Monoclonal peak on electrophoresis (monoclonal gammopathy, MGUS)

• No further tests in the community before the opinion: haematologist quickly.
• Bone pain, deterioration in general condition, lymphadenopathy, anaemia, hypercalcaemia, renal failure, bone lesions, hyperviscosity.

Laboratory tests

• FBC
• Serum calcium (to be corrected for albumin or for total protein from the electrophoresis)
• Serum albumin (to interpret serum calcium)
• Serum creatinine with eGFR
• Urine protein:creatinine ratio (spot sample)
• Serum protein immunofixation (if the peak has not yet been typed)if neededPeak seen on electrophoresis but not characterised: the laboratory normally types it on its own initiative; unnecessary if the isotype is known ^[2,7].
• Urine protein electrophoresis (on the same sample as the urine protein:creatinine ratio)
• Serum immunoglobulins (IgG, IgA, IgM) (if recurrent infections)if neededRecurrent bacterial infections: looking for a fall in residual polyclonal immunoglobulins, the only use of this test according to the HAS; it does not measure the peak ^[2].
• Serum free light chains kappa and lambda, with ratioif neededTo complete the Mayo Clinic risk score ^[8]; specialist prescription according to the HAS, not reimbursed in primary care in France ^[2,9].
• NT-proBNP (at the slightest doubt of cardiac involvement)if neededSuspected cardiac involvement suggesting AL amyloidosis (dyspnoea, lower-limb oedema): NT-proBNP indicated according to the IFM (French Myeloma Intergroup) ^[3].

Laboratory tests

• FBC
• LDH
• Serum creatinine with eGFR
• Urine protein:creatinine ratio (spot sample)
• Urine protein electrophoresis (on the same sample as the urine protein:creatinine ratio)
• Serum calciumif neededThe IFM (2024) asks for serum calcium and albumin in any peak, without distinguishing the isotype ^[3]; the HAS asks for LDH and not calcium for an IgM peak ^[2].
• Serum albumin (IFM list, not requested by the HAS for an IgM peak)if neededThe IFM (2024) asks for serum calcium and albumin in any peak, without distinguishing the isotype ^[3]; the HAS asks for LDH and not calcium for an IgM peak ^[2].

At 6 months, then every year (same laboratory)

• Serum protein electrophoresis
• FBC
• Serum creatinine with eGFR
• Urine protein:creatinine ratio (spot sample)
• Serum calcium (IgG or IgA peak)if neededIgG or IgA peak: risk of progression to myeloma ^[2].
• LDH (IgM peak)if neededIgM peak: risk of progression mainly to Waldenström disease ^[2].
• Serum albumin (with serum calcium)if neededIFM monitoring list, which combines serum albumin and calcium ^[3]; useful for interpreting the serum calcium of an IgG or IgA peak ^[2].