It means your number of red blood cells(RBC) or the amount of haemoglobin (oxygen-carrying protein) in red blood cells is decreased.
Anemia is a medical condition in which the red blood cell count or hemoglobin is less than normal. The normal level of hemoglobin is generally different in males and females. For men, anemia is typically defined as hemoglobin level of less than 13.5 gram/100 ml and in women as hemoglobin of less than 12.0 gram/100 ml. These definitions may vary slightly depending on the source and the laboratory reference used.
What causes anemia?
Any process that can disrupt the normal life span of a red blood cell may cause anemia. Normal life span of a red blood cell is typically around 120 days. Red blood cells are made in the bone marrow.
Anemia is caused essentially through two basic pathways. Anemia is caused by either:
a decrease in production of red blood cells or hemoglobin, or
an increase in loss or destruction of red blood cells.
A more common classification of anemia (low hemoglobin) is based on the Mean Corposcular Volume (MCV) which signifies the average volume of individual red blood cells.
If the MCV is low (less than 80), the anemia is categorized as microcytic anemia (low cell volume).
If the MCV is in the normal range (80-100), it is called a normocytic anemia (normal cell volume).
If the MCV is high, then it is called a macrocytic anemia (large cell volume).
Looking at each of the components of a complete blood count (CBC), especially the MCV, a physician can gather clues as to what could be the most common reason for anemia in each patient.