Practice Cases in primary care laboratory medicine

Paraprotein management

BMJ 2006; 333 doi: https://doi.org/10.1136/bmj.333.7560.185 (Published 20 July 2006) Cite this as: BMJ 2006;333:185
  1. W Stuart A Smellie ([email protected]), consultant chemical pathologist1,
  2. Gavin P Spickett, consultant clinical immunologist2
  1. 1 Clinical Laboratory, General Hospital, Bishop Auckland DL14 6AD,
  2. 2 Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP
  1. Correspondence to: WSA Smellie
  • Accepted 1 June 2006

This article explores best practice in the investigation and monitoring of paraprotein bands in blood or urine. It looks at the pitfalls and provides a summary of guidance

We present two cases illustrating the use of electrophoresis in the diagnosis and monitoring of plasma cell dyscrasias. The presence of monoclonal protein bands (paraproteins) in myeloma is well recognised; other conditions in which paraproteins may be seen are less well understood, as is the relatively common monoclonal gammopathy of unknown significance (MGUS) often previously referred to as benign paraproteinaemia.

Case 1

A 58 year old woman was referred urgently to hospital with a three month history of lethargy, weight loss, dysphagia, and nausea. On the day she was seen by her general practitioner she was weak and hypotensive (90/58 mm Hg). Examination showed an underweight woman (body mass index 19) with a blood pressure of 90/60 mm Hg, pulse 90 beats per minute, muscle wasting, no oedema, and no focal neurological signs.

Results of initial laboratory investigations were sodium 128 mmol/l, potassium 5.2 mmol/l, urea 7.2 mmol/l, creatinine 105 µmol/l, total protein 52 g/l, albumin 27 g/l, aspartate transaminase 68 IU/l, alanine transaminase 86 IU/l. Serum immunoglobulins IgG, IgA, and IgM were within the reference range.

A short synacthen test produced blood cortisol concentrations of 254 mmol/l at 0 minutes and 316 mmol/l at 30 minutes. She was given replacement steroids and began to improve.

Investigation of her low serum albumin showed proteinuria (total protein excretion 8.2 g/24 hours). Serum electrophoresis showed no visible paraprotein band, and a subsequent immunofixation was negative. Urine electrophoresis showed a dense albumin band and one additional band, typed by immunofixation as kappa light chains (600 mg/l).

She was referred for nephrology assessment. Serum amyloid component P (SAP) scintigraphy showed heavy amyloid load in spleen and liver. In …

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