Multiple myeloma in chronic kidney disease. Utility of discretionary screening using serum electrophoresis

The incidence of multiple myeloma (MM) has increased in Scotland over the last 20 years. Approximately 25% of cases present directly to renal services. Serum electrophoresis is commonly included in the diagnostic screening tests performed in patients with chronic kidney disease (CKD). We examined the utility of serum electrophoresis in the population presenting to renal outpatient services in Glasgow.

All new patient attendances at general nephrology clinics in the Glasgow renal units between 1/08/2004 and 31/07/2006, along with clinical data, were retrieved from the electronic patient records. Patients with acute kidney injury were excluded. All serum and urine electrophoresis requests and results for the same period were identified from Biochemistry and Immunology Laboratory Services.

A total of 2,544 new patients attended a renal clinic for the first time in the inception period, of whom 1,608 (63.2%) had serum electrophoresis tested. One patient with MM was identified, but the diagnosis was clinically apparent before the serum electrophoresis result was requested. A further 40 subjects had abnormal serum electrophoresis with mean paraprotein of 8.3 g/l (SD 6.1); none of these patients have subsequently developed MM, and the renal abnormalities are felt to be unrelated. This prevalence of monoclonal gammopathy of uncertain significance in 2.5% of the cohort is consistent with the expected prevalence in the general population.

Our data demonstrate that serum electrophoresis in patients with CKD is not a useful screening test to identify MM.