Serum protein electrophoresis and immunoglobulins are used to establish whether a paraprotein is present, which may indicate a plasma cell dyscrasia such as multiple myeloma, Waldenstrom’s macroglobulinaemia, smouldering myeloma, amyloidosis, or monoclonal gammopathy of undetermined significance (MGUS). Monitoring of a paraprotein in primary care may be
appropriate where the patient is deemed to have MGUS.

• When a plasma cell dyscrasia is suspected serum protein electrophoresis, immunoglobulins and urine Bence Jones Protein (BJP) should be requested. At the present time, screening by serum free light chains (SFLC) is not routinely available in Scotland (1,2).
• In patients with MGUS who are being followed up in primary care (3).

In addition to general signs of malignancy such as anaemia and weight loss, clinical features/abnormal results which may prompt investigation for plasma cell dyscrasia include bone pain, especially back pain, or bone fractures, raised ESR or PV, hypercalcaemia, unexplained renal failure, raised total protein, raised individual immunoglobulin or reduction in one or more immunoglobulin class (5).

• A significant paraprotein is unlikely to develop in less than 1 year so there is no need to repeat after a negative result unless symptoms escalate or new symptoms develop (3,4).
• Newly diagnosed MGUS patients with paraprotein <5 g/L or life expectancy <5 years may not require follow up & discontinuation of follow up of established MGUS patients with life expectancy <5 years may be appropriate (3).
• Paraproteins have a significant half-life in the body, so even during treatment for myeloma there is no reason to repeat serum protein electrophoresis at less than 3–4 week intervals.

• Patients with active or smouldering disease will be followed up by Haematologists according to local management protocols.
• Small paraprotein bands <10-15 g/L occur quite commonly in older patients. If there are no significant symptoms of myeloma or other lymphoproliferative disease these may not require treatment. IgG paraproteins <15 g/L & IgA/M paraproteins <10 g/L may bemonitored 3-4 monthly for the first year.5 If patient is clinically stable and paraprotein is stable, follow up 6-12 monthly (3,4).

Please note local management protocols may vary and local guidelines should be followed.

1. Sive J, Cuthill K, Hunter H, Kazmi M, Pratt G, Smith D, et al. Guidelines on the diagnosis, investigation and initial treatment of myeloma: a British Society for Haematology/UK Myeloma Forum Guideline. British Journal of Haematology. 2021;193(2):245–68. Available from: https://onlinelibrary.wiley.com/doi/10.1111/bjh.17410 DOI: 10.1111/bjh.17410
2. National Institute for Health and Care Excellence. Myeloma: diagnosis and management [Internet]. [London]: NICE; 2016 [updated 2018 Oct; cited 2022 Oct 04]. (NICE guideline [NG35]). Available from: https://www.nice.org.uk/guidance/ng35
3. Bird J, Behrens J, Westin J, Turesson I, Drayson M, Beetham R, et al. UK Myeloma Forum (UKMF) and Nordic Myeloma Study Group (NMSG): guidelines for the investigation of newly detected M-proteins and the management of monoclonal gammopathy of undetermined significance (MGUS). British Journal of Haematology. 2009;147(1):22–42. Available from: https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2141.2009.07807.x DOI: 10.1111/j.1365-2141.2009.07807.x
4. Lang T., Croal B. National minimum retesting intervals in pathology [Internet]. 2nd ed. The Royal College of Pathologists; 2021 [cited 2022 Oct 04]. Available from: https://www.rcpath.org/resourceLibrary/g147-minimum-retesting-intervals-in-pathology.html
5. Myeloma Diagnostic Tool: Guidance for Primary Care [Internet]. Myeloma UK; 2020 [cited 2020 Oct 04]. Available from: https://academy.myeloma.org.uk/wp-content/uploads/2020/08/GP-Myeloma-Diagnostic-Tool-MA.pdf