What does high protein in blood indicate?

How high and which . Protein? Protein may be elevated if the person is dehydrated. If that is not the case, high protein is usually due to tumors of immunoglobulin producing cells, e.g., multiple myeloma or waldenstrom's macroglobulinemia. These are cancers of the bone marrow or lymph-nodes. Sometimes non-mailgnant, polyclonal increase in immunoglobulins may be high enough to raise the total protein to abnormal level.
Many things. Could be related to an ongoing inflammatory process, such as rheumatoid arthritis. It can also signify a benign process, such as a monoclonal gammopathy of undetermined significance or mgus. It can also suggest a malignant process if the protein is monoclonal; meaning only one protein type, such as igg. Hope this helps.