CBC --- Interpretations
Abstract
Interpretation of different parameters reported on
modern day analyzers is bit tricky and demand
continuous monitoring and on-going learning. In
present paper interpretation of different reported
parameters has been discussed with approach to
diagnosis of various abnormalities.
The CBC interpretation are useful in
the diagnosis of various types of
anemias.
It can reflect acute or chronic
infection, allergies, and problems
with clotting.
• Component of the CBC:
• Red Blood Cells (RBCs)
• Hematocrit (Hct)
• Hemoglobin (Hgb)
• Mean Corpuscular Volume (MCV)
• Mean Corpuscular Hemoglobin
Concentration (MCHC)
- Red cell distribution width (RDW)
• White Blood Cells (WBCs)
• Platelet
• RBC (varies with altitude):
– M: 4.7 to 6.1 x10^12 /L
– F: 4.2 to 5.4 x10^12 /L
• Biconcave disc shape with diameter
of about 8 µm
• Function: - transport hemoglobin
which carries oxygen from the lung to
the tissues
-acid –base buffer.
• Life span 100-120 days.
Hemoglobin :
M: 13.8 to 17.2 gm/dL
F: 12.1 to 15.1 gm/dL
Hematocrit : (packed cell volume)
It is ratio of the volume of red cell to
the volume of whole blood.
M: 40.7 to 50.3 %
F: 36.1 to 44.3 %
– MCV = mean corpuscular volume
HCT/RBC count= 80-100fL
• small = microcytic
• normal = normocytic
• large = macrocytic
– MCHC= mean corpuscular hemoglobin
concentration HB/RBC count= 26-34%
• decreased = hypochromic
• normal = normochromic
• MCH (mean corpuscular
hemoglobin)
HB/HCT = 27-32 pg
• RDW (red cell distribution width)
• It is correlates with the degree of
anisocytosis
_ Normal range from 10-15%
• This important value is needed in the evaluation
of any anemia.
• Normal range 1-2%
• Retic count goes up with
– Hemolytic anemia
• Retic goes down with
– Nutritional deficiencies
_ Diseases of the bone marrow itself
Definition of Anaemia
► Decrease
in the number of circulating red
blood cell mass and there by O2 carrying
capacity
► Most common hematological disorder by far
► Almost always a secondary disorder
► As such, critical for all practitioners to know
how to evaluate / determine its cause /
treat
First Question
► The
onset of Anaemia
► Acute versus chronic
► Clues
 Hemodynamic stability
 Previous CBC
 Overt blood loss
Types of Anaemia
Screening Tests – Anaemia
► Clinical
Signs and symptoms of
Anaemia
► Look
for bleeding – all possible sites
► Look
for the causes for anemia
► Routine
► Cut
Hemoglobin examination
off marks for Hb –
 US < 13.5 g
 Subcontinent
WHO < 12.5 g
Less than 12 g%
Clinical Signs to be looked for
►
►
►
►
►
►
►
►
►
►
Skin / mucosal pallor,
Skin dryness, palmar
creases
Bald tongue, Glossitis
Mouth ulcers, Rectal exam
Jaundice, Purpura
Lymphadenopathy
Hepato-splenomegaly
Breathlessness
Tachycardia, CHF
Bleeding, Occult Blood
PCV or Hematocrit
► 57%
► 1%
Plasma
Buffy coat – WBC
► 42%
Hct (PCV)
The Three Basic Measures
Measurement
Range
Normal
A.
RBC count
5 million
B.
Hemoglobin
15 g%
4 to 6
12 to 17
Hematocrit
45
38 to 50
A x 3 = B x 3 = C - This is the rule of thumb
Check whether this holds good in given results
If not -indicates micro or macrocytosis or
hypochromia.
C.
Causes of Anaemia
1.
Decreased production of Red Cells
- Hypoproliferative, marrow failure
2.
Increased destruction of Red Cells
- Hemolysis (decreased survival of RBC)
3.
Loss of Red Cells due to bleeding
- Acute / chronic blood loss
(hemorrhagic)
Anaemia – First Test
RETICULOCYTE COUNT %
• ‘RBC to be’ or Apprentice RBC
• Fragments of nuclear material
• RNA strands which stain blue
Normal
Less than 2%
Reticulocytes
Supravital
Leishman’s
Anaemia
Hb% < 12, Hct < 38%
Hypoproliferative
Hemolytic
Retics < 2
Retics > 2
Normal CBC
Workup – Second Test
► The
next step is ‘What is the size of RBC’ ?
► MCV indicates the Red cell volume (size)
► Both the MCH & MCHC tell Hb content of RBC
► If the Retic count is 2 or less
► We are dealing with either
 Hypoproliferative anaemia (lack of raw material)
 Maturation defect with less production
 Bone marrow suppression (primary/ secondary)
Mean Cell Volume (MCV)
► RBC
volume (rather) is measured by
► The Mean Cell Volume or MCV and RDW
MCV
Microcytic
Normocytic
Macrocytic
< 80 fl
80 -100 fl
> 100 fl
< 6.5 µ
6.5 - 9 µ
>9µ
Anaemia Workup - MCV
MCV
Microcytic
Normocytic
Macrocytic
Iron Deficiency IDA
Chronic disease
Megaloblastic anemias
Chronic Infections
Early IDA
Liver disease/alcohol
Thalassemias
Hemoglobinopathies
Hemoglobinopathies
Hemoglobinopathies
Primary marrow disorders Metabolic disorders
Sideroblastic Anemia
Combined deficiencies
Marrow disorders
Increased destruction
Increased destruction
Red cell Distribution Width - RDW
RDW
Normal
Population
Uniform
High
Population
Double
Anaemia Workup - 4th Test
Peripheral Smear Study
► Are
all RBC of the same size ?
► Are all RBC of the same normal discoid shape ?
► How is the colour (Hb content) saturation ?
► Are all the RBC of same colour/ multi coloured ?
► Are there any RBC inclusions ?
► Are intra RBC there any hemo-parasites ?
► Are leucocytes normal in number and D.C ?
► Is platelet distribution adequate ?
IDA -CBC
Microcytic Hypochromic - IDA
IDA – Special Tests
Iron related tests
Normal
IDA
Serum Ferritin (pmo/L)
33-270
< 33
TIBC (µg/dL)
300-340
> 400
Serum Iron (µg/dL)
50-150
< 30
Saturation %
30-50
< 10
++
Absent
Bone marrow Iron
IDA Summary
►
Microcytic
MCV < 80 fl, RBC < 6 µ
►
RDW
Widened with low MCV
►
Hypochromic
30%
MCH < 27 pg, MCHC <
►
RI
<2
►
Serum ferritin
Very low < 30 (p mols/L)
►
TIBC
Increased > 400 (µg/dL)
►
Serum Iron
Very low < 30 (µg/dL)
►
BM Fe Stain
Absent Fe
►
Response to Fe Rx.
Excellent
IDA- Some Nuggets
Look for occult blood loss – 2 days non veg. free
► Pica and Pagophagia – Ice sucking
► Absorption of Haem Iron > Fe ++ > Fe+++
► Food, Phytates, Ca, Phosphate, antacids ↓absorption
► Ascorbic acid ↑absorption
► Oral iron Rx. always is the best, ? Carbonyl Fe
► FeSO4 is the best. Reserve parenteral Rx.
► Packed cell transfusion in emergency
► Continue Fe Rx at least 2 months after normal Hb
► 1 gram ↑in Hb every week can be expected
► Always supplement protein for the Globin component
►
Microcytic Anaemias
MCV < 80 fl
Serum
Iron
TIBC
BM Perls stain
↓↓
↓↓
↑↑
↑↑
↓↓
0
++
N
++++
Hemoglobinopathy
N
N
Lead poisoning
N
N
++
++
Sideroblastic
↑↑
N
++++
Iron Def. Anemia
Chronic Infection
Thalassemia
Macrocytic Anaemias
A. Megaloblastic Macrocytic – B12 and Folate↓
B. Non Megaloblastic Macrocytic Anaemias
1. Liver disease/alcohol
2. Hemoglobinopathies
3. Metabolic disorders, Hypothyroidism
4. Myelodystrophy, BM infiltration
5. Accelerated Erythropoesis -↑destruction
6. Drugs (cytotoxics, immunosuppressants,
AZT, anticonvulsants)
Anemia - Macrocytic (MCV > 100)
Premature gray hair – consider MBA
Macrocytic anemias may be asymptomatic
until
the Hb is as low as 6 grams
MCV 100-110 fl
must look for other causes of macrocytosis
MCV > 110 fl
almost always folate or B12 deficiency
MBA
Macrocytosis -MBA
HSN - MBA
Basophilic Stippling - MBA
BS occurs in Lead poisoning also
MBA - BM
Pernicious Anaemia - Tongue
Bald, smooth, lemon
yellowish red tongue
Normocytic Anaemias
1.
2.
3.
4.
5.
6.
7.
Chronic disease
Early IDA
Hemoglobinopathies
Primary marrow disorders
Combined deficiencies
Increased destruction
Anaemia of investigations ICU
Anaemia of Chronic Disease
► Thyroid
diseases
► Malignancy
► Collagen Vascular
Disease
 Rheumatoid Arthritis
 SLE
 Polymyositis
 Polyarteritis Nodosa
• IBD
– Ulcerative Colitis
– Crohn’s Disease
• Chronic Infections
– HIV, Osteomyelitis
– Tuberculosis
• Renal Failure
‘Dimorphic’ Anaemia
►
Folate & Fe deficiency (pregnancy, alcoholism)
►
B12 & Fe deficiency (PA with atrophic gastritis)
Thalassemia minor & B12 or folate deficiency
► Fe deficiency & hemolysis (prosthetic valve)
►
►
Folate deficiency & hemolysis (Hb SS disease)
►
Peripheral smear exam is critical to assess these
► RDW
is increased very much
RBC Size – Anisocytosis
Different sizes of RBC
Poikilocytosis
Different Shapes of RBC
Polychromasia - Spherocytosis
Target Cells
1. Liver Disease
2. Thalassemia
3. Hb D Disease
4. Post splenectomy
• WBCs are involved in the immune response.
• The normal range: 4 – 11x10^9 /L
• Two types of WBC:
1) Granulocytes consist of:
– Neutrophils: 50 - 70%
– Eosinophils: 1 - 5%
– Basophils: up to 1%
2) Agranulocytes consist of:
- Lymphocytes: 20 - 40%
– Monocytes: 1 - 6%
The type of cell affected depends upon its primary
function:
In bacterial infections, neutrophils are most
commonly affected
In viral infections, lymphocytes are most
commonly affected
In parasitic infections, eosinophils are most
commonly affected.
•
polymorphneuclear leukocytes
(PMN,s)
• Nucleus 3-5 lobes.
• Diameter 10-14 µm
• 50-70% WBC
=2.5-7.5x10^9/ L
• Function: Phagocytosis of bacteria
and cell debris
• Numbers rise with all manner of
stress, especially bacterial infections
• Neutrophil disorders
– Neutrophilia – an increase in neutrophils
– Conditions associated with neutrophilia are:
1-Bacterial infections (most common cause)
2-Tissue destruction
e.g. tissue infarctions, burns.
3- leukemoid reaction
4-Leukemia
– Neutropenia – this may result from
1-Decreased bone marrow production
e.g. BM hypoplasia.
2-Ineffective bone marrow production
– E.g. megaloblastic anemias and
myelodysplastic syndromes.
3- post acute infection
_ e.g. typhoid fever, brucellosis.
• Bilobed nucleus
• 1-5% of WBC
=0.04-0.4x10^9/L
• Diameter about 10-14 µm
• Function: Involved in allergy, parasitic
infections
• Contains: eosinophilic granules
– Eosinophilia may be found in
• Parasitic infections
• Allergic conditions and
hypersensitivity reaction
• No specific granules
• 20-40% of WBC
=1.55-3.5x10^9/ L
• Diameter 8-10 µm
• T cells: cellular
• (for viral infections)
•
B cells: humoral
(antibody)
•
Natural Killer Cells
•
Lymphocytosis – may indicate
_ Viral infection
e.g. Infectious mononucleosis, CMV or pertussis.
_ Bacterial infection
e.g. TB
• Lymphopenia – caused by
_Stress.
_Steroid therapy
_ Irradiation
• (Leukocytosis) may indicate:
_ Infectious diseases
_Inflammatory disease (such as rheumatoid
arthritis or allergy)
_Leukemia
_Severe emotional or physical stress
_Tissue damage (e.g. necrosis,or burns)
• (Leukopenia) may result from:
_ Decreased WBC production from BM.
_ Irradiation.
_ Exposure to chemical or drugs.
•
•
•
•
Fever
Malaise
Weakness
Others depend on each system which is involved
e.g. » chest: cough, SOB and chest pain
» abdomen: diarrhea, vomiting,
dehydration.
»CNS: headache, visual disturbance,
Neck stiffness
and so 0n.
•
•
•
•
Infection of the mouth and throat.
Painful skin ulceration.
Recurrent infection.
Septicemia.
•Small granular non-nucleated
discs.
•Diameter about 2-4 µm
•Normal range; 150-300x10^9 /L
•Destroyed by macrophage cells in
the spleen.
•Function; involved in coagulation
and blood haemostasis.
•Life span 7-10 days
• Numbers of platelets
– Increased (Thrombocythemia)
•
•
•
•
Pregnancy.
Exercise.
High attitudes.
splenectomy
– Decreased (Thrombocytopenia)
• Menstruation.
• Haemorrhage.
• Bone marrow destruction or suppression e.g. leukemia
• The values have to fit the clinical situation.
• Petechial hemorhage.
• Easy bruising.
• Mucosal bleeding
e.g. _ epistaxes.
_ gum bleeding