The Erythron Flashcards

1
Q

What are the ways of testing for oygen-carrying capacity in blood?

A

Hb, Hct, RBC count

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2
Q

What are the 3 methods of determining the size of RBC’s? Why?

A

Hct, Hb, RBC count
- confirm degree of anaemias by looking at changes in the same direction and proportion
- determine the avg sie and colour
- unequal changes in 1 of 3 tests compared to the other 2 - determine if it is diagnostic

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3
Q

On rbc indics, how and what effects the MCV, MCHC, and MCH?

A
  • Agglutination: increase MCV
  • Storage: increase MCV, decrease MCHC
  • Turbidity: increase MCH, increase MCHC
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4
Q

What are the parameters used to evaluate reticulocytes?

A

Number
Age
MCH
Reticulocyte Production Index (RPI)

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5
Q

What are the main features of an erythrocyte?

A

Anucleated & full of hemoglobin to carry oxygen

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6
Q

What regulations does an erythrocyte partake in?

A

Acid-base balance
Ion regulation
Managing oxidative stress

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7
Q

What are the 4 main characteristics of an erythrocyte membrane?

A
  • ion transporters
  • cytoskeleton
  • surface glycoprotein antigens
  • deformability & antigenicity
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8
Q

What pathways/pumps are part of the metabolism of an erythrocyte?

A
  • Glycolysis
  • Hexose-monophosphate pathway
  • Methemoglobin reductase pathway
  • NaK ATPase
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9
Q

When is a mitochondria present w/i an erythrocyte?

A

As a reticulocyte or earlier stages

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10
Q

What is the mitochondria used for in a reticulocyte?

A
  • heme synthesis
  • biosynthesis
  • replication
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11
Q

What are the genetic and nutritional deficiencies in RBC metabolism?

A
  1. PFK
  2. PK?
  3. Methb Reductase
  4. Se-GPx
  5. Phosphate
  6. DPG
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12
Q

What mnemonic is used for the oxygen Hb dissociation curve and DPG? What does it stand for and what does it mean?

A

C O2
A cid
D PG
E xercise
T emperature

  • shift right, deliver more oxygen to the tissues
  • shift left, pick up more (aka holding onto more) oxygen
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13
Q

What is the Luebering-Rapoport Pathway?

A

A metabolic pathway in mature erythrocytes involving the formation of DPG

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14
Q

What does DPG do?

A

Regulates oxygen release from hemoglobin and its delivery to tissues

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15
Q

DPG is low in what species?

A

Cats, ruminants

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16
Q

DPG is high in what species?

A

Dog, horse, human, pig

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17
Q

What causes increases in DPG?

A

T3
PK Deficiency
PH increase
Hibernation
Anaemia
Hypoxia

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18
Q

Why don’t ruminants use DPG?

A

They have structurally distint HbF w/ high oxygen affinity that favors oxygen pickup from maternal circulation

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19
Q

Hct is mildly correlated to what?

A

Metabolic rate

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20
Q

What are the 2 ways that RBC’s die?

A
  1. Become senescent as membranes and enzymes fail w/ age –> cleared by splenic macrophages
  2. Rupture to release Hb so the Fe & globin are recycled & bilirubin is excreted
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21
Q

What are the 4 types of Plasma appearance?

A

Colourless
Icteric
Hemolysis
Lipemia

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22
Q

Fibrinogen is what factor in the coagulation cascade?

A

Factor I

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23
Q

Fibrinogen is increased in what processes?

A

Acute inflammation
Necrosis

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24
Q

What is the calculation to determine the concentration of fibrinogen?

A

[Prot (unheated)] - [Prot (heated)] = [fibrinogen]]

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25
Q

Why is lipemia less than ideal?

A
  • interferes w/ spectrophotometric tests, refractometer TP, flame photometric measurements of electrolytes
  • may cause haemolysis
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26
Q

What may cause liipaemia in a blood sample?

A

-recent meal
-pathology

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27
Q

What occurs during hemolysis?

A

Contents of RBC’s is released (ASTT, LDH, +/- K+, inorganic phosphate)

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28
Q

What does hemolysis interfere w/?

A

Photometric tests
Refractometer & enzyme measurements

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29
Q

What is bilirubin?

A

The breakdown product of heme from hemoglobin from senescent or damaged RBCs?

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30
Q

What organ does bilirubin travel to? How??

A

Bilirubin is transported to the liver, bound to albumin

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31
Q

How is bilirubin handled onceit reaches the liver?

A

It is conjugated w/ glucuronic acid in the liver for bile excretion b/c it is highly insoluble

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32
Q

What parameters are affected by bilirubin? How?

A

Increases [ ] of albumin, cholesterol, glucose, TP
Decreases [ ] of creatinine

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33
Q

Increases in Hct and TP =

A

Haemoconcentration (increase rbc in blood, decrease in plasma)

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34
Q

Increase Hct w/ normal TP =

A

Erythrocytosis (polycythemia) - high concentration of RBC in blood (thick blood!)

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35
Q

Decrease hct and TP =

A

Haemorrhagic anaemia - anaemia due to excessive bleeding when loss of RBC exceeds production

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36
Q

Decrease Hct, normal TP =

A

Haemolysis or bone marrow dz

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37
Q

What does an RBC count tell you?

A

Measures oxygen carrying capacity
Number of erythrocytes per L of blood

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38
Q

Using a neubauer haemocytometer, how do you do a RBC count?

A
  • Count WBC in 4 primary corner squares and multiply by 50 to get cells/ microliter
  • count RBC in 5 secondary squares of central primary square and multiply by 10,000 to get cells/microliter
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39
Q

Impedence counters rely on which principle?

A

Coulter principle

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40
Q

What do Laser flow cytometers do?

A

Detect & count individual cells in microdroplets as they pass thru a laser beam. The cells scatter light based on size, nucleus, and cytoplasmic contents

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41
Q

What is CHCM used for?

A

To flag lipemia & hemolysis by comparing against total hemoglobin and comparing size and color

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42
Q

What are red cell indices? What are they used for?

A

RBC count, PCV, [Hb], or direct measure by flow cytometry
Used in anaemic animals (except the horse) to classify anaemia as regenerative or non-regenerative

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43
Q

What metrics are used in red cell indices?

A

MCV, MCHC, MCH

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44
Q

What is MCV? What does it tell you?

A
  • volume of avg RBC in femtolitres
  • Microcytosis, normocytosis, macrocytosis
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45
Q

What does microcytosis suggest?

A

Copper & Iron deficiencies

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46
Q

What does macrocytosis suggest?

A

Regenerative anaemia
Non-regenerative anaemia
Myeloproliferative disorders
Folate deficiency
Poodles
Hereditary stomatocytosis
Hyperthyroidism in cats
Foetals/neonates

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47
Q

What causes spurious macrocytosis?

A

Augoagglutination of erythrocyte
Persistent hypernatremia
Prolonged blood storage prior to assay
Heparin treatment

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48
Q

What occurs in horses that receive heparin treatment for acute laminitis, thrombophlebitis, DIC?

A

Induces agglutination resulting in an increase in apparent MCV, decrease in RBC numbers

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49
Q

Microcytosis can be seen in what conditions?

A

Nutritional: Fe, Cu, B6 Def
PSS
Anaemia of inflammatory disease
Storage depletion of Fe from increased erythropoiesis
Hepatic lipidosis in some cats
Inhibitors of heme synthesis
SIADH
Genetic defects –> Thalassemia, Band 4.1 deficiency, Japanese/korean dogs w/o anaemia, familial dyserythropoiesis in English springer spaniels, hereditary elliptocytosis in dogs

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50
Q

When would you see spurious microcytosis?

A

severely anaemic patients
Persistent hyponatremia in dogs

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51
Q

What do erythrocyte volume histograms do?

A

Reveal increased numbers of microcytes or macrocytes even when MCV is normal

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52
Q

What additional info can be obtained from an erythrocyte histogram?

A

Hb concentration with individual cells –> identifying individual hypochromic cells
Cytogram of volume vs [Hb} of individual cells

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53
Q

How do you determine Red Cell Distribution Width (RDW)?

A

(STD of erythrocyte volumes/mean cell vol) x 100

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54
Q

What is the RDW?

A

Coefficient of variation of erythrocyte volume and an electric measurement of anisocytosis

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55
Q

Increased RDW demonstrates what possible conditions?

A
  • Regenerative anaemias with increased numbers of large reticulocytes
  • Fe deficiency anaemia with increased numbers of microcytes
  • Erythrocyte fragmentation
  • after blood transfusions w/ different sized cells
  • Dyserythropoiesis
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56
Q

When is RDW spuriously increased?

A
  • Erythrocyte agglutination
  • Platelets counted in erythrocyte histogram of severely anaemic patients
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57
Q

What is MCHC?

A

Avg concentration of Hb in an RBC in g/L

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58
Q

How do you calcuulate MCHC?

A

[Hb] (g/L) / PCV (L/L)

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59
Q

MCHC is normally…

A

Hypochromic or normochromic

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60
Q

If MCHC is high, what might this indicate?

A
  • artefact, poor calculations
  • eccentrocytes
  • intravascular hemolysis
  • in vitro hemolysis
  • heinz bodies w/i erythrocytes
  • lipemia
  • erythrocyte agglutination in electronic cell counter
61
Q

What does low MCHC values possibly indicate?

A
  • regenerative anaemias
  • chronic Fe deficiency anaemias
  • hereditary stomatocytosis
62
Q

When does spurious low MCHC values occur?

A
  • aged samples
  • persistent hypernatremia
63
Q

What is MCH?

A

mean cell hemoglobin concentration
The mass of Hb in an avg RBC

64
Q

What is MCH?

A

mean cell hemoglobin concentration
The mass of Hb in an avg RBC

65
Q

How is MCH determined?

A

[Hb]/number RBC

66
Q

CHr is a reliable indicator of…

A

Fe status

67
Q

Reticulocytes come from…

A

The bone marrow, spleen, liver

68
Q

What characteristics are specific to a reticulocyte?

A

Reticulum of aggregates of mRNA, ribosomal protein, mitochondria

69
Q

How can you identify a reticulocyte on a blood smear?

A

‘Big & Blue’
Larger than RBC, basophilic

70
Q

How long does anisocytosis & polychromasia last in reticulocytes?

A

Anisocytosis 7-10d
Polychromasia 1d

71
Q

How do reticulocyte counts differ in species?

A

Cats have aggregate & punctate reticulocytes
Horses have a reduced reticulocyte response

72
Q

The degree of anaemia affects…

A

Reticulocyte %

73
Q

The degree of anaemia shows…

A

-the release of the bone marrow pool
- erythropoietin concentration

74
Q

Reticulocyte counts show…

A

Species
Degree of anaemia
Duration of anaemia
Cause of anaemia

75
Q

In dogs, how long are reticulocytes in the bone marrow?

A

2-3 days

76
Q

If reticulocytes are released after 2-3 d from the bone marrow, what does this indicate?

A

Anaemia

77
Q

In the first 2-3 days following reticulocyte release from BM, haemorrhage or hemolysis appears…

A

Non-regenerating

78
Q

Reticulocytes max out at days _______ from onsset of anaemia

A

5-7 d

79
Q

Reticulocytes are higher in …

A

Younger animals

80
Q

What is RPI?

A

Corrected retiulocyte count / reticulocyte maturation time

81
Q

What are the parameters for RPI?

A

> 2 = a response
About 1 = normal
3 = marked response, especially hemolysis

82
Q

What is the RPI for?

A

Used for release rate && pattern & since intravascular time may change during response to anaemia

83
Q

What are the maturation times for reticulocytes inn dogs and cats?

A

1.5 d in doggo
3 d in kitties

84
Q

Why do we do blood smears?

A
  • check morphology
  • compare smears vs analyser results
  • check for cellular inclusions and parasites
  • differential white ccell counts
85
Q

Why is rapid air dry essential for blood smears?

A

To stop osmosis & cell shrinkage

86
Q

What occurs during cell shrinkage?

A

The fluid concentrates & sucks water out of cells by osmois

87
Q

Where is the monolayer on a smear?

A

Just in from the feather tip whhere half of all cells touch

88
Q

What are common colour changes in RBC morphology?

A

Hypochromasia - increase in central pallor
Polychromasia

89
Q

What size changes can be seen in RBC’s?

A

Anisocytosis (increased RDW)
Macrocytosis
Microcytosis

90
Q

What are some different shapes of RBC that can be seen on a blood smear?

A

Poikilocytosis, echnnocytosis, spherocytosis, acanthocytosis, schistocytosis, elliptocytosis, dacryocytosis, etc

91
Q

What inclusions can be found in RBC’s?

A

Howell-Jolly bodies
Nuclei
Heinz bodies
Basophilic stippling
Infectious organisms

92
Q

What is poikilocytosis in RBC?

A

Abnormal shapes of Rbc

93
Q

What species is it typical to see poikilocytosis?

A

Goats, young cattle

94
Q

Poikilocytosis inclutes what types ofRBC?

A

Echinocytes, spherocytes, acanthocytes, schistocytes, elliptocytes, dacryocytes

95
Q

When does crenation of echinocytes occur?

A

Reversible RBC dehydrationn, ATP depletion, increased pH, increased RBC Ca

96
Q

What non-specific disorders can cause crenation of echinocytes?

A

Snake bites, uremia, post-transfusion, PK deficiency in dogs, neoplasia in dogs, gloerulonephritis, cation depletion (horses)

97
Q

What are some causes of IHA?

A

Idiopathic, neoplasia, infection, toxicity

98
Q

What are some clinical signs of IHA in dogs?

A

Lethargy, inappetance, +/- pigmenturia, tachycardia, pale MM, fever

99
Q

How do you Dx IHA in dogs?

A

Hct <25-30%
Hemolysis (Hbemia, Hburia, bilirubinemia)
RBC antibodies (agglutination, spherocytosis, Coomb’s positive)

100
Q

What is the rate of survival for dogs w/ IHA?

A

28-70% dies in 1st 2 wks
73% live 0.5 year
51% live 1 yr

101
Q

What are predictors of mortality in IHA in dogs?

A

Azotemia, icterus, thrombocytopaenia, petechiae

102
Q

What are some predilections of IHA in dogs?

A

Breeds: maltese, Viszla, airedale, spinger, Irish terrier, Irish setter, cocker, poodle, rough collies, mini schnauzer
Age: middle-aged females

103
Q

What is spherocytosis?

A

Smaller, darker, rounder rbc w/ no central pallor that are spherical in shape and osmotically fragile

104
Q

What are some characteristics specifito spherocytes?

A

Decreased surface area to vol ratio
Increased Hb conc
No central pallor
Increased osmotic fragility
Decreased deformability

105
Q

What condition might you commonly see spherocytes?

A

Immune-mediated hemolytic anaemia

106
Q

Is IHA usually intravascular or extravascular?

A

Extravascular

107
Q

What do the macrophages do in extravascular IHA? Where do they come from?

A

Job: phagocytose RBCs coated w/ IgG
From: liver, spleen, bone marrow

108
Q

Partial phagocytosis in extravascular spherocytes results in…

A

Spherocytes w/ increased erythrocyte osmotic fragility

109
Q

Intravascular hemolysis in IHA is instigated by … & leads to…

A

From: IgG coating & complement activation
Leads to: Hbemia, Hburia, ghost cells (lysed rbc)

110
Q

Is IHA always intravascular or extravascular?

A

No, can be both

111
Q

What causes autoagglutination?

A

Increased amounts of IgG and IgM coated on RBC & spherocyte surface cross link

112
Q

What test can autoagglutination interfere with?

A

Coomb’s test

113
Q

IMHA often results in

A

Agglutination of rbcs

114
Q

What is the Coomb’s test?

A

Autoglobulin test for IHA

115
Q

Explain the Coomb’s test

A

RBCs w/ immunoglobulin or complement have an antiglobulin reagent added to if agglutination occurs

116
Q

What are acanthocytes?

A

Thorn or spur shaped RBCs

117
Q

When are acanthocytes most common?

A

Liver dz, hemangiosarcoma, DIC, glomerulonephritis

118
Q

What is a unique characteristic of acanthocytes?

A

Increased membrane cholesterol

119
Q

What are schistocytes?

A

Split cells (aka rbc fragments)

120
Q

What diseasses would have schistocytes present?

A

DIC, PSS, Fe deficiency anaemia, glomerulonephritis, vasculitis

121
Q

What family of animals normally has elliptocytes?

A

Camelidae

122
Q

If elliptocytes are present in a cat, what diseases are you suspicious of?

A

Bone marrow abnormalities
Hepatic lipidosis
PSS
Doxorubicin toxicity

123
Q

If elliptocytes are present in a dog, what diseases might be on your differential list?

A

Myelofibrosis
Myelodysplastic syndrome (MDS)
Glomerulonephritis
RBC band 4.1 deficiency

124
Q

What are dacrocytes?

A

Tear-drop cells

125
Q

When might dacrocytes be present?

A

MPD in dogs/cats
Glomerulonephritis in dogs
Hypersplenism in dogs
Fe deficient ruminants
Myeloid metaplasia/metastatic neoplasms to the Bone marrow
TB

126
Q

What are Howell-Jolly Bodies

A

Micronuclei

127
Q

What species have low numbers of HJBs normally?

A

Horses, cats

128
Q

HJB’s increase during what type of anaemia?

A

Regenerative anaemia

129
Q

What are 3 other times the HJBs might occur?

A

Splenectomy, glucocorticoids, vincristine therapy in regenerative anaemia

130
Q

How do HJB’s form?

A

When a chromosome is lost or breaks during final mitosis of a rubriblast to an erythrocyte

131
Q

Nucleated erythrocytes are typically what stages of erythrocyte development?

A

Metarubricytes and rubricytes

132
Q

When might nucleated erythrocytes be present?

A

Regenerative anaemia
Pb toxicity
Bone marrow injury/disease
Cardiovascular dz, trauma, hyperadrenocorticism in dogs
Splenic disfunction
Hereditary dyserythropoiesis (dogs/cattle)

133
Q

Aside from anaemia, when else might bone marrow injury occur?

A

Septicaemia, endotoxic shock, drugs

134
Q

What are some marrow diseases that may occur with non-regenerative anaemia?

A

Myelodysplasia, hematopoietic neoplasms, infiltrative disorders

135
Q

When do you see Heinz body anaemia?

A

Onion poisoning

136
Q

Heinz body anaemia is present when there is … on thhe rbcs

A

Oxidized hb

137
Q

When are heinz bodies present in small animals?

A

Some feline diseases - diabetes, lymphoma, hyperthyroidism
Splenectomy (dogs)
Onion ingestion
Propylene glycol in soft-moist cat foods (less common)
Zn toxicity (dogs)
Acetaminophen, methylene blue, methionine, phenazopyridine, menadione (Vit K3) ingestion

138
Q

When are heinz bodies present in large animals?

A

Wild & domestic onion ingestion - livestock
Kale & other Brassica sp. Ingestion - ruminants
Lush winter ryegrass ingestion - FL cattle
Se-Def cattle on St. Augustine Grass
Post-parturient NZ cattle on pyrennial ryegrass
Red maple leaf consumption - horses
Cu toxicity - sheep/goats
Phenothiazine - horses

139
Q

When would eccentrocytes be present on a blood smear?

A

Onion, garlic poisoning
T-cell lymphoma
Ketoacidosis
Severe infection

140
Q

When might ghost cells occur in vivo?

A

Immune-mediated
Oxidant-induced
Enzymatic
Osmotic

141
Q

What other ways might lysed erythrocytes appear on a smear?

A

In vitro hemolysis
Smudged cells

142
Q

What is basophilic stippling?

A

Diffuse pattern of aggregates of ribosomes & polyribosomes

143
Q

When would basophilic stippling occur?

A

Pb toxicity
Regenerative anaemia in ruminants

144
Q

What are some common infectious protozoal organisms of rbcs?

A

Babesia
Theileria
Cytauxzoan sp

145
Q

What rickettsial organisms invade rbcs?

A

Anaplasma spp

146
Q

What mycoplasmal organisms invade rbcs?

A

Haemobartonella spp, eperythrozoon sp

147
Q

What bacterial organism invades rbcs?

A

Bartonella spp

148
Q

What viral organism invades rbcs?

A

Distemper

149
Q

What infectious agents invade blood but not rbc’s?

A

Trypanosoma spp
Clostridium haemolyticum
Leptospira spp