Immunoglobulin Free Light Chains, Serum
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Monitoring patients with monoclonal light chain diseases but no M-spike on protein electrophoresis
Profile Information A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
|Test ID||Reporting Name||Available Separately||Always Performed|
|KFLC||Kappa Free Light Chain, S||No||Yes|
|LFLC||Lambda Free Light Chain, S||No||Yes|
|KLR||Kappa/Lambda FLC Ratio||No||Yes|
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
The following algorithms are available in Special Instructions:
-Laboratory Approach to the Diagnosis of Amyloidosis
-Laboratory Screening Tests for Suspected Multiple Myeloma
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Immunoglobulin Free Light Chains, S
Free Light Chains
Kappa-Free Light Chain
Lambda-Free Light Chain
Serum Free Light Chains
Kappa-Free Light Chain
Lambda-Free Light Chain
Serum Free Light Chains
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
If urine is being submitted on the same patient for TLCU/87934 Immunoglobulin Total Light Chains, Urine; order that test under a different order.
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 1 mL
Forms: If not ordering electronically, submit a General Request Form (Supply T239) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild OK; Gross OK
Mild OK; Gross reject
Mild OK; Gross OK
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Serum||Refrigerated (preferred)||14 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The monoclonal gammopathies are characterized by a clonal expansion of plasma cells that secrete a monoclonal immunoglobulin (Ig). The monoclonal Ig secreted by these cells serves as a marker of the clonal proliferation, and the quantitation of monoclonal protein can be used to monitor the disease course.
The monoclonal gammopathies include multiple myeloma (MM), light chain multiple myeloma (LCMM), Waldenstrom’s macroglobulinemia (WM), nonsecretory myeloma (NSMM), smoldering multiple myeloma (SMM), monoclonal gammopathy of undetermined significance (MGUS), primary systemic amyloidosis (AL), and light chain deposition disease (LCDD).
Monoclonal proteins are typically detected by serum protein electrophoresis (SPEP) and immunofixation (IF). However, the monoclonal light chain diseases (LCMM, AL, LCDD) and NSMM often do not have serum monoclonal proteins in high enough concentration to be detected and quantitated by SPEP.
A sensitive nephelometric assay specific for kappa free light chain (FLC) that doesn’t recognize light chains bound to Ig heavy chains has recently been described. This automated, nephelometric assay is reported to be more sensitive than IF for detection of monoclonal FLC. In some patients with NSMM, AL, or LCDD the FLC assay provides a positive identification of a monoclonal serum light chain when the serum IF is negative. In addition, the quantitation of FLC has been correlated with disease activity in patients with NSMM and AL.
See Laboratory Approach to the Diagnosis of Amyloidosis and Laboratory Screening Tests for Suspected Multiple Myeloma in Special Instructions.
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.
KAPPA-FREE LIGHT CHAIN
LAMBDA-FREE LIGHT CHAIN
KAPPA/LAMBDA FLC RATIO
The specificity of this assay for detection of monoclonal light chains relies on the ratio of free kappa and lambda light chains. Once an abnormal free light chain (FLC) K/L ratio has been demonstrated and a diagnosis has been made, the quantitation of the monoclonal light chain is useful for monitoring disease activity.
Changes in FLC quantitation reflect changes in the size of the monoclonal plasma cell population. Our experience to date is limited, but changes of >25% or trending of multiple specimens are needed to conclude biological significance.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Elevated kappa and lambda free light chain (FLC) may occur due to polyclonal hypergammaglobulinemia or impaired renal clearance. A specific increase in FLC (eg, FLC K/L ratio) must be demonstrated for diagnostic purposes.
Moderate to marked lipemia may interfere with the ability to perform testing.
Studies at Mayo Clinic have shown that in some patients with urine monoclonal light chains and negative serum immunofixation (IF), the free light chain (FLC) assay can identify monoclonal FLC in the serum. These studies support the increased sensitivity of the nephelometric FLC assay. In a series of patients with primary systemic amyloid treated by stem cell transplantation, the quantitation and monitoring of FLC predicted organ response (eg, disease course).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Drayson M, Tang LX, Drew R, et al: Serum free light chain measurements for identifying and monitoring patients with nonsecretory multiple myeloma. Blood 2001;97(9):2900-2902
Method Description Describes how the test is performed and provides a method-specific reference
The quantitation of free light chain (FLC) by nephelometry uses free light-chain antisera from The Binding Site, Ltd., and is performed on the Siemens Nephelometer II.(Bradwell AR, Carr-Smith HD, Mead GP, et al: Highly sensitive, automated immunoassay for immunoglobulin free light chains in serum and urine. Clin Chem 2001;47:673-680)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Saturday; Continuously until 3 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Same day/1 day
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83883 x 2
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|KFLC||Kappa Free Light Chain, S||36916-5|
|KLR||Kappa/Lambda FLC Ratio||48378-4|
|LFLC||Lambda Free Light Chain, S||33944-0|