The Complete Blood Count

Question 1

How is hemoglobin measured?

Answer 1

Spectrophotometrically. They lyse RBC and convert hemoglobin to cyanmethemoglobin and measure the absorbance of wavelengths at 525 or 540nm.

Question 2

Define: Hematocrit

Answer 2

Volume of whole blood is occupied by red cells.

Question 3

How do you calculate hematocrit?

Answer 3

Hct (%)= (RBC X MCV)

Question 4

True or False: Red blood cells are fairly constant throughout life.

Answer 4

False. Physiological variables affect one’s RBCs include age, sex, and altitude.

Question 5

What is erythrocytosis?

Answer 5

More than the expected number of red cells for one’s age

Question 6

How does an aperture impedance work?

Answer 6

An electrical current is established across an aperture when cells pass through and causes a voltage surge. Pulses are directly related to the size of the cell.

Question 7

What is mean corpuscular volume?

Answer 7

The average volume of a red blood cell

Question 8

How do you calculate MCV?

Answer 8

MCV= ((HCT * 10)/ RBC)

Question 9

What is Mean Corpuscular Hemoglobin?

Answer 9

The MCH is the content (weight) of Hgb of the average red cell

Question 10

How do calculate MCH?

Answer 10

MCH = Hgb / RBC

Question 11

What is mean corpuscular hemoglobin concentration?

Answer 11

Average concentration of Hgb in a given volume of packed red cells

Question 12

How do you calculate MCHC?

Answer 12

(Hgb/Hct) * 100

Question 13

What is red cell distribution width?

Answer 13

Measure of the variation in size of the red cells and will be proportional with the width of the histogram. It is expressed as a percentage.

Question 14

What are reticulocytes?

Answer 14

Immature red blood cells that retain mRNA and ribosomes. 1-2 days afterr being released from bone marrow they lose RNA and organelles

Question 15

What stain can you use to visualize reticultocytes?

Answer 15

Supravital stain- it aggregates the ribosomes and other organelles

Question 16

How do you express nucleated RBCs?

Answer 16

Nucleated RBCs / 100 WBCs

Question 17

Do platelets vary with sex or age?

Answer 17

No

Question 18

What is it called when you have too few platelets?

Too many?

Answer 18

Thrombocytopenia

Thrombocytosis

Question 19

What is measured using an impedance transducer?

Answer 19

RBC, Hct, PLT

Question 20

When are white counts the most variable?

Answer 20

In childhood. They don’t very much after puberty

Question 21

What is measured using a flow cytometer?

Answer 21

Platelets, Nucleated RBC, Percent white cells, reticulocyte percent, and heme progenitor cells

Question 22

What do mononuclear cells refer to?

Answer 22

Lymphocytes and Monocytes

Question 23

Describe the appearance of neutrophils.

Answer 23

Cytoplasm: Acidophilic with fine granules
Nucleus: Clumped chromatin with 2-5 distinct lobes connected
Too few: Neutropenia
Too many: Neutrophilia
*The most abundant adult white cell

Question 24

Describe the appearance of lymphocytes

Answer 24

Cytoplasm: Very scant cytoplasm
Nucleus: Round dense chromatin
Too few: Lymphopenia
Too many: Lymphocytosis

*Most abundant white cell in young children

Question 25

Describe the appearance of monocytes

Answer 25

Cytoplasm: ample grayish-blue
Nucleus: Irregular and lobulated
Too few: Monocytopenia
Too many: Monocytosis

The largest cells

Question 26

Describe the appearance of eosinophils.

Answer 26

Cytoplasm: Spherical granules are large, course and reddish orange
Nucleus: Bi-lobulated
Too many: Eosinophilia

Question 27

Describe the appearance of basophils.

Answer 27

Cytoplasm: purple-black, course granules
Nucleus: obscured
Too many: basophilia

Least abundant of all white cells in the peripheral blood

Question 28

Describe the appearance of platelets.

Answer 28

Cytoplasm: fine granules

small fragments