Red Cell Morphology

1
Red Cell Morphology
Laboratory Medicine DepartmentSaudi German
Hospital-Jeddah
2
Objectives

• Discuss the procedure for proper red blood cell
  examination
• Discuss aspects of red cell morphology related
  to size
• Discuss aspects of red cell morphology related to
  color
• Discuss different types of poikilocytosis

3
Introduction

• Red cell morphology can be defined as the
  appearance of the erythrocytes on a Giemsa
  stained smear.
• Careful examination of the red cells for the
  purpose of identifying abnormalities is part of
  the differential procedure.

4
Why

• differentiating normal morphology from abnormal
  and artificial morphology.
• provide valuable diagnostic information to the
  physician,
• provide a quality control mechanism to verify red
  cell indices values as determined by automated or
  manual methods.

5
How

• Assess RBC morphology by examining the smear in
  the feathered (thinner) edge where the RBC are
  randomly distributed and, for the most part, lie
  singly, with occasional doublets.
• This area is referred to as the "critical area."

6
How

• If the area is too thin, the red cells will
  appear flat and somewhat square (cobblestone
  effect) with no central pallor.
• If the area examined is too thick, the cells will
  be too close together to evaluate the morphology
  of individual cells.

7
How

• To begin the red cell morphology examination, use
  the low power (10X) objective to locate the
  "critical area."
• The oil immersion objective (100X) is used for
  the actual evaluation.

8
Normal RBCs

• Round, elastic, non-nucleated, bi-concave discs
• Many RBCs have an area of central pallor which
  covers about one-third of the cell.
• The pallor occurs as a result of the disc-shaped
  cells being spread on the slide.

9
Normal RBCs

• Average diameter of 7.2 microns with a range of
  6-9 microns, almost the same size as the nucleus
  of a small lymphocyte,

10
Critical area 10x

• A view of the "critical area" using the low power
  (10X) objective is shown here.

11
Critical area 100x

• Once the correct area has been located on low
  power, switch to oil immersion
• Notice the red cells are lying singly with
  occasional doublets.

12
Too thin

• The area shown in this field is too thin for
  accurate red cell morphology evaluation.
• The cells have large spaces between them, show no
  central pallor and many are somewhat square,
  showing a "cobblestone effect."

13
Too thick

• These cells are in an area which is too thick,
  and should not be used for red cell morphology
  assessment.
• Some of the cells appear to be stacked like coins
  because of the large number of cells present in
  this section of the slide.

14

• The morphology seen in the too thin and too thick
  areas of the smear is referred to as artificial
  morphology.

15
Size Variation
16
Size variation

• Red blood cells can vary in size from smaller
  than normal, microcytes, to larger than normal,
  macrocytes.
• When red cells of normal size, microcytes and
  macrocytes are present in the same field, the
  term anisocytosis is used.

17
Normal size

• Size of normal RBC is almost the size of the
  nucleus of the lymphocyte.

18
Microcyte

• Smaller than a nucleus of the lymphocyte, central
  pallor is greater than 1/3 of the cell

19
Microcyte, increased central pallor
20
Microcyte, normal Hb content
21
Microcytes
22
summary

• microcytes have a diameter of less than 7 microns
  and an MCV of less than 80 cubic microns.
• Two types of microcytes can be seen, those with
  increased central pallor and those with normal
  central pallor.

23
Macrocyte (megalocyte)

• diameter of 9-14 microns (1.5 - 2 times larger
  than normal red cells)
• MCV is 100 cubic microns or more.

24
Megalocytes

• Megalocytes are the result of decreased DNA
  synthesis, frequently due to vitamin B12 and/or
  folic acid deficiencies.
• Decreased DNA synthesis causes the nucleus in the
  developing red cells to mature at a slower than
  normal rate.
• Since hemoglobin production is not affected, the
  mature red cell is larger than normal

25
Macrocytes
26
(No Transcript)
27
Pseudomacrocytes

• appears larger than the lymphocyte but in
  contrast to megalocytes has an area of central
  pallor.
• size is the result of exaggerated flattening and
  thus the presence of the central pallor.
• in patients with cirrhosis of the liver,
  obstructive jaundice, post splenectomy.

28
Psudomacrocytes
29
(No Transcript)
30
Summary

• two types of macrocytes-
• True macrocytes (megalocytes). Increased MCV, MCH
• Pseudomacrocytes. Normal MCV, MCH

31
Anisocytosis

• Increased variation in size of the red cell
  population present on a blood smear.
• Normal, small and large cells can be seen in one
  field.
• Normal MCV, high RDW
• As the severity of the anemia increases, the
  amount of significant anisocytosis present also
  increases.

32
Anisocytosis
33
Anisocytosis
34
RBCs
35
RDW

• RDW is an expression of the homogeneity of the
  RBC population size.
• A large RDW says there's a wide variation in the
  RBC diameters within the test pool. 
• It doesn't say the cells are large or small,
  rather that the population is not homogenous. 
• Younger cells are larger (reticulocytes).
• Older, and generally beat up, RBCs are smaller.

36
RDW
37
Microcytic Anemia
38
Macrocytic Anemia
39
Macrocyte
40
Microcytes
41
Anisocytosis
42
Pseudo-macrocyte
43
Normal
44
Anisocytosis
45
RBC Color
46
RBC Color

• Erythrocytes, when spread on a glass slide, show
  varying degrees of central pallor
• This central pallor is related to the hemoglobin
  concentration present in the red cells.

47
RBC Color

• the central area (1/3 of the cell) is white,
  while buff-colored hemoglobin is visible in the
  outer 2/3 of the cell.
• The MCHC (32-36 gm/dl) is the index value which
  is used to verify the presence of adequate
  hemoglobin concentration in the cells visible on
  the peripheral smear.

48
RBC Color

• A decreased amount of hemoglobin is referred to
  as hypochromasia or hypochromia.
• MCHC values of 30 or less reflect this
  condition.
• Hyperchromasia and hyperchromia, refer to a
  hypothetical situation rather than an actual
  occurrence.

49
RBC Color

• Cells located in the "too thin" portion of the
  smear often appear to be "hyperchromic".
• Megalocytes (macrocytes) are normochromic.

50
Normochromic cells
51
Hypochromic cells
52
Hyperchromia
53
Hypochromia
54
Hyperchromasia
55
Polychromasia
56
(No Transcript)
57
(No Transcript)
58
(No Transcript)
59
Poikilocytosis
60
Poikilocytosis

• Variations in shape.

61
Terminology

• Uniform terminology based on Greek roots

62
(No Transcript)
63
(No Transcript)
64
Grading system

• 1 2 4 /OIF
• 2 5 - 7
• 3 8 - 10
• 4 gt10
• The terms few, moderate, many, and marked may be
  substituted for the 1 - 4 grading system.

65
Acanthocytes

• 3-12 thorn-like projections irregularly spaced
  around the cell.
• Smaller than normal and have little or no central
  pallor.
• Acanthocytes have an excess of cholesterol
• Large numbers of these cells on a smear can be of
  diagnostic significance.

66
Acanthocytes

• Abetalipoproteinemia
• Hereditary acanthocytosis,50 100 of blood
  cells.
• Alcoholic cirrhosis
• lipid disorders
• splenectomy

67
Acanthocyte
68
Codocyte

• Target cells are thin-walled cells showing a
  darkly-stained centre area of hemoglobin which
  has been separated from the peripheral ring of
  hemoglobin.

69
Codocyte

• Codocytes appear in conditions which cause the
  surface of the red cell to increase
  disproportionately to its volume.
• This may result from a decrease in hemoglobin, as
  in iron deficiency anemia, or an increase in cell
  membrane.

70
Codocyte

• Thalassemias, Hb C disease, post splenectomy,
  obstructive jaundice.

71
(No Transcript)
72
Dacrocyte

• Dacryocytes are pear-shaped or teardrop shaped
  cells.
• myelofibrosis/myeloid metaplasia,

73
Drepanocytes

• Drepanocytes or sickle cells are formed as a
  result of the presence of hemoglobin S in the red
  cell.
• As the red cell ages, it becomes less flexible or
  deformable and becomes rigid as it passes through
  the low oxygen tension atmosphere of the small
  capillaries in the body.
• In the absence of oxygen, hemoglobin S
  polymerizes into rods, causing the sickle cell
  shape.
• Sickle cells can be somewhat pointed at the ends,

74

• Most sickled cells can revert back to the discoid
  shape when oxygenated.
• About 10 of sickled cells are unable to revert
  back to their original shape after repeated
  sickling episodes.

75
(No Transcript)
76
Echinocyte (Urchin)

• Echinocytes are reversible,
• The projections are rounded and evenly spaced
  around the cell.
• Acanthocytes have irregularly spaced thorn-like
  projections.

77
Echinocyte

• Uremia,
• Following heparin injection,
• Pyruvate kinase deficiency.
• Artificial

78
Elliptocytes

• Elliptocytes can vary in appearance from slightly
  oval to thin pencil-shaped forms. Less than 1 of
  red cells in normal blood are oval.

79
Elliptocytes

• Hereditary Elliptocytosis
• Thalassemia, megaloblastic anemia, iron
  deficiency.

80
Elliptocytes
81
Elliptocytosis
82
Knizocyte

• A streak of hemoglobin through the centre of the
  cell.
• In some hemolytic anemia cases

83
(No Transcript)
84
Keratocytes

• Keratocytes are cells which have been damaged due
  to contact with fibrin strands.

85

• intravascular coagulation
• microangiopathic hemolytic anemia
• glomerulonephritis
• rejection of renal transplants.

86
(No Transcript)
87
Shistocytes

• Schistocytes are red cell fragments which are
  formed when fibrin strands come in contact with
  circulating red cells. The strands cut a small
  piece from the original cell.

88
(No Transcript)
89
Spherocytes

• cells which have a decreased surface-to-volume
  ratio.
• cell is thicker in diameter than normal red cells
  
• they appear to be round, darkly-stained cells
  without central pallor.

90
(No Transcript)
91
Spherocytes
92

• Hereditary spherocytosis
• Immune hemolytic anemia
• Severe burns
• In-vitro prolonged storage of blood

93
Stomatocytes
94
Stomatocytes

• cup-shaped erythrocytes which have an elongated
  or slit-like central pallor.
• hereditary stomatocytosis, neoplastic disorders,
  liver disease and Rh null disease, in-vitro
  change in pH

95
(No Transcript)
96
(No Transcript)
97
Rouleaux autoaglutination

• Forms of poikilocytosis describing a group of
  cells.
• True and false

98
True Rouleaux
99
True Rouleaux

• most of the red cells, in the proper viewing
  area, are stacked together like coins.
• Four or more cells make up each formation,
  leaving much of the field empty of cells
  (increased white space).
• Rouleaux is clinically significant when increased
  globulins are present, as in multiple myeloma.

100
False rouleaux
101
True rouleaux
102
Artifactual
103
Autoagglutination

• Cells clumping together rather than stacked like
  coins.
• Autoagglutination is caused by the presence of
  antibody in the plasma.

104
(No Transcript)
105

• Match the following terms with their synonyms.
• Target cell
• Helmet cell
• Ovalocyte cell

106

• Match the following terms with synonyms
• Crenated cell
• Tear drop cell
• Sickle cell

107
(No Transcript)
108
(No Transcript)
109
(No Transcript)
110
(No Transcript)
111
(No Transcript)
112
(No Transcript)
113
(No Transcript)
114
(No Transcript)
115
(No Transcript)
116
(No Transcript)
117
(No Transcript)
118
(No Transcript)
119
(No Transcript)
120
(No Transcript)
121
(No Transcript)
122
(No Transcript)
123

• Match the forms of poikilocytosis with the
  physiological/environmental condition associated
  with their formation
• Damaged by fibrin strands
• Absence of abetalipoprotein
• Hemoglobin S

124

• A general term describing variation in size
• anisocytosis
• macrocytosis
• microcytosis
• poikilocytosis

125
(No Transcript)
126
(No Transcript)
127

• helmet cell
• echinocyte
• crenated cell

128
(No Transcript)
129
(No Transcript)
130

• hypochromic
• hyperchromic
• normochromic
• polychromatophilic

131

• macrocytic/normochromic
• microcytic/hypochromic
• normocytic/normochromic
• normocytic/hypochromic

132
(No Transcript)
133
(No Transcript)
134
(No Transcript)
135
(No Transcript)