Abstract
Background: Immunoglobulin monoclonal light chains (MLCs) in serum and urine are markers for monoclonal gammopathy and could serve as markers of minimal residual disease (MRD) in multiple myeloma (MM). Excretion of MLCs in urine is known to result in renal damage and shorter survival in patients with LC-predominant MM. Methods: Retrospective review of urine immunofixation in 1738 specimens at 3 medical centers was conducted to assess the utility of urinalysis for diagnosis and monitoring of monoclonal gammopathy. We tested 228 stored urine specimens via the modified urine immunofixation method, using antisera to assay free LCs (FLCs). Results: Our review of urine immunofixation results and medical records validated the theory that the only meaningful value-Added finding was detection of monoclonal free light chains. Examination of 228 urine specimens using our novel method revealed 18.4% additional positive results. The rate of incremental findings for lambda LCs was nearly 3-fold higher than for kappa LCs. Conclusions: The new method of urine immunofixation is significantly more sensitive and more efficient than the conventional method for detecting MLCs in urine. The new assay appears to be sensitive enough to prove that MLCs serve as a marker of MRD in MM.
Original language | English (US) |
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Pages (from-to) | 527-533 |
Number of pages | 7 |
Journal | Lab Medicine |
Volume | 54 |
Issue number | 5 |
DOIs | |
State | Published - Sep 1 2023 |
Keywords
- free light chain immunofixation
- minimal residual disease
- monoclonal gammopathy
- multiple myeloma
- serum free light chain
- urine immunofixation
ASJC Scopus subject areas
- General Medicine