1. Erythrocyte Sedimentation
Rate (ESR)
Definition:
- ESR is the
rate at which red blood cells (RBCs) settle down in a vertical tube
in one hour.
- It is a nonspecific
test used to detect inflammation.
Normal Values:
|
Gender |
ESR (Westergren method) |
|
Male |
0–15 mm/hr |
|
Female |
0–20 mm/hr |
Factors Affecting ESR:
|
Increases ESR |
Decreases ESR |
|
Infections |
Polycythemia (↑ RBCs) |
|
Anemia |
Sickle cell anemia (abnormal RBC shape) |
|
Pregnancy |
Congestive heart failure |
|
Tuberculosis, cancer |
Mnemonic for ↑ESR: "TIPA"
T – TB
I – Infections
P – Pregnancy
A – Anemia
Clinical Uses of ESR:
- Detect inflammation
or infection
- Monitor chronic
diseases (e.g., TB, autoimmune disease)
- Helpful in
diagnosis + prognosis
2. Packed Cell Volume
(PCV) / Hematocrit
Definition:
- PCV is the
percentage of RBCs in total blood volume.
- Measured
after centrifugation.
Normal Values:
|
Gender |
PCV (%) |
|
Male |
40–54% |
|
Female |
36–46% |
Clinical Importance:
- ↑ PCV → Dehydration,
polycythemia
- ↓ PCV → Anemia,
overhydration
Mnemonic: “PVC in Blood = Percentage Volume of Cells”
3. Blood Indices
Blood indices help understand the size, color & content of
RBCs.
There are 3 main indices:
A. MCV – Mean
Corpuscular Volume
- Shows the
average size of RBC
- Unit: fL
(femtoliters)
Formula:
MCV = (PCV × 10) / RBC count (in millions/μL)
Normal: 80–96 fL
|
Value |
Meaning |
|
< 80 fL |
Microcytic (small) |
|
80–96 fL |
Normocytic (normal) |
|
> 96 fL |
Macrocytic (large) |
Mnemonic: "MCV = Micro, Normal, Macro"
B. MCH – Mean
Corpuscular Hemoglobin
- Amount of
Hb in each RBC
Formula:
MCH = (Hb × 10) / RBC count
Normal: 27–32 pg
|
Value |
Meaning |
|
↓ MCH |
Hypochromic (less color) |
|
Normal MCH |
Normochromic |
Mnemonic: “MCH = Mean Color of Hemoglobin”
C. MCHC – Mean
Corpuscular Hemoglobin Concentration
- Concentration
of Hb in RBCs
Formula:
MCHC = (Hb × 100) / PCV
Normal: 32–36%
|
Value |
Meaning |
|
↓ MCHC |
Hypochromic anemia |
|
↑ MCHC |
Hereditary spherocytosis |
Mnemonic: “MCHC = Hb Concentration”
Summary Table:
|
Index |
Full Form |
Normal Value |
Indicates |
|
MCV |
Mean Corpuscular Volume |
80–96 fL |
RBC size |
|
MCH |
Mean Corpuscular Hb |
27–32 pg |
Hb content per RBC |
|
MCHC |
Mean Corpuscular Hb Conc. |
32–36% |
Hb concentration in RBC |
Super Mnemonic for Blood Indices:
“VCC = Volume, Content, Concentration”
- V – MCV
(volume)
- C – MCH
(content)
- C – MCHC
(concentration)
FAQs – Frequently Asked Questions
Q1. What is ESR and
what does it indicate?
Ans: ESR is the rate of settling of RBCs in 1 hour.
↑ ESR indicates inflammation, infection, anemia, or chronic disease.
Q2. What is normal PCV?
Ans:
- Males: 40–54%
- Females: 36–46%
Q3. What does a low MCV
mean?
Ans: Microcytic anemia – small-sized RBCs, usually due to iron deficiency.
Q4. What is the use of
MCHC?
Ans: Tells us about Hb concentration in RBCs, useful in diagnosing hypochromic anemias.
Q5. Why is ESR
increased in pregnancy?
Ans: Due to increased fibrinogen & globulins, which promote faster RBC
stacking (rouleaux formation).
