Immunoglobulin M (IgM) Heavy and Light Chain (HLC) Pairs, ? and ? With Ratio

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CPT Code:


Test Type: 0.75 mL Serum
Stability Time:



Room temperature

7 days


7 days


7 days

Freeze/thaw cycles

Stable x2

Reference Range:

• IgM κ (g/L): 0.29−1.82

• IgM λ (g/L): 0.17−0.94

• IgM κ:IgM λ ratio: 0.96−2.30

An elevated IgM heavy and light chain (HLC) pair ratio suggests a clonal proliferation of an IgM κ clone of plasma cells.

A low IgM HLC pair ratio suggests a clonal proliferation of an IgM λ clone of plasma cells.


For the quantitative measurement of human IgM heavy chain and light chain intact immunoglobulin in serum. The test result is to be used with previously diagnosed Waldenström's macroglobulinemia in conjunction with other clinical and laboratory findings. This assay has not been established for the diagnosis, monitoring, and prognosis of Waldenström's macroglobulinemia.

Heavy and light chain pair quantitation may be useful for:

1. Distinguishing between broadly migrating monoclonal proteins and restricted polyclonal immunoglobulin patterns on serum protein electrophoresis.

2. Quantitating monoclonal IgM proteins that are difficult to quantitate using serum protein electrophoresis alone.

3. Providing a more specific quantitation of the monoclonal protein than total IgM measurements alone.

Decisions on patient evaluation and management must not be given on the basis of IgM κ, IgM λ, or IgM κ:IgM λ ratio measurements alone. Clinical history and other laboratory findings must be taken into account.

Heavy and light chain (HLC) quantitation should be used as a complementary method to serum protein electrophoresis.

The effect of therapeutic drugs on the measurement of IgM κ and IgM λ by this assay has not been evaluated.

Small increases in the concentrations of monoclonal IgM proteins may not result in an altered HLC pair ratio.

Elevated serum concentrations of monoclonal protein are indicative of an underlying abnormality, such as monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma, Waldenström's macroglobulinemia and other lymphoproliferative disorders. Serum protein electrophoresis (SPE) densitometry is recommended to quantify monoclonal proteins.1

Nephelometry can also be used in these instances to measure total IgM, but this will include nontumor immunoglobulin, and measurement of either IgM κ or IgM λ may provide additional information regarding tumor production.

1. Kyle RA, Rajkumar SV. Monoclonal gammopathies of undetermined significance: A review.Immunol Rev. 2003 Aug; 194:112-139. PubMed 12846812

Collection Details:

Patient Preparation:

Patient should be fasting for eight hours to avoid lipemic sample interference.

Collection Instructions:

Red-top tube or gel-barrier tube.

Separate serum immediately after coagulation (30 minutes) to prevent hemolysis.