Which instrument is described as the Standard WBC counting device used to keep track of cells?

• A. Standard WBC counting device
• B. Hemocytometer
• C. Hematocrit tubes
• D. PCV card reader

Answer: (A)

Counting cells with a defined, repeatable volume relies on a specialized counting chamber. The hemocytometer is designed for this purpose, featuring a precise grid ( Neubauer ruling ) and a specific chamber depth that lets you tally cells in a known volume. When doing a manual WBC count, you dilute the blood, load it into the chamber, and count cells in designated grid squares. Using the dilution factor and the chamber’s known volume, you calculate the concentration of cells per microliter. This standardization makes the hemocytometer the go-to instrument for counting blood cells. The other items are used for different measurements: hematocrit tubes determine the packed cell volume after centrifugation, and a PCV card reader reads this volume rather than enumerating cells.