It depends upon whether this is the total wbc or some portion of the wbc's. Well, if you or someone you know has a wbc of 1.6 then I would think that their PCP (Primary care Physician) would have referred that person to a specialist, most likely a hematology oncologist in which a bone marrow biopsy would most likely be performed. There are some diseases and medicaions (such as steroids) that could cause the wbc's to be low however so this would need to be addressed as well. The risk of very low wbc's are infections so it is important to have this checked and treated as soon as possible. Good luck, Susanne