Red blood cell indices. Types of blood indices

Red blood cell indices. Types of blood indices

1. Red Blood Cell Indices

2. Morphological Features of RBCs
Functions of the RBCs
Hematological Indices
Learning Objectives

3. RBC are also known as erythrocytes or red blood corpuscles as it contains
haemoglobin which turns red on binding with oxygen.
It also carries carbon dioxide away from tissues to lungs.
It contains certain antigens on its surface membrane that determine blood
groups and makes basis of whole blood transfusion physiology.
Red Blood Cells

4. Clinical Application :
Since RBC uses glucose constantly from plasma,
whenever blood glucose level is to be tested, the sample is taken in the
fluoride vial
Red Blood Cells

5. Red Blood Cells- Morphology-Size
RBCs are anucleated discs
RBC count : 4-6 million/mm
3
,
Life span - 120 days.
Central pallor is seen due to presence of less haemoglobin
molecule in the centre.
Size – Diameter: 7-7.8 µm,
Thickness at the periphery-2.2 µm and
Centre - 1 µm

6. Shape - Normal biconcave disc
Biconcave shape has many advantages :
1. Flexibility RBCs
2. Greater surface area/volume ratio
Red Blood Cells- Shape

7. RBCs Count-4-6 million/mm
3
Hb content-14-16 gm/dl
O
2
carrying Capacity of blood-1 gm Hb binds
to 1.34 ml of O
2
PCV=45±2 ml/100 ml of blood
Red Blood Cells- Normal values

8. Hematological Indices
Red blood cell indices are blood tests that provide
information about the average volume or size (MCV) and
hemoglobin content (MCH, MCHC) of red blood cell.

9. RED BLOOD CELL INDICES:RED BLOOD CELL INDICES:
1.Mean corpuscular volume(MCV)
2.Mean corpuscular hemoglobin(MCH)
3.Mean corpuscular hemoglobin concentration(MCHC)
4.Red cell distribution width (RDW)

10. Mean Corpuscular Volume(MCV)
Average or mean volume of a single red blood cell
Expressed in femto liter (fl)

11. Calculation
Formula:
MCV = PCV in percentage X 10
RBC count per cmm
Normal range:
80-100 fl

12. Mean Corpuscular
Hemoglobin(MCH)
Average hemoglobin content (weight of Hb) in a
single red blood cell
Expressed in picograms(pg).

13. INCREASED
Macrocytic anaemia
Newborns
DECREASED
Microcytic anaemia

14. Mean Corpuscular Hemoglobin
Concentration(MCHC)
Concentration of haemoglobin in 1 dl or 1 liter of packed red
cells

15. Calculation
Formula:
MCHC = Hb in gm/dl X 100
PCV in %
Normal range: 30 – 35 g/dl

16. INCREASED
Hereditary spherocytosis
DECREASED
Hypochromic anaemia

17. CLINICAL SIGNIFICANCE
A) Macrocytic anaemia:
◦MCV slightly increased upto 150 fl
◦MCH is slightly increased
◦MCHC is normal or diminished
B) Microcytic anaemia:
◦MCV is diminished up to 50 fl or lower
◦MCH is diminished to 15 pg or lower
◦MCHC is diminished to 20% or less
C) Spherocytosis:
◦MCV is diminished
◦MCHC is elevated

18. RED CELL DISTRIBUTION
WIDTH
Measures the degree of variation of red cell size in
a blood sample.
Increased in iron deficiency anaemia
Decreased in beta- thalassemia trait
Normal value: 9.0-14.5

19. Mean corpuscular volume (MCV) is the
average volume of a single rbc.
We need values of:
▪ RBC count ▪ PCV

= PCV X 10 µ³
RBCs
= 80-100 µ³
Mean Corpuscular Volume (MCV)

20. Mean Corpuscular Hemoglobin (MCH)
Mean corpuscular hemoglobin (MCH) is the average amount of
hemoglobin of a single rbc.
We need values of:
▪ RBC count ▪ Hb
= Hb X 10 pg
RBCs
= 27-32 pg

21. Mean Corpuscular Hemoglobin Conc. (MCHC)
Mean corpuscular hemoglobin Concentration (MCHC) is the average
concentration of hemoglobin per unit volume of red blood cells.
We need values of:
▪ PCV ▪ Hb

= Hb X 100 g
PCV
32-36 %

22. ERYTHROCYTE SEDIMENTATION RATE (ESR)
ESR is the measurement of the rate of sedimentation of red cells
in anti-coagulated blood.
Blood is allowed to stand for 1 hr in an open-ended glass tube
mounted vertically on a stand
Length of column of plasma above the red cells is measured in
mm.

23. Anticoagulated blood is drawn up into a tube of standardized
dimensions and left in a vertical position for exactly one hour
By that time, the red cells would have separated and settled
from the plasma.
Upper plasma column is recorded by reading from the scale
on the side of the tube.
Measures the distance that RBCs will fall in a vertical tube
over a given time period
Initial screening tool and also as a follow-up test – monitor
therapy and progression or remission of disease

24. Three definite phases:

•First or Lag Phase (10mins) – red cells form a characteristic
rouleaux pattern (aggregation) and sedimentation is generally
slow. (Pack of coins)
•Decantation Phase (40mins) – The rate accelerates in this phase;
fast settling or sinking of RBCs
•Final Packing Phase (last 10mins) – slows again as red cell
aggregates pile up at the base of the tube. There is slow
sedimentation.

25. FACTORS AFFECTING ESR
1.Plasma factor
2.RBC factor
3.Technical factor

26. PLASMA FACTORS
Increased fibrinogen increases rouleaux formation
thereby increasing ESR
S. haptoglobulin , C - reactive protein & cholesterol
also increases ESR
Albumin and lecithin decreases sedimentation i.e.
decreasing ESR

27. RBC FACTORS
Primarily through changes in number and/or shape
Anemia responsible for increased ESR
◦Microcytes – sediment more slowly
◦Macrocytes – sediment faster

28. Poikilocytosis retards ESR because abnormal shape
hampers rouleaux formation
Anticoagulants – Sodium citrate & EDTA doesnot affect ESR
oxalates & heparin may affect

29. METHODS
Westergren’s method
Wintrobe’s method
Micro - ESR
Automated systems
Zeta sedimentation

30. The method for measuring the ESR recommended
by the International Council for Standardization in
Haematology (ICSH)
Based on that of Westergren, who developed the
test in 1921 for studying patients with pulmonary
tuberculosis.

31. CONVENTIONAL WESTERGREN METHOD
The recommended tube is a straight
glass or rigid transparent plastic tube
30 cm in length
2.55 mm in diameter.
Bore must be uniform
A scale graduated in mm extends
over the lower 20 cm.

32. For the diluent, 3.8 g/dl Trisodium citrate used
Dilution – 1:4
0.25ml trisodium citrate : 1ml blood
Mix the blood sample thoroughly and then draw it up into
the Westergren tube to the 200 mm mark by means of a
rubber teat or a mechanical device

33. Place the tube exactly vertical
and leave undisturbed for
exactly 60 min, free from
vibrations and draughts and
not exposed to direct
sunlight.
Then read to the nearest 1
mm the height of the clear
plasma above the upper limit
of the column of sedimenting
cells.
Westergren pipette filled with blood
and placed vertically on the rubber
cork in the rack

34. ERYTHROCYTE SEDIMENTATION RATE
Average ESR value by Westergren Method:
Male – 3-5mm
Female – 4-7mm

35. PROCEDURE – WINTROBE METHOD
1. Add well mixed double oxalate / EDTA blood to the zero mark of
the Wintrobe tube, using a pipette
Avoid air bubbles
2. Place in vertical position in a rack and let sit for 60 minutes
3. Read and record results in millimeter (distance which the cells
have settled)

36. Average ESR value by Wintrobe’s Method:
◦Males: 0 – 9mm/hr
◦Females: 0 – 20mm/hr
◦Children: 0 – 13mm/hr

37. Increased ESR
•Chronic infections e.g. Tuberculosis
•Extensive/ Chronic inflammation
•Collagen vascular disorders
o Systemic Lupus Erythromatosus
o Rheumatoid asthritis
o Systemic Sclerosis
•Shock
•Active syphilis
•Active infectious infections

38. Decreased ESR
•Newborns
•Congestive heart failure
•Polycythemia
•Marked leukocytosis
•Allergic states
•Sickle cell anemia

39. Ratio of volume of RBCs to that of whole blood
It indicates relative proportion of red cells to plasma
Expressed in percentage.
Also called hematocrit or erythrocyte volume fraction
PACKED CELL VOLUME

40. Methods:
1.Macrohematocrit method (Wintrobe Method)
2.Microhematocrit method
3.Electronic Method

41. WINTROBES METHOD
•Wintrobe’s tube – 110mm long,
internal bore 2.5mm &
a flat inner base.
Graded 0-10 on both sides.

43. Method:
1.Mix the anticoagulant blood sample thoroughly
2.Draw blood in a Pasteur pipette
3.Fill the tube upto 10 mark
4.Centrifuge the sample at 2000-2300 rpm for
30mins
5.Take the reading of the length of the column of
red cells

45. Buffy coat- WBC& PLATELETS.
UPPER MOST LAYER – PLASMA
•Yellowish-Jaundice
•Pink-haemolysis
•Milky-hyperlipidemia

47. PCV
reading

48. PRECAUTIONS
 Use recommended amount of EDTA
 Test done with in 6-8 hours
 Wintrobe tube should be filled from below upwards
so that no air bubble is trapped.

49. INCREASED PCV
Polycythemia
-Newborns, High altitude,
Hypoxia due to lung and
heart diseases.
Congestive Heart failure,
Burns (loss of plasma),
Dehydration, Severe
Exercise, Emotional stress
DECREASED PCV
Anaemia
Pregnancy
(Hemodilution)

50. INCREASED
Megaloblastic anaemia
Chronic alcoholism
Liver disease
newborns
DECREASED
Microcytic hypochromic
anaemia

51. Calculation:
Formula:
MCH = Hb in gm/dl X 10
RBC count per cmm
Normal range: 27 – 32 pg