HAEMATOLOGICAL

EVALUATION OF ANEMIASitalakshmi S

Professor and Head

Department of Clinical Pathology

St John’s medical College, Bangalore

Learning Objectives

Laboratory tests for the evaluation of anemia

Classification of anemia

Common causes of anemia in OB and Gyn practice

Case discussion

What is anemia?

Sign?

Clinical finding?

Laboratory finding?

Disease?

Pointer to a systemic disease?

The first step in any diagnosis:

physical examination

determining its cause

A detailed medical, personal, and dietary history :

Any family or personal history of anemia

A history jaundice, or enlarged spleen

Heavy menstrual bleeding in women

Any signs of internal bleeding.

Of all the diagnostic tests available, complete blood count is one of the

single most valuable tools in assessing the general health of the body.

Provides a snap shot of the hematopoietic system at a specific point in

time.

It is a valuable indicator of disease, either local or systemic

Complete Blood Count (CBC)

a panel of tests that measures RBC,WBC and platelets.

For diagnosis of anemia, the CBC provides critical information on:

the size, volume, and shape of RBC

Hemoglobin

Anemia is when Hb is

< 11 g/dL for pregnant women

< 12 g/dL for non-pregnant women

CBC

The CBC includes

quantitative evaluation of erythrocytes, leukocytes and

platelets and

Qualitative - microscopic examination of the blood film to

detect morphological abnormalities that provide valuable

insight to various disease conditions.

Components of CBC

RBC parameters

Platelet parameters

WBC parameters - Scattergram

Reticulocyte count

Parameters…

RBC parameters RBC count

Hemoglobin

Hematocrit

MCV

MCH

MCHC

RDW

Reticulocyte

Nucleated RBC

WBC parameters

WBC count

Differential

Platelet parameters

Platelet count

MPV

PDW

PCT

All the routine tests have been automated and new tests

have been developed.

Currently available automated analysers make it possible to

process several hundreds of blood specimens a day.

All automated hematology analyzers in addition to

enumerating the CBC results generate:

red cell histograms

platelet histograms and

white cell histograms or scattergrams

The RBC and platelet histograms depict the cell sizing data

in graphic form by plotting relative cell number versus size

(volume)

whereas scattergrams are two- dimensional or three-

dimensional plots of multiparameter data obtained for the

DLC.

Red cell Indices

mean cell volume (MCV)

mean corpuscular hemoglobin (MCH)

and mean cell hemoglobin concentration (MCHC)

help us to classify an anemia as:

regenerative (blood loss or hemolysis) or

nonregenerative (production defect)

often giving us insight to the etiology

25-75 fl 200-250 fl

Erythrocyte (RBC) Histogram

RBC size: 80-95 fl

RBC detection: between 25 and 250 fl

Distribution curves are separated by flexible

discriminators: RL & RU

RL RU

RBCPLT

MCV

MCV (mean corpuscular volume)

The average volume of RBC

Hct

= 10 (fl)

RBC count (m/µL)

e.g. Hct= 40%

RBC=5.0 (m /µL)

MCV= 40/5.0 10 = 80 fl

NR= 80-96 fl

MCH

MCH (mean corpuscular hemoglobin)

The average content of Hb in average RBC.

It is directly proportional to the amount of Hb and RBC size.

Hb

RBC count (m/µL)

10 (pg)MCH =

e.g. Hb = 14 g/dl

RBC = 4 (m/µL)

MCH= 14/4 10

= 35 pg

NR= 27-32 pg

MCHC

MCHC (mean corpuscular hemoglobin concentration)

Express the average concentration of hemoglobin per unit volume of

RBC.

It defined as the ratio of the weight of hemoglobin to volume of RBC.

Hb (g/dl)

Hct (%)

100 (%)MCHC=

e.g. Hb = 14 g/dl

Hct = 45 %

MCHC 14/45 100 = 31%

NR= 32-36%

RDW and HDW

The new additions to the CBC profile which have

useful clinical application.

Red cell distribution width (RDW) – an indicator of the

degree of anisocytosis

Hemoglobin distribution width ( HDW) - is a red cell

parameter that measures anisochromia which along with MCV and

RDW are useful in the differential diagnosis of microcytic anemia.

RDW

RDW - coefficient of variation of the red blood cell

distribution histogram.

Quantitative measure of variation in RBC size

(anisocytosis)

RDW is elevated in:

iron deficiency anemia

RDW is normal in microcytic anemia of thalassemia.

RBC - Histogram Distribution Width

Reference range less than 16 %

200 250 fl

100 %

RDW – CV is equivalent to

68,26 % of the distribution curve

RDW-CV

RDW – SD standerd devation at 20 %

of the distrubution curve

Reference range: 37 - 46 fl200 250 fl

100%

RDW-SD

.

20%

68.26%

Red cell indices in Anemia

Anemia associated with thalassemia minor:

low MCV, a normal RDW, and elevated HDW

Iron deficiency anemia:

Low MCV, an increase in both RDW and HDW

Marrow regeneration as in haemolytic anemias :

elevated MCV, RDW and HDW.

The severity of anemia is categorized by:

Mild anemia Hb 9.5g/dl

Moderate anemia Hb 7.0 - 9.5 g/dL

Severe anemia Hb below 7.0 g/dL

Peripheral smear Reticulocyte smear

Reticulocyte Count

Reticulocyte count is the percent of immature RBCs

Normal levels 0.5 - 2%

Corrected reticulocyte count compares anemic to non-anemic

counterparts to assess response as reticulocyte count may

overestimate response

Corrected Reticulocyte Count = % Retic X HCT/45

Reticulocyte Correction Factor

RPI = % reticulocytes X HCT/45 X 1/Correction Factor

Normal RPI =1

RPI < 2 Hypoproliferative anemia

RPI greater than/equal 2 Hyperproliferative Disorder

Hematocrit Correction Factor

40-45 1

35-39 1.5

25-34 2

15-24 2.5

CLASSIFICATION OF ANEMIAS

Anemias may also be classified functionally into:

Hypoproliferative (when there is a proliferation defect)

Ineffective (when there is a maturation defect)

Hemolytic (when there is a survival defect)

FUNCTIONAL CLASSIFICATION OF ANEMIAS

Kinetic Approach

Decreased RBC production

Lack of nutrients (B12, folate, iron)

Bone Marrow Suppression

Increased RBC destruction

Inherited and Acquired Hemolytic Anemias

Blood Loss

Morphological Approach

Microcytic (MCV < 80)

Reduced iron availability

Reduced heme synthesis

Reduced globin production

Normocytic ( 80 < MCV < 100)

Macrocytic (MCV > 100)

Liver disease, B12, folate

MORPHOLOGICAL CLASSIFICATION OF

ANEMIAS

NORMOCYTIC NORMOCHROMIC ANEMIAS

MICROCYTIC HYPOCHROMIC ANEMIAS

MACROCYTIC ANEMIAS

Case 1

A 72 year old

lady has the

CBC findings

shown..

Case 1

What test would you order for this

patient?

A-Hemoglobin Electrophoresis

B-Retic count

C-Stool for occult blood

D-B12 Assay

E-Bone marrow biopsy

Peripheral Blood smear:

RBCs are hypochromic & microcytic

Case 1

Two questions:

What is your diagnosis?

What is the next step for this patient?

Case 1

Answers

Question 1

Likely Iron Deficiency Anemia

Question 2

Colonoscopy

Iron Deficiency Anemia: Peripheral Smear

Microcytosis &, Hypochromic RBCs

Iron Deficiency Anemia

Low Retic Count

High RDW

Low iron level

High TIBC

Low ferritin

Degrees of Iron Deficiency

Tests for Assessing Iron Status

Serum iron

Total iron binding capacity (TIBC)

Transferrin saturation = serum iron/TIBC x 100

Serum ferritin

Serum transferrin receptor (sTfR)/serum ferritin

[R/F ratio]

Reticulocyte haemoglobin content

Stainable iron in bone marrow

Case 2

A 28 year old lady G2P1

16 weeks gestation has

become progressively more

fatigued at the end of the day.

This has been going on for

months.

In the past month she has noted

paresthesia with numbness in the

feet.

A CBC demonstrates the findings

shown.

Case 2

A peripheral blood smear (the slide is representative of this condition) shows red blood cells displaying macro- ovalocytosis and neutrophils with hypersegmentation.

Case 2

Which of the following tests would be most useful to determine the

etiology?

A. Hemoglobin electrophoresis

B. Reticulocyte count

C. Stool for occult blood

D. Vitamin B12 assay

E. Bone marrow biopsy

Case 2

Questions:

• What is the diagnosis from these findings?

• How do you explain the neurologic findings?

Case 2

Answers:

Question 1

This is a macrocytic (megaloblastic) anemia. The neurologic findings

suggest vitamin B12 deficiency (pernicious anemia).

Question 2

The B12 deficiency leads to degeneration in the spinal cord (posterior and

lateral columns).

Case 3

24 year old lady presented at 34 weeks of gestation with headache, vomiting and epigastric pain of acute onset. On examination she had anemia and jaundice.

Investigations

Hb 5.6g/dl

TC 22000/cmm

DC N 86 L 5 Bd 3 Myelo 2 meta 4 NRBC 7/100 WBC

Platelet count 40.000/cmm

Case 3

Peripheral smear:

Case 3

Biochemical investigations:

Serum bilirubin 2 .5 mg

Conjugated 0.8

AST 786 IU/L ALT 1030 IU/L

Alkaline phosphatase: 240

PT 13 sec C 12 sec INR 1

Case 3

HELLP syndrome

Acute fatty liver of pregnancy

1- Abnormalities of RBC interior

a. Enzyme defects

b. Hemoglobinopathies & Thalassemia M

2-RBC membrane abnormalities

a. Hereditary spherocytosis, elliptocytosis etc

b. Paroxysmal nocturnal hemoglobinuria

c. Spur cell anemia

3- Extrinsic factors

a. Hypersplenism

b. Antibody : immune hemolysis

c. Traumatic & Microangiopathic hemolysis

d. Infections , toxins , etc

Hereditary

Acquired

A Very Simple Classification of Hemolytic Anemias

Laboratory Evaluation of Hemolysis

Extravascular Intravascular

HEMATOLOGIC

Routine blood film

Reticulocyte count

Bone marrow

examination

Polychromatophilia

Erythroid

hyperplasia

Polychromatophilia

Erythroid

hyperplasia

PLASMA OR SERUM

Bilirubin

Haptoglobin

Plasma hemoglobin

Lactate dehydrogenase

Unconjugated

, Absent

N/

(Variable)

Unconjugated

Absent

(Variable)

URINE

Bilirubin

Hemosiderin

Hemoglobin

0

0

0

0

+

+ severe cases

Acute Myeloblastic Leukemia Aplastic anemia

A logical stepwise approach in the context of clinical presentation

selection of appropriate laboratory tests to support the clinical

suspicion

Arrive at the correct diagnosis