Is a low sodium the same as a low white blood count?

No. While "Table Salt" is white, the amount of sodium Na+ in your blood has nothing to do with WBC in your plasma. White Blood Cells (WBC) are immune cells that fight infection in the body.

They are not the same thing, but can be linked since low sodium in the plasma can be associated with renal tubule dysfunction, and an immunological disease could have allowed a pathogen to enter the kidneys and destroy them. If you're curious about these levels you've already spoken to a physician because you seem to have the blood work done already, ask your physician.