What is this test?
A professional counts and examines the main white-cell types under a microscope. Manual review can add detail when automated counts are flagged or unusual cells are suspected.
Why might it be ordered?
- To clarify an abnormal or flagged automated white-cell result.
- To assess white-cell patterns during infection, inflammation or a suspected blood disorder.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Fasting is usually unnecessary. Tell your clinician about recent infection, steroid treatment and other medicines that can change white-cell counts.
How should you understand the result?
Percentages should be considered with absolute cell counts and the total white-cell count. A pattern can suggest next steps but rarely establishes the cause alone.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.