[Analytical interference caused by monoclonal immunoglobulin M with cryoglobulin effect: a case report].

In biochemistry laboratory, monoclonal immunoglobulins are frequently found. They can lead to analytical interferences which are difficult to anticipate. In this case reports, a monoclonal immunoglobulin M with cryoglobulin effect has been responsible of false result of protein electrophoresis because of the whole precipitation of the monoclonal immunoglobulin. This case report allows us to remember the interferences caused by monoclonal immunoglobulins and that clinicians should be aware of these aspects of paraproteins and contacting the laboratory when encountering unexpected results.