A case of monoclonal gammopathy of undetermined significance with abnormal low levels of plasma glycated albumin by M protein.

Background: It is known that an immunoglobulin abnormality affects various clinical laboratory measurements and leads to abnormal values. We experienced a case of monoclonal gammopathy of undetermined significance (MGUS) showing a falsely low plasma glycated albumin (GA) level.

Case Report: The patient was a 75-y-old male who visited our hospital for thrombocytosis identified during a medical checkup.