LABORATORY DIAGNOSIS OF
ANAEMIA IN PREGNANT WOMEN
ANNETTE MOBIT
B.M.L.S (HONS.)
LABORATORY SCIENTIST
MEDICAL AND HEALTH SERVICES
CDC
INTRODUCTION
• A knowledge of a patient’s symptoms and
clinical history can often establish the cause of
anaemia.
• Laboratory tests can help to identify the type of
anaemia and monitor patient’s response during
treatment.
• Techniques for measuring haemoglobin and
assessing anaemia will also depend on available
faculties and resources the Laboratory has in
place.
TECHNIQUES FOR
DIAGNOSING
ANAEMIA IN PREGNANCY
• Haemoglobin Measurement.
• Packed cell volume (haematocrit) measurement
• Red cell indices
• Blood films Examination
• Electrophoresis to detect Haemoglobin sickle
cells.
• Reticulocyte count
• Platelet count
DIAGNOSIS CONT.
• Platelet count
• WBC count
• Stool examination.
• Urinalysis
Haemoglobin Measurement
• Anaemia occurs when the conc. of Hb falls
below what is normal for a person’s age,
gender and environment. Hb values are
expressed in grams per litre (g/dl) or
grams per decilitre (g/dl). Hb reference
range will also depend on the method
used, manufacturer’s produces and
reference range.
Hb Normal reference
ranges
• Children at birth
• Children (2-5) yrs
• Children (6-12)yrs
• Adult men
• Adult women
• Pregnancy women
13.5-19.5g/dl.
11.0-14.0g/dl.
11.5-15.5g/dl.
13.0-180g/dl.
12.0-15.0g/dl.
11.0-13.8g/dl.
Measurement Techniques
• Haemoglobin can be measured using two
techniques.
• Photometric Techniques.
• Here the absorbance of Hb in blood sample is
measured electronically using filter colorimeter
or read out Hb meter.
• Visual comparative Technique
This is use when it is not possible to measure
Hb accurately using a photometric technique
e.g -Who Haemoglobin colour scale.
Packed cell volume (PCV) or
Haematocrit Measurement
• Packed cell vol (PCV) is the
proportion of whole blood
occupied by red cells expressed
as a ratio PCV is also used to
calculate red cell indices, which
are also used to investigate
anaemia.
PCV VALUES
• Pcv values vary according to age,
gender and attitude, pcv is measured
in litre.
• Children at birth
0.44-0.54l/l
• Children (2-5) yrs
0.34-0.40l/l
• Children (6-12)yrs
0.35-0.45l/l
• Adult men
0.40-0.54l/l
• Adult women
0.36-0.46l/l
Measurement of Red cell indices.
• Red cell indices frequently used to investigate
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•
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•
•
anaemia are:
Mean cell haemoglobin conc.(MCHC).
This gives the conc of Hb in gll in 1litre of
packed red cells. That is calculated from Hb and
PCV
MCHC = Hb
(g/l)
Pcv (l/l).
Normal Range – 315-360gll (31.5-36.0)gldl.
MCHC, MCV
• Mean red cell volume (MCV)-This gives the
red cell size. It is determined from PCV
and electronically obtained RBC count.
• MCV = PCV L/L = MCV fl.
RBC x 1012/L
fl= 10-15 /L
• Mean cell haemoglobin (MCH) –This gives
the amount of Hb in an average red cell. It
is determined from the Hb and RBC.
• MCH = Hb g/L = MCH pg
RBC x 1012/L
pg = 10-12 /L
EXAMINATION OF BLOOD FILMS
• This include thin blood films from finger
pricking or bone marrow smear.
• Examination using thin blood films is
important in the investigation and
management of anaemia which produce
changes in the appearance of red blood
cells and differential white cell count.
• Analysing thin blood film includes the
following:
EXAMINATION OF BLOOD FILMS
CONT.
• Differential white cell count and white cell
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•
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morphology.
Red cell morphology.
Platelets.
A differential white cell count provides information
on the different white cells in the circulating blood,
That is
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils (rarely seen).
Differential WBC reference range
for adults.
• Cells
Percentages
• Neutrophils_______________40-75 %
• Lymphocytes______________21-40
• Monocytes________________ 2-10
• Eosinophils________________ 1-6
• Basophils_________________ 0.1-1
Children
Cells
Percentages
• Neutrophils_______________20-45
• Lymphocytes______________45-70 %
• Monocytes________________ 2-10
• Eosinophils________________ 1-6
• Basophils_________________ 0.1-1
Red Cell Appearance
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•
Size and Shapes.
Normocytic – Normal red cell measuring about
8Nm in diameter.
Microcytic – smaller than normal red cells
having diameter less than 6.5Nm seen in iron
deficiency anaemia.
Macrocytic – Larger than normal red cells with
diameter greater than 8Nm seen in Folate, vit
B12 def anaemia.
Sphecrocytosis – small densely staining
spherical red cells with no central pallor
Red Cell Appearance Cont.
• Anisocytosis – unequal variation in the size of
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•
•
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red cells. Seen in many anaemia’s.
Pencil cells – Elongated narrow red cells seen in
iron deficiency anaemia.
Sickle cell – Elliptical cells with pointed ends or
cresent shaped or boat shape cells. Seen in
sickle cell anaemia.
Schistocytes – Irregularly contracted red cell
fragments often with projections
seen in red cell damage due to burns, drugs,
toxins, uraemia, and pre-eclampsia
Red Cell Appearance Cont.
• Poikilocytosis – significant variation in cell
shape seen in many anaemia’s.
• Reticulocytes (Nucleated Red cells)Nucleus in red cell seen in sickle cell
diseases.
• Megaloblast – Larger than normal red cells
between (10-20) Nm with an immature
nucleus with fine lacy chromatin pattern.
seen in megaloblastic anaemia (def of
Colour of Red blood cell
(Haemoglobinization).
• Hypochromic – Pale staining red cells with
increased area of central pallor.
seen in ferrus def anaemia.
• Polychromasia – Blue –grey staining of
immature red cells which are larger than
normal red cells. Seen in haemolytic
anaemia.
Platelets count
• This can be requested to investigate
mucosal bleeding with a decreased in
platelet count usually below 20x109 /L
• Normal value 150-400x109/L
• An increased in platelets count can be
seen in iron def anaemia associated with
active bleeding
White Blood cell count
• can be used to investigate infections
Normal range in pregnancy 4-15x109 /L
• leukopenia (decrease in WBC) can be seen
in -Aplastic anaemia,
• Folate and vit B12 deficiency
(megaloblastic anaemia).
Other non frequent Anaemia
investigations
• Stool Examination.
For hook – worm ova. Microscopy for stool wet
preparation and fecal occult blood test.
Severe hook worm infection may lead to iron
deficiency anaemia.
Liver function Test
Yellowish plasma to detect Bilirubin conc.
• Urinalysis
Blood in urine is an indication of haemolysis.
Summary of red cell indices in
common anaemia’s.
Ref value
Anaemias.
Normocytic
Normochromic
–
•
MCHC
MCV
MCH.
31.5-36.0gldl. 80-98fl 27-32pg.
N
• Microcytic
Hypochromic
e.g Fe def.
• Macrocytic
N
N
N
THANKS
FOR
YOUR
KIND
ATTENTION.