It is performed generally by two methods the Sahli method or the cyanmethemoglobin method:

Normal Values	Hb, g/dl
Men	14 – 18
Women	11.5 – 16.5
Children (up to 1 year)	11.0 – 13.0
Children (10 – 12 years)	11.5 – 14.5
Infants (full term cord blood)	3.5 – 19.5

• Decrease in hemoglobin below the normal range indicates anemia.
• It also drops in pregnancy due to hemodilution.
• An increase is also seen in congenital heart disease due to reduced oxygen supply.
• An increase in hemoglobin in emphysema.
• An increase in hemoglobin in polycythemia.

Normal values:

Adults	4,000 – 10,000/cu mm (ml).
At birth	10,000 – 25,000/cu mm (ml).
1 to 3 years	6,000 – 18,000/cu mm (ml).
4 to 7 years	6,000 – 15,000/cu mm (ml).
8 to 12 years	4,500 – 13,500/cu mm (ml).

If there is an increase in the total WBC count and it is more than 10,000/cu mm (ml), it is known as leucocytosis.

Causes of Leucocytosis
Pathological

• It occurs due to bacterial, viral, protozoal (malaria) or parasitic (filaria, hook worm) infections.
• It is also observed in severe hemorrhage and in leukemia.

Physiological Causes of Leucopenia

• Bacterial infections like typhoid, paratyphoid, tuberculosis etc. reduces the count.
• Viral infections like hepatitis, influenza, and measles also reduce the count.
• Protozoal infections like malaria reduce the count.
• Leukemia does it too.
• Primary bone marrow depression (aplastic anemia).
• Secondary bone marrow depression (due to drugs, radiation etc.).
• Anemia (iron deficiency, megaloblastic etc.)

Platelets are very small in diameter – around 3 mm. They help in clotting of blood. Normal platelet count is 250,000 to 500,000/cu mm (ml) and it is said to be adequate. If it is less than that, it is said to be inadequate.

In various types of anemia and in other diseases such as thalassemia, malaria, kidney failure etc., the mature RBCs show significant changes. Various changed RBCs seen are termed as microcytes, macrocytes, hypochromic, spherocytes, target cells, stomatocytes, anisocytosis, poilkilocytosis, sickle cells, ovalocytes, elliptocytes, acanthocytes, burr cells, siderocytes, basophilic stippling, howell–jolly body, cobot ring, schi stocytes, crescent bodies and creneted cells depending upon their morphology.

PCV (packed cell volume) is the amount of packed red blood cells after centrifugation. It is expressed in the percentage of total blood volume.
Normal values
Male: 42–52%.
Female: 36–48%.
Late pregnancy: 23–37%.
Increase in PCV is due to polycythemia, dehydration, emphysema, and congenital heart disease.
Decrease in PCV is due to different types of anemia, hydremia (excessive fluid in the blood which occurs in pregnancy).

MCV – Mean Cell Volume

• Normal value: 82–92 cu mm.
• Increased MCV indicates macrocytic anemias.
• Decreased MCV indicates microcytic anemias.

MCH – Mean Cell hemoglobin

• Normal value: 27–32 pg (pg = 1 picogram = 10–12 g).
• Increased value indicates macrocytic anemia.
• Decreased value indicates hypochromia.

It is average amount of hemoglobin in the red cell compared to normal.

• Normal color index: 0.85–1.15.
• Increase in the color index indicates megaloblastic anemias.
• Decrease in the color index indicates hypochromic anemia.

Blood parasites cause a number of ailments which are more prevalent in tropical counties. The common diseases caused are malaria, kala azar and sleeping sickness.

Normal Value: 32–36%.

• Increased value indicates spherocytosis.
• Decreased value indicates hypochromic anemias.

Blood Routine – Normal Values

Test	Normal Values
Hemoglobin	Men	13.5–17.5%
	Women	11.5–16.5%
Total WBC Count	Adults: 4000–11000/cu.mm
Differential Count	Neutrophils	40–75%
	Eosinophils	1–6%
	Lymphocytes	20–45%
	Monocytes	2–10%
Basophils	0–1%
ESR: (Westegren): 1 hr	Men	1–10 mm
	Women	5–15 mm
Platelet Count	1.5–4.0 lakhs/cu.mm
Reticulocyte Count	Adults: 0.2–2%
RBC (Erythrocyte) Count	Men	4.5–6.5 million/cu.mm
	Women	3.8–5.8 million/cu.mm
Mean Corpuscular Volume	75–97 fl
Mean Corpuscular Hemoglobin	26–33 pg
Mean Corpuscular Hemoglobin Concentration	32–35%
Haematocrit (PCV)	Men	40–54%
	Women	37–47%

Emphysema
It means stretching of body tissue due to the accumulation of gas or air in the tissue or organ. Pulmonary emphysema is a chronic lung disease in which air sacs of the lungs are stretched until the elastic fibers in them are destroyed.
Polycythemia
It is an excess of red blood cells. It may be temporary due to lack of oxygen in the blood. It may be due to heart disease or continued exposure to high altitudes. Also, if may be due to disorder of the bone marrow.
Myeloid leukemia
It is a kind of blood cancer.
Congenital heart disease
It means any heart disorder that is present at birth. Most common is a hole between two ventricles, either narrowing or the wrong position of the aorta (the main artery), or constriction of valves on the left side of the heart with weakness of the heart muscle.
Aplastic anemia
It is a disease of the bone marrow. It produces deficiency of the red blood cells, white blood cells as well as platelets.