Haematology
Overview of Haematology
- Haematology is the branch of medicine that focuses on the study of blood, blood-forming organs, and diseases related to blood.
- It involves the study of various blood components like red blood cells, white blood cells, platelets, the haemoglobin, blood proteins, bone marrow, and blood diseases.
Haematological Tests
- Commonly performed haematology tests include complete blood count (CBC), coagulation tests like prothrombin time (PT), and activated partial thromboplastin time (aPTT).
- Blood smear is a simple and effective test used to view and identify blood cells.
- Blood culture tests are conducted to identify bacteria or fungi in the blood.
Equipment Used for Haematology Testing
- Automated cell counters are most commonly used to perform CBC.
- Microscopes are used for microscopic examination of blood smears.
- Flow cytometers may be employed for more sophisticated analysis, such as identifying specific cell populations.
- Coagulometers measure the ability of blood to form a clot.
Units of Measurement in Haematology
- The concentration of red blood cells or haemoglobin is generally expressed as grams per decilitre (g/dL).
- Counts of cells, such as white blood cells or platelets, are commonly expressed in cells per microlitre (cells/µL).
- Blood clotting time is generally noted in seconds.
Interpreting Haematology Test Results
- Results are compared with established normal ranges which correspond to healthy individuals.
- Variations from the norm might indicate diseases like anaemia, infections, autoimmune diseases, cancers, and bleeding disorders.
- False positives and negatives can occur. For example, dehydration might produce a false positive for polycythaemia (an excess of red blood cells).
- Haematology results are best interpreted in context of patient’s symptoms, medical history, and results from other diagnostic tests.
- Understanding interdependencies and correlations between different haematological measurements is crucial in interpreting test results.