General Information

UPHSM LIS Test #: 028484
Testing Time: 1-3 Days
Testing Lab: Labcorp

Specimen Info
Only 1 specimen type required, unless otherwise specified

Volume: 1.5 mL
Temperature: Refrigerated
Tube Type: Serum
Collection Info:
Minimum Volume: 0.8 mL
Container: Red-top tube or gel-barrier tube
Collection: Sample should be allowed to clot and the serum separated as soon as possible to prevent hemolysis. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Storage Instructions: Refrigerate; samples are stable for 21 days at 2°C to 8°C. For longer storage, freeze at -20°C.

Specimen Acceptability

Cause for Rejection:
Microbially-contaminated specimen; specimen containing particulate matter; lipemic or hemolyzed specimen



Clinical Utilities

Free light chain (FLC) results should be considered under the following categories and investigated appropriately (κ = kappa free light chain; λ = lambda free light chain). 1. Normal samples: Serum κ, λ, and κ:λ are all within the normal ranges. If accompanying serum electrophoretic tests are normal, it is most unlikely that the patient has a monoclonal gammopathy. 2. Abnormal κ:λ ratios: Support the diagnosis of a monoclonal gammopathy and require an appropriate tissue biopsy. Borderline elevated κ:λ ratios occur with renal impairment and may require appropriate renal function tests. 3. Low concentrations of κ, λ, or both: Indicate bone marrow function impairment. 4. Elevated concentrations of both κ and λ with a normal κ:λ ratio: May be due to the following: • Renal impairment (common) • Overproduction of polyclonal FLCs from inflammatory conditions (common) • Biclonal gammopathies of different FLC types (rare) 5. Elevated concentrations of both κ and λ with an abnormal κ:λ ratio: Suggest a combination of monoclonal gammopathy and renal impairment. Interpretation of Serum-free Light Chain Results Kappa (κ) Lambda (λ) κ:λ Ratio Interpretation Key: BM = bone marrow; MG = monoclonal gammopathy; pIg = polyclonal immunoglobulin. Normal Normal Normal Normal serum Low Low Normal BM suppression without MG High MG with BM suppression Low Normal Normal Normal serum or BM suppression Low MG with BM suppression High Low Normal Low High MG with BM suppression Normal Normal serum or BM suppression Normal High MG with BM suppression Low High Normal pIg increase or renal impairment Low MG without BM suppression High Low High MG with BM suppression Normal High MG without BM suppression Normal pIg increase or renal impairment High Normal High MG with renal impairment Low

CPT Codes


* The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding
is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Reference Range

See Report.