What does baso regarding bloodwork mean?

I assume you are....: Referring to basophils, a subtype of granulocytes (a kind of white blood cell) that has a distinct appearance in a blood smear. They are basophilic, which means they stain dark purple with hematoxylin. They are rich in histamine, Heparin and chondroitin sulfate). They are often difficult to detect because they are rare. When elevated, this is usually associated with eosinophilia & atopic response.