What is your approach to evaluating a patient with known rheumatologic disease and elevated free kappa:lambda ratio, but no evidence of monoclonal immunoglobulins?

The information given is a bit sketchy. But assuming a bone marrow biopsy has been done and there is no evidence of malignancy, I would adopt a watch-and-wait approach. If no bone marrow has been done, I would keep an eye on the appropriate blood tests and in collaboration with a hematologist do a b...