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 Field Name  Data Description
Test Name  Kappa Light Chain Urine Random
Code  Kappa Lambda Light Chain Qnt Ur.
CPT Code  83883x2
Last Modified  5/7/2018 8:07:00 AM
Test Name  UrKappaLambda.
Patient Preparation  
Spec. Requirements  Urine (random or 24-hour)
Tube  Plastic urine container
Collection Volume  1.5 mL
Storage  Stable at room temperature 25(degrees)C for up to seven days or refrigerated at 2(degrees)C to 8(degrees)C for four weeks; longer when FROZEN at -20(degrees)C or lower
Routine TAT  
Days Test Performed  
Performed by BHS  None
See Availability  
Reference Lab  LabCorp of America
Reference Lab Code  121228 Free K+L Lt Chains,Qn,Ur
Clinical Use  Immunoglobulin molecules consist of two identical heavy chains (alpha, delta, epsilon, gamma, or mu) which define the immunoglobulin class and two identical light chains (kappa or lambda). Each light chain is covalently linked to a heavy chain and the two heavy chains are linked covalently at the hinge region. In healthy individuals, the majority of light chains in serum exists in this form, bound to heavy chain; however, low levels of free light chain (FLC) are found in serum of normal individuals due to the overproduction and secretion of FLC by the plasma cells. While the molecular weight of both light chains is approximately 22.5 kilodaltons, in serum, kappa free light chain (kappa-FLC) exists primarily as a monomer and lambda free light chain (lambda-FLC) as a covalently-linked dimer with a molecular weight of approximately 45 kilodaltons. This will lead to a differential glomerular filtration rate for kappa-FLC and lambda-FLC and may explain the observed ratio of kappa-FLC to lambda-FLC of 0.625 in serum compared to the ratio of bound kappa to lambda of 2.0. The laboratorywill perform FLC analysis on urine, but a serum sample is preferred for many reasons. Analogous to glucose metabolism,FLC spill into the urine only after the tubular reabsorptivecapacity is exceeded. Thus, the serum FLC ratio has been shown to be abnormal in patients with monoclonal gammopathy despite normal urine FLC ratios or normal urine immuno- fixation. Serum tests are also more sensitive for the detection of residual monoclonal FLC after treatment and forthe early detection of monoclonal FLC after relapse in patients with monoclonal gammopathy. FLC levels in urine arenormally low. In a healthy kidney, the tubular cells selectively reabsorb all FLC so their presence in urine is probably due to secretion into the urinary tract. The appearance of higher levels of polyclonal FLC in urine may be indicative of kidney or autoimmune disease. An abnormal urine FLC ratio may be indicative of malignant lymphoproliferative disease such as multiple myeloma. The monoclonal urinary FLC associated with lymphoid malignancy is called a Bence Jones protein.
Reference Range  
Critical Value  
Testing Sample Type  URINE RANDOM
Min Lab Testing Volume  1.0 mL
Special Handling  Values obtained with different assay methods should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy. This procedure does not provide serial monitoring; it is intended for one-time use only. If serial monitoring is required, please use the serial monitoring number 121243 to order.
Lab Notes  Ship the specimen as soon as possible.
Methodology  NEPH - Nephelometry
Limitations  Rejection Microbially-contaminated specimen; specimen containing particulate matter

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