How do you calculate the absolute lymphocyte count from the given data?

To calculate the absolute lymphocyte count, you utilize a straightforward mathematical process where the percentage of lymphocytes is multiplied by the total white blood cell (WBC) count. This calculation provides the actual number of lymphocytes present in a given volume of blood, typically expressed as cells per microliter (µL).

For example, if the total WBC count is 8000 cells/µL and lymphocytes make up 30% of this total, the absolute lymphocyte count would be calculated as 0.30 (the decimal representation of the percentage) multiplied by 8000 cells/µL, yielding 2400 lymphocytes/µL. This method is essential in clinical diagnostics for assessing immune function, diagnosing conditions such as lymphocytosis or lymphopenia, and making appropriate clinical decisions.

The other options do not provide a valid method to deduce the absolute lymphocyte count. Simply adding, dividing, or subtracting the percentage from the WBC count does not yield a meaningful representation of the lymphocyte population in the blood.