Introduction to Anaemia
- Anaemia is defined as a reduction in the concentration of haemoglobin (Hb) in the blood below the lower limit of the normal range for an individual’s age and sex.
- While haemoglobin is the primary marker, other parameters like red cell counts, haematocrit, and absolute values are also essential for a complete assessment.
Normal Haemoglobin Lower Limits
- The threshold for diagnosing anaemia varies based on the patient’s profile:
Category Lower Limit of Haemoglobin (Hb) Adult Males 13.0 g/dl Adult Females 11.5 g/dl Newborn Infants (at birth) 15.0 g/dl Infants (at 3 months) 9.5 g/dl
Diagnostic Parameters
To accurately determine the type and severity of anaemia, clinicians look beyond just the Hb levels. The following indices provide a deeper look at the health of Red Blood Cells (RBCs):
- Red Cell Count: The total number of RBCs per microliter of blood.
- Haematocrit (PCV): The Packed Cell Volume, representing the percentage of whole blood occupied by red cells.
- Absolute Values (RBC Indices):
- MCV (Mean Cell Volume): Measures the average size of the red cells.
- MCH (Mean Cell Haemoglobin): Measures the average amount of haemoglobin in each red cell.
- MCHC (Mean Cell Haemoglobin Concentration): Measures the average concentration of haemoglobin in a given volume of packed red cells.
- Note for Practice: Always consider the age and physiological state (like pregnancy) of the patient before confirming a diagnosis of anaemia, as “normal” ranges shift significantly.