Can gastritis cause high (2900) calprotectin? i have had cd and uc ruled out with colonoscopy?

Gastritis probably can raise calprotectin, but probably not to such a high level. As in previous answer, you may need to be checked for inflammatory bowel disease involving the small intestine, since the colon isn't involved. Work with your doctor(s); there is no possibility of conclusive answers on this forum. No point in asking about every other condition that comes to mind. Good luck.