3. Collection of blood for different
investigations
CBC, we use sequestrene or EDTA
as anticoagulant.
Coagulation studies, we use
citrated plasma( trisodium citrate )
i.e. anticoagulated sample.
4. Definition of EDTA
An abbreviation of
Ethylenediaminetetraacetic
acid, which is also known as
edetate, versene, or
sequestrene. EDTA binds to
and makes unavailable metal
ions in a solution (a chelator).
5. Blood indices
PCV “packed cell volume” or the
hematocrit (HCT) is the proportion of
blood volume that is occupied by RBCs. It
is normally about 48% for men and 38%
for women
MCV can be calculated (in litres) by
dividing the hematocrit by RBC count
(PCV/ RBC).
The result is typically reported in
femtolitres.
6. Blood indices.. cont
MCH "mean cell hemoglobin", is the
average mass of hemoglobin per RBC=
Hgb/RBCs.
MCHC “mean corpuscular hemoglobin
concentration” is a measure of the
concentration of hemoglobin in a given
volume of packed RBC (Hgb/ PCV).
7.
8. Anaemia, definition
Anaemia can be defined as a
reduction in the haemoglobin
concentration to below 11.5 g per
decilitre in an adult male and below
11.0 g per decilitre in an adult
female.
Anaemia is not a disease in itself,
but may reflect an underlying
disease process. It may also result
from an increase in plasma volume
and a dilutional effect - for example,
as occurs during pregnancy.
9. Classification by blood film
In adults:
microcytic anaemia - MCV < 76
femtolitres, IDA, Thalassemia
normocytic anaemia - MCV = 76-96
femtolitres
macrocytic anaemia - MCV > 96
femtolitres, MA
11. Normocytic anaemia
This is anaemia where the mean
cell volume is within the range of
76-96 femtolitres.
The most usual cause is anaemia
of chronic disease. However, if
there is a reduced white cell count
or reduced platelet count then
suspect bone marrow failure -
diagnosis will require the
performing of a bone marrow
biopsy.
12. Classification by cause
Anaemia may be subdivided into three
broad categories of underlying
pathology:
Increased loss: haemorrhagic
Anaemia
Increased rate of destruction of red
blood cells: haemolytic Anaemia
Reduced production of red blood cells,
with hypercellular bone marrow
17. Approach to a patient with anaemia
History, onset, duration and progress
Age & sex. Common in children and
pregnant women.
Occupation, farmers, chemicals …
Drug ingestion
Clinical examination
Investigations:
Complete blood count (including
platelet count and reticulocyte count)
with red cell indices (MCV, MCH and
MCHC) and examination of peripheral
blood smear
18. Examination of the bone marrow
Cellularity
General screening for trails,
megakariocytes. Myeloid and
erythroid cells, maturation and ratio.
Macrophages and their content.
Plasma cells
Malignant cells e.g. blast cells
Parasites. Extrahaemopeitic tissue.
Iron stain. Special stains.
22. Prussian blue iron stain demonstrates the blue granules of hemosiderin
in hepatocytes and Kupffer cells.
23. Bone marrow iron stain (Perl’s Stain)
normal
stain,
Iron
depleted
stain,
Iron
24. Investigations… cont
According to the type of
anaemia
e.g. IDA, serum iron MA serum B12,folate
Haemoglobinopathies
Haemoglobin electrophoresis
AIHA, HDN, Coombs test
Spherocytosis, Osmotic fragility etc
39. Anaemia in pregnancy
The mean minimum value for haemoglobin
accepted by the World Health
Organisation is 11.0 g/dl (at sea level). A
woman with haemoglobin levels below this
value that occur during pregnancy has, by
definition, anaemia in pregnancy.
Anaemia in pregnancy is more common in
patients who are already anaemic at
conception e.g. patients with
haemoglobinopathies, poor diet, with a
history of menorrhagia. Women with a
multiple pregnancy are more prone to the
development of anaemia.
41.
During the antenatal period Hb
estimation are routinely taken
at booking, 28, 32 and 36
weeks. An iron deficiency
anaemia will exhibit a low
serum iron and raised total
iron binding capacity, with a
hypochromic microcytic film
and low serum ferritin.
Anaemia in pregnancy.. cont
42. So either Iron deficiency anaemia
or Folate deficiency anaemia
Physiological anaemia occurs in
pregnancy because blood volume
increases to a greater extent than
red cell mass, thus leading to a
reduction in blood viscosity and
resulting in a dilutional anaemia.
Supplements of iron and folate
are given
43.
The importance of a fall in Hb
during pregnancy, indicating a
healthy plasma volume
expansion, has been
appreciated for some time
A cohort study revealed lowest
perinatal mortality was
associated with a lowest
recorded maternal hemoglobin
concentration of between 9-11
g/dL).
)
44. Anaemia in neonates
Neonatal anaemia is not a
diagnosis, it is a sign that there
is an underlying pathology
taking place.
As with adult anaemia, the
implication is that there is an
increased breakdown, an
increased loss, or a decreased
manufacture of red blood cells.
45. Aetiology
Increased blood loss may be the result of:
Prenatally:
Placenta praevia
Cord rupture
Foeto -maternal or foeto -placental bleed
Twin-twin transfusion. Postnatally:
Haemorrhage in the neonate, for example
as a result of trauma or coagulopathy
iatrogenesis - phlebotomy in sick
neonates
46. Aetiology “cont”
Increased breakdown may be the result
of:
Haemolytic disease of the newborn
Haemolytic disease of the newborn:
Haemolytic disease of the newborn is said
to occur when haemolysis of a neonate's
red blood cells is caused by antibody from
the mother. This condition only occurs
where there is incompatibility between the
maternal and foetal blood.
47.
One of the most severe causes of
this condition is rhesus
incompatibility.
Other causes include, in descending
order of frequency and severity:
Rhesus incompatibility tends to be
more severe than ABO
incompatibility because anti-D
antibodies are mainly IgG, which can
readily cross the placenta, whereas
anti-A and anti-B antibodies are
mainly IgM, which cannot cross the
placenta.
48. Investigations in haemolytic disease of the
newborn
If haemolytic disease of the newborn is suspected,
the following investigations should be carried out:
Full blood count, with attention to haemoglobin,
white cells, platelets and reticulocytes.
Infant blood group and Coombs test
Maternal blood group and haemolysins
Red cell enzyme assay may be a helpful second
line investigation
Blood film and osmolar fragility may diagnose
spherocytosis
50.
The Coombs' test is used in the investigation of
haemolytic anaemia.
A positive Coombs' test is found in cases of
autoimmune haemolysis due to the presence of IgG,
complement or both, on the surface of the patient's
red cells.
The principle of the Coombs' test is that addition of
rabbit anti-human IgG to the patient's blood will result
in aggregation of the patient's red cells if the red cells
are coated in autoreactive IgG.
If antisera specific for complement components are
added to the patient's blood the presence of
complement on the red cells may be demonstrated.
Coombs' test
