Can I replace intact immunoglobulin measurements with serum FLC measurement?
In many of the retrospective studies others and we have conducted, the intact immunoglobulin measurements gave no information in addition to that given by serum FLC measurements and in many cases gave less information. However, at initial screening, use of SPE to detect intact immunoglobulin is essential as 5% of patients have normal FLC at presentation. It is probable that, for the purpose of monitoring this group of patients, intact immunoglobulin measurements are necessary. When monitoring a patient for relapse, both SPE and FLC assays are needed to ensure detection of either paraprotein at relapse i.e. intact + FLC relapsing as just intact, or just FLC.
