topic 5

Question 1

-Acceptable working area should contain at least ______
leukocytes (if WBC count is not less than 4.0 x 109 /L)

Answer 1

300

Question 2

Indicates presence of abnormal serum globulins (coin stacked)

Answer 2

ROULEAUX FORMATION

Question 3

Presence of certain antibodies to RBC surface antigens (grape
like)

Answer 3

AGGLUTINATION

Question 4

Seen in Spherocytosis

Answer 4

HYPERCHROMIC

Question 5

seen in IDA, thalassemias,etc

Answer 5

HYPOCHROMIC

Question 6

Term used to describe the variation in Hb
content when both hypochromic and normochromic cells are
present

Answer 6

ANISOCHROMASIA

Question 7

Indicates the average volume of a single erythrocyte in a given
blood sample
-Expressed in SI units as FEMTOLITERS

Answer 7

MEAN CORPUSCULAR VOLUME (MCV)

Question 8

Indicates the average WEIGHT of Hb per erythrocyte
-Expressed in SI as PICOGRAMS (1pg = 10-12g)

Answer 8

MEAN CORPUSCULAR
HEMOGLOBIN (MCH)

Question 9

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)

Answer 9

ANISOCYTOSIS

Question 10

Normal RBCs show little or no shape variation

Answer 10

POIKILOCYTOSIS

Question 11

provide the number of cells in one axis and the
cell size on another axis.

Answer 11

histograms.

Question 12

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.

Answer 12

SCATTERGRAMS

Question 13

obtained by plotting the cell size, nuclear
structure and surface, and internal characteristics within a
three dimensional matrix.

Answer 13

scatterplots

Question 14

are values calculated from the erythrocyte count, the
hemoglobin, and the hematocrit.

Answer 14

RBC INDICES

Question 15

-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.

Answer 15

MEAN CORPUSCULAR VOLUME

Question 16

• Provides the average hemoglobin per cell.
• This does not however take into account an abnormal cell
  size.

Answer 16

MEAN CORPUSCULAR
HEMOGLOBIN

Question 17

Factors in the hematocrit in order to account for cell size and
provide a more accurate value of hemoglobin level of each cell.

Answer 17

MEAN CORPUSCULAR
HEMOGLOBIN
CONCENTRATION

Question 18

• Presence of clots
  -Wrong testing temperature
• Tube inappropriately filled
• Hemolysis, lipemia, and cold agglutinins

Answer 18

Pre-analytical factors:

Question 19

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

Answer 19

Analytical factors:

Question 20

Wrong encoding

Answer 20

Post-analytical factors

Question 21

• 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.

Answer 21

HEMATOCRIT