What could cause a low platelet, high eosinophil and a high vitamin b12?

Not much: High B12 is never worrisome. Low platelets, especially if below 100,000, need to be addressed with a physician who knows how to do a differential diagnosis and workup. Eosinophils over an absolute count of maybe 1000 should prompt a good history and physical exam and perhaps stool for ova and parasites. Labs are adjuncts to diagnosis and ranges are set to flag a few % of healthies.