I had a cbc done last week and platelet count is 501 (501,000). everything else is normal. is this a concern? can oral contraceptives cause this?

Elevated platelets: Platelets are one of the acute phase reactants and can be elevated for a number of reasons. Transient elevations are usually not cause for concern but repeat testing would be wise.

Reactive: Your platelet count is moderately elevated. It is not likely that the contraceptives are causing it. Would recommend repeating your cell counts in 2 weeks and checking your stool for occult blood.