Bill Cook, who has been looking after these assays in this dept, for many
years says:-
Routine e/p of known paraproteinaemia will be used to measure paraprotein
and the value is reported. For GPs the fact that it is stable, increased or
decreased will be noted and attention drawn to increasing values.
Quantitation done by densitometry (SEBIA Preference densitometer)
Generally paraprotein concentrations of 5 g/L or less for IgG paraprotein
are usually, but not always, benign. Concentrations between 5 and 10 g/L
are suspicious. If 3 month repeat shows increasing paraproteinaemia,
results suggest smouldering myeloma.
Concentrations between 10 and 20 g/L are usually associated with
malignancies and usually show symptoms. Concentrations of over 20 g/L are
generally malignant.
With IgA and IgM the values need only be slightly raised above normal limits
to indicate malignancy. IgM myeloma is rare and IgM paraproteins are
generally indicative of Waldenstroms macroglobulinaemia.
Laboratoires. SEBIA - France publish a small book called "Serum protein,
electrophoresis and immunofixation" which is useful. Also "The Binding
Site" Birmingham, UK has an excellent small book on paraproteins, including
measurements and significances.
Hope this is useful.
Elliott Simpson
Consultant Clinical Scientist
Clinical Director, Labs & Pharmacy
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