Finding the right tests…
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Finding the right tests…
Haematology
A differential leucocyte count breaks your total white cell count into its five component types - neutrophils, lymphocytes, monocytes, eosinophils and basophils - and reports each as a percentage. A lab technician spreads a drop of blood thinly on a glass slide, stains it, and either counts cells under a microscope or runs the sample through an automated analyser. Because each white cell type responds to a different kind of threat, seeing which ones are raised or lowered helps narrow down a bacterial infection from a viral one, an allergic reaction, or something affecting the bone marrow itself. It is usually ordered alongside a full blood count rather than on its own.
Results are reported as percentages of total white cells - typically neutrophils 40 to 60 percent, lymphocytes 20 to 40 percent, monocytes 2 to 8 percent, eosinophils 1 to 4 percent and basophils 0.5 to 1 percent - plus a check for immature or abnormal cells that should not normally appear in circulating blood. The same blood draw used for a full blood count is used here; no separate sample is usually needed. A pathologist reviews the slide directly when the automated count flags something unusual.
A raised total white cell count on its own does not say much. Knowing which type is raised does: more neutrophils usually points toward a bacterial infection, more lymphocytes toward a viral one, and more eosinophils toward an allergic or parasitic cause. Each cell type is read against the others, not in isolation.
Automated counters sort normal cells quickly, but they flag a slide for manual review when they see something unusual - cells that look immature, oddly shaped, or a type that should not be in circulating blood at all. A trained eye at the microscope then confirms what the machine suggested.
- Investigating a fever or suspected infection - Following up an abnormal total white cell count - Monitoring known blood disorders or ongoing chemotherapy - Checking for allergic or parasitic causes of symptoms
A single differential count is a snapshot. Your doctor usually reads it alongside your symptoms, your history and, if needed, a repeat test a few days later. Ask your doctor or the centre if you're unsure what your own result means.
Typical adult ranges are roughly neutrophils 40 to 60 percent, lymphocytes 20 to 40 percent, monocytes 2 to 8 percent, eosinophils 1 to 4 percent and basophils 0.5 to 1 percent. Ranges vary by lab, so check your own report's reference values.
No. A complete blood count measures overall cell numbers like red cells, white cells and platelets. DLC is the breakdown of white cells into their five types, and is often ordered as part of the same blood draw.
There is no fixed rule for DLC alone. Ask your doctor or the centre, especially if other fasting blood tests are being drawn at the same visit.
It gives a strong clue but not a definite answer. More neutrophils usually leans bacterial and more lymphocytes usually leans viral, but your doctor weighs this alongside your symptoms and, sometimes, further tests.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
Immature white cells appearing in blood can be a normal response to a severe infection or a sign of a bone marrow disorder that needs further investigation. This finding usually prompts your doctor to review the slide personally.
DLC reports the percentage breakdown of white cell types. GBP, or General Blood Picture, is a broader look at all three cell lines - red cells, white cells and platelets - for shape and appearance, not just white cell percentages.