Description

Presslauer et al used measurements of kappa and lambda light chains in the cerebrospinal fluid (CSF) to help support the diagnosis of multiple sclerosis. The authors are from Wilhelminenspital in Vienna.


 

Parameters:

(1) serum kappa and lambda light chain concentrations in mg/L

(2) CSF kappa and lambda light chain concentrations in mg/L

(3) serum albumin in mg/L (1000 times value in g/L)

(4) CSF albumin by nephelometry in mg/L

 

free light chain index =

= (CSF free light chains in mg/L) * (serum albumin in mg/L) / ((serum free light chains in mg/L) * (CSF albumin in mg/L))

 

where:

• According to Tietz's Clinical Guide to Laboratory Tests the reference range for CSF albumin by nephelometry is 100 to 300 mg/L.

• According to Tietz's Clinical Guide to Laboratory Tests the reference range for serum free light chans is 3.3 to 19.4 mg/L for kappa and 5.7 to 26.3 mg/L for lambda..

• The units for serum and CSF free light chains are specified. The units for serum and CSF albumin are not given but are presumed to be mg/L.

• If kappa light chains are too low to be measured then 0.06 mg/L is used in the calculation.

• If lambda light chains are too low to be measured then 0.08 mg/L is used in the calculation.

 

Interpretation:

• In normal controls the KFLC index had a mean value of 1.3.

• In normal controls the LFLC index had a mean value of 1.4.

• In patients with multiple sclerosis the KFLC index ranges from 20 to 160. Kappa light chains in the CSF were measured from 1.4 to 10 mg/L.

• In patients with multiple sclerosis the LFLC index ranges from 3 to 42.

• Neuroborreliosis gave KFLC index up to 25.

 


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