Test Catalog

Test ID: FHLCA    
Immunoglobulin A (IgA) Heavy and Light Chain (HLC) Pairs, Kappa and Lambda with Ratio

Useful For Suggests clinical disorders or settings where the test may be helpful

For the quantitative measurement of human IgA heavy chain and light chain intact immunoglobulin in serum. The result can be used when monitoring previously diagnosed IgA multiple myeloma patients and is used in conjunction with other clinical and laboratory findings.

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 IgA proteins that are difficult to quantitate using serum protein electrophoresis alone.

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

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Elevated serum concentrations of monoclonal protein are indicative of an underlying abnormality, such as monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma, and other lymphoproliferative disorders. International guidelines recommend serum protein electrophoresis (SPE) densitometry to be performed to quantify monoclonal proteins. However, monoclonal IgA proteins can often be obscured by other proteins in the Beta region of a SPE gel, making quantification inaccurate.

Nephelometry can be used in these instances to measure total IgA, but this will include nontumor immunoglobulin, and measurement of either IgA Kappa or IgA Lambda may give a more accurate representation of tumor production. Furthermore, measurement of both IgA Kappa and IgA Lambda, calculation of the IgA Kappa:IgA Lambda ratio and comparison with values found in normal subjects can give a more sensitive indication of clonality. Use of the IgA Kappa:IgA Lambda ratio will also compensate for any changes in plasma volume.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

IgA Kappa (g/L): 0.48-2.82

IgA Lambda (g/L): 0.36-1.98

IgA Kappa:IgA Lambda ratio: 0.80-2.04

Interpretation Provides information to assist in interpretation of the test results

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

A low IgA HLC pair ratio suggests a clonal proliferation of an IgA Lambda clone of plasma cells.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Decisions on patient evaluation and management must not be given on the basis of IgA Kappa, IgA Lambda, or IgA Kappa:IgG Lambda 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 IgA Kappa and IgA Lambda by this assay has not been evaluated.

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

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Smith A, Wisloff F, Samson D; UK Myeloma Forum; Nordic Myeloma Study Group; British Committee for Standards in Haematology. (2005) Guidelines on the diagnosis and management of multiple myeloma 2005. Br J Haematol. 2006 Feb; 132(4):410-451. PubMed 16412016

2. Bradwell AR, Harding S, Drayson M, Mead G. Novel nephelometric assays give a sensitive measure of residual disease in multiple myeloma (MM). Br J Haematol. 2008; 141(s1):39. Abstract 107.