Free light chains
|Category||Biochemistry >> Proteins|
The haematological neoplasms that arise through primarily tumours of the B-cell haematopoietic lineage and subsequent plasma cells comprise a wide range of disorders that include the multiple myelomas, Waldenström’s macroglobulinaemia, AL amyloidosis (primary systemic amyloidosis), heavy chain disease and the plasmacytomas. Disease is typically characterised by secretion of monoclonal immunoglobulins, their free light chain components or fragments thereof, and diagnosis and staging of disease progression often employs the systematic assay of these specific proteins over time.
Serum FLC assay is of greater clinical utility than urinary BJP assay in diagnosis of non-Ig secretory multiple myeloma. Stratification of risk for development of multiple myeloma in MGUS cohorts. Staging of established malignancy Assessment of response to chemotherapeutic intervention (especially with regard to AL amyloidosis, light chain and non-secretory multiple myeloma). Prognostic indicator/tumour marker for detection of residual tumour or cancer recurrence.
It is recommended that serum protein electrophoresis and serum free light chains (sFLC) are used to determine the presence of a paraprotein, which may indicate possible myeloma or monoclonal gammopathy of undetermined significance (NG35). Approximately 20% of cases of myeloma do not have a detectable intact immunoglobulin: do not use serum protein electrophoresis, sFLC or BJP alone to exclude a diagnosis of myeloma.
BJP analysis may prove useful where there are marginally increases/decreases in the serum free light chain ratio.
Free Kappa chains: 3.3-19.4 mg/L Free Lambda chains: 5.7-26.3 mg/L
For impaired renal function: sFLC Ratio reference range is 0.37 to 3.10
|Sample & container required||SST (gold top) or serum (red top)|
|Sample volume||0.5 mL|
|Transport storage||Stable at 2-8°C for 72 hours. Please freeze pending dispatch for analysis. Sample can be sent by first class post.|
|Turnaround time||1 week|
Grossly haemolysed samples are unsuitable for this assay.
Serum Free Light Chain Local Guidance: