Which option would not affect a manual WBC count?

Which option would not affect a manual WBC count?

• A. Condenser in the farthest "up" position
• B. Objective lens used
• C. Length of time that the hemocytometer has been loaded
• D. Mini clots in the blood

Answer: (B)

Manual WBC counting with a hemocytometer hinges on counting cells within a defined, fixed volume and applying the dilution factor to calculate concentration. The objective lens only changes how large the image appears and how clearly you can see cells; it does not alter the actual volume you’re counting, so as long as you can identify the white blood cells reliably, the magnification used does not change the calculated concentration. What can affect the result are factors that alter the counted volume or the visibility of cells: illumination quality is key, so having the condenser misadjusted can make cells hard to see and lead to counting errors; the time since the chamber was loaded matters because cells can settle, clump, or dry out if you wait too long, skewing results; and any micro clots in the blood will disrupt even distribution and trap cells, producing inaccurate counts.

Manual WBC counting with a hemocytometer hinges on counting cells within a defined, fixed volume and applying the dilution factor to calculate concentration. The objective lens only changes how large the image appears and how clearly you can see cells; it does not alter the actual volume you’re counting, so as long as you can identify the white blood cells reliably, the magnification used does not change the calculated concentration. What can affect the result are factors that alter the counted volume or the visibility of cells: illumination quality is key, so having the condenser misadjusted can make cells hard to see and lead to counting errors; the time since the chamber was loaded matters because cells can settle, clump, or dry out if you wait too long, skewing results; and any micro clots in the blood will disrupt even distribution and trap cells, producing inaccurate counts.