What is the manual method for WBC count based on?

The manual method for white blood cell (WBC) count traditionally involves using a specific system designed for counting cells in a diluted blood sample. The correct approach includes utilizing a dilution that lyses red blood cells, allowing for accurate counting of white blood cells without interference from the numerous red cells present in a typical blood sample. The unopette system is specifically designed to facilitate this process, as it enables uniform dilutions of blood that result in the lysis of red blood cells while preserving the integrity of the white cells for counting.

In this method, after lysis of the red cells, the remaining white cells can be counted using a microscope and a hemocytometer or an automated method if available. This ensures that the count reflects only the white blood cells, providing an accurate measurement critical for diagnosing various health conditions.

Other methods, such as using a fixed diluent without lysing red cells, would not produce a reliable WBC count since the presence of red cells can significantly interfere with the accuracy of the count. Visual assessment alone is insufficient for precise quantitative analysis because it lacks the standardization and control present in methods specifically designed for counting cells. Relying on automated cell counters represents a different technique entirely, often preferred in modern labs for efficiency