I just had blood work done and i was wondering what it means when you plt is high?

Thrombocytosis: Means your platelet count is above the normal range. Etiology varies from iron deficiency anemia, essential thrombocytosis, polycythemia Vera and myeloid malignancies

Blood tests: There are a few diseases that leap out from blood tests. Most of the time, however, blood tests don't tell the doctor much on their own. Platelet counts rise and fall frequently and a single high platelet count is unlikely to be of consequence.

Depends: This often depends on how high you mean. The platelet count can double as a nonspecific indicator of stress, when internal stress hormones push platelets off the walls of blood vessels into the circulation. It would be expected to settle down after the stress subsides. There are isolated conditions where it is very high or very low, but that is easy to spot.