.
scatterplots
are values calculated from the erythrocyte count, the
hemoglobin, and the hematocrit.
RBC INDICES
-Provides the average size of red blood cells
- If there is an equal proportion of large and small erythrocytes,
the average would be normal.
- The random distribution width (RDW) is the standard
deviation of the red cell size divided by the average red cell size
(MCV), hence is an accurate measure of anisocytosis.
MEAN CORPUSCULAR VOLUME
- Provides the average hemoglobin per cell.
- This does not however take into account an abnormal cell
size.
MEAN CORPUSCULAR
HEMOGLOBIN
Factors in the hematocrit in order to account for cell size and
provide a more accurate value of hemoglobin level of each cell.
MEAN CORPUSCULAR
HEMOGLOBIN
CONCENTRATION
- Presence of clots
-Wrong testing temperature - Tube inappropriately filled
- Hemolysis, lipemia, and cold agglutinins
Pre-analytical factors:
Increased incidence of two cells passing through the aperture
because of a high count.
-Presence of other “interfering cells” such as pyknotic cells,
nucleated RBCs, basket and smudge cells, and
micromegakaryocytes
Analytical factors:
Wrong encoding
Post-analytical factors
- The erythrocytes being counted are measured for their size and this information is recorded for calculation of the
hematocrit and generation of the histogram. - The number of cells and the size of the cells are used for the
computation of hematocrit. - The manual hematocrit may be 2% higher than the automated
hematocrit due to the plasma trapped between the cells tested.
HEMATOCRIT
