Peripheral Smear

Sarmishtha Ghosh

Physiology

CBC

• TOTAL RBC COUNT

• TOTAL WBC COUNT

• PERIPHERAL SMEAR– SHAPE, SIZE & COLOR OF RBCs– DIFFERENTIAL WBC COUNT– PLATELET COUNT

• HEMOGLOBIN CONCENTRATION

• BLOOD INDICES – MCH, MCV, MCHC

1

4

2

3

Normal RBC distribution

HEAD- TOO THICK, SMALL & HYPOCHROMIC

TAIL- TOO THIN, MACROCYTIC & FLAT

SHAPE

HEMOGLOBIN CONTENT & DISTRIBUTION

WHITE BLOOD CELLS- LEUCOCYTES

NEUTROPHIL

EOSINOPHIL

BASOPHIL

LYMPHOCYTE

MONOCYTE

Hemocytometer

Blood Indices

• The relationships between the hematocrit, the hemoglobin level, and the RBC are converted to red blood cell indices through mathematical formulas.

• These formulas were worked out and first applied to the classification of anemias by Maxwell Wintrobe in 1934.

• The indices include these measurements: mean corpuscular volume (MCV); mean corpuscular hemoglobin (MCH); mean corpuscular hemoglobin concentration (MCHC); and red cell distribution width (RDW). They are usually calculated by an automated instrument as part of a complete blood count (CBC).

Mean corpuscular volume (MCV)

• MCV is the index most often used. • It measures the average volume of a red blood

cell by dividing the hematocrit by the red blood cell count.

• The MCV categorizes red blood cells by size.

• Cells of normal size are called normocytic, smaller cells are microcytic, and larger cells are macrocytic. Following formula is used to calculate MCV

Mean corpuscular hemoglobin concentration (MCHC)

• measures the average concentration of hemoglobin in a red blood cell.

• This index is calculated by dividing the hemoglobin by the hematocrit. The MCHC categorizes red blood cells according to their concentration of hemoglobin.

– Cells with a normal concentration of hemoglobin are called normochromic;

– cells with a lower than normal concentration are called hypochromic.

– Because there is a physical limit to the amount of hemoglobin that can fit in a cell, there is no hyperchromic category.

• Anemias are categorized as hypochromic or normochromic according to the MCHC index.

Mean corpuscular hemoglobin (MCH)

• The average weight of hemoglobin in a red blood cell is measured by the MCH.

• Anemias are categorized as hypochromic or normochromic or hyperchromic according to MCH index.

• MCH is most useful in diagnosis of severely anemic patients. Among those with lesser degrees of anemia, it is less useful because the measurement has a potential for a relatively wide range of error.

• MCH (in pg) = hemoglobin (in g/dL) x 10 ÷ RBC count (in millions/mm3)

Normal results for red blood cell indices are as follows:

• MCV 82 to 98 fl (femtoliters)

• MCHC 31 to 37 g/dl (or %)

• MCH 26 to 34 pg (picograms)

LAB EXERCISES

References cellbio.utmb.edu/microanatomy/Blood.htm

Constructed by:Dr. Sarmishtha Ghosh

MBBS2012

IDENTIFY WITH JUSTIFICATION : a,b,c,d1

a b c de f

2

• 1) What is the advantage of the biconcave shape of RBCs?

• 2) Why is the absence of a nucleus an advantage?

3

R- Red Blood Cell

N- Neutrophil

E- Eosinophil

• 1) What is the function of N & E respectively?

• 2) The eosinophil count of a patient is 7%. What might be the probable indications?

4

R- Red Blood Cell

N- Neutrophil

E- Eosinophil

• Identify “X”.

• What is it composed of?

• What is its function in the body?

X

5

• The photograph shows a Monocyte

• What made you identify it to be a Monocyte?

• Where would you expect monocytes to be in an infection?

• What is their function?

6

• These cells in the are 25-33% of white blood cells.

• What is it and what is its function?

7

• Identify Cell # 1

• Identify Cell # 2

• Identify Cell # 3

8

•This is a Lymphocyte.

•State the Identifying features

•Is this a T lymphocyte or a B- lymphocyte

9

Comment on RBCs in the three slides A,B and C.

10 A

B C