Use of serum free light chain analysis and urine protein electrophoresis for detection of monoclonal gammopathies.
BACKGROUND
Serum free light chain (FLC) analysis is used in the prognostic assessment and monitoring of patients with monoclonal gammopathies (MG). Its use in detection of MG is less widespread despite good sensitivity for diseases poorly detected by serum protein electrophoresis (SPE), e.g., FLC disease and AL amyloidosis. FLC analysis may facilitate earlier diagnosis in these diseases. However, if replacing urine protein electrophoresis (UPE) in an initial screening algorithm, this must be balanced against any loss of detection of Bence Jones proteinuria (BJP).


METHODS
We assessed the effect of replacing UPE with FLC. Sensitivity of FLC for BJP was assessed in 126 clinical cases where UPE and FLC analyses were performed. Impact on disease detection was assessed from 753 patient sera tested by SPE and FLC and 128 patients matched associated urine samples.


RESULTS
Sensitivity of FLC for BJP was 98%. Use of FLC in routine testing increased the number of MG detected by 7%.


CONCLUSIONS
Using FLC alongside or in place of UPE can give clinical benefit through earlier diagnosis and hence treatment earlier in the patients' disease.
Department of Immunology, Hull Royal Infirmary, Hull, UK. steve.holding@hey.nhs.uk
Stephen
S
Holding
Dorothy
D
Spradbery
Robin
R
Hoole
Rachel
R
Wilmot
Michael L
ML
Shields
Alison M
AM
Levoguer
Philip C
PC
Doré
D001536:Bence Jones Protein / Q000652:urine*; D015331:Cohort Studies; D004586:Electrophoresis / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000097:blood* / Q000652:urine*; D008297:Male; D010265:Paraproteinemias / Q000097:blood / Q000175:diagnosis / Q000652:urine*; D011507:Proteinuria / Q000652:urine; D012189:Retrospective Studies; D016482:Urinalysis / Q000295:instrumentation / Q000379:methods
D007147:Immunoglobulin Light Chains; D001536:Bence Jones Protein