What is the role of lab tests in the workup of light-chain deposition disease (LCDD)?

Updated: Sep 26, 2019
  • Author: Swapna Boppana, MD; Chief Editor: Emmanuel C Besa, MD  more...
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The laboratory workup for light-chain deposition disease (LCDD) includes the following:

  • Routine serum chemistries to evaluate hepatic and renal function

  • Complete blood cell (CBC) count to assess for anemia

  • Serum and urine electrophoresis with immunofixation to evaluate for the presence of a monoclonal protein

  • Repeated studies of serum and urine protein immunoelectrophoresis (PEL) with immunofixation (IFE), to demonstrate the presence of monoclonal protein

  • In a minority of patients, a monoclonal protein may never be found in either serum or urine

  • Quantitative serum assays for immunoglobulin free light chains: The recent introduction of this test has increased the sensitivity of laboratory tests to identify monoclonal gammopathies. [33, 34]

The most recent diagnostic screening recommendations are serum PEL with IFE and quantitative serum assays for free light chains. [35] It is also recommended that urine PEL and IFE should be included when screening for amyloid light-chain (AL)–amyloidosis or LCDD. [13, 33] When all three are combined, the sensitivity for LCDD is 83%, but decreases to 77.8% when urine PEL with IFE is omitted. Excluding the quantitative serum assays for free light chains also decreased the sensitivity for detection of LCDD.

Sometimes these tests can still miss the presence of a monoclonal protein, thus kidney biopsy is needed for adequate and timely diagnosis. [11, 36] Tissue should be sent for immunohistologic analysis for confirmation; it is noncongophilic in nature. Light-chain restriction analyses confirm the presence of monoclonal light or heavy chain.

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