Test Details
Methodology
Turbidimetric
Result Turnaround Time
4 - 6 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
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.
Limitations
Decisions on patient evaluation and management must not be given on the basis of IgA κ, IgA λ, or IgA κ:IgG 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 IgA κ and IgA λ 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.
For initial detection of monoclonal proteins, see:
• Immunofixation (IFE), Serum and Protein Electrophoresis, Serum [001495]
• Immunofixation (IFE) and Protein Electrophoresis, 24-Hour Urine [003467]
Custom Additional Information
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 guidelines1 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 β 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 κ or IgA λ may give a more accurate representation of tumor production. Furthermore, measurement of both IgA κ and IgA λ, calculation of the IgA κ:IgA λ ratio and comparison with values found in normal subjects can give a more sensitive indication of clonality.2 Use of the IgA κ:IgA λ ratio will also compensate for any changes in plasma volume.
Specimen Requirements
Specimen
Serum
Volume
0.75 mL
Minimum Volume
0.5 mL
Container
Red-top tube or gel-barrier tube
Collection Instructions
Separate serum immediately after coagulation (30 minutes) to prevent hemolysis.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
• IgA κ (g/L): 0.48−2.82
• IgA λ (g/L): 0.36−1.98
• IgA κ:IgA λ ratio: 0.80−2.04
An elevated IgA heavy and light chain (HLC) pair ratio suggests a clonal proliferation of an IgA κ clone of plasma cells.
A low IgA HLC pair ratio suggests a clonal proliferation of an IgA λ clone of plasma cells.
Storage Instructions
Refrigerate.
Causes for Rejection
Microbially-contaminated specimen; specimen containing particulate matter; lipemic or hemolyzed specimen
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 123540 | IgA Heavy Light Chains(HLC), S | 123531 | IgA Kappa, S | g/L | 74864-0 | |
| 123540 | IgA Heavy Light Chains(HLC), S | 123532 | IgA Lambda, S | g/L | 74865-7 | |
| 123540 | IgA Heavy Light Chains(HLC), S | 123533 | IgA K/L HLC Ratio | Ratio | 74869-9 | |
| Order Code | 123540 | |||||
| Order Code Name | IgA Heavy Light Chains(HLC), S | |||||
| Order Loinc | ||||||
| Result Code | 123531 | |||||
| Result Code Name | IgA Kappa, S | |||||
| UofM | g/L | |||||
| Result LOINC | 74864-0 | |||||
| Order Code | 123540 | |||||
| Order Code Name | IgA Heavy Light Chains(HLC), S | |||||
| Order Loinc | ||||||
| Result Code | 123532 | |||||
| Result Code Name | IgA Lambda, S | |||||
| UofM | g/L | |||||
| Result LOINC | 74865-7 | |||||
| Order Code | 123540 | |||||
| Order Code Name | IgA Heavy Light Chains(HLC), S | |||||
| Order Loinc | ||||||
| Result Code | 123533 | |||||
| Result Code Name | IgA K/L HLC Ratio | |||||
| UofM | Ratio | |||||
| Result LOINC | 74869-9 |