Disclaimer: This article aims to provide an overview of how the various causes of anaemia are classified. It does not go into detailed information of the individual causes of anaemia.
Background Information
Definition
Clinical Features
Red Flags
Aetiology and Classification
The morphological classification (based on ) is the most widely used and is the best way to classify anaemia when learning causes and working through differentials. [Ref]
| Anaemia type | (fl) |
|---|---|
| Microcytic anaemia | <80 |
| Normocytic anaemia | 80-100 |
| Macrocytic anaemia | >100 |
Note that the exact cut-offs may vary depending on the source, and there is no single “correct” value to memorise. Exam questions will most likely provide a normal range (e.g. 76–96 fL). Values below the lower limit of normal should be considered microcytic, values above the upper limit of normal should be considered macrocytic, and values within the normal range should be considered normocytic.