The determination of free light chains by
immunoturbidimetry and ELISA
Vávrová J.1, Friedecký B.1, Tichý M.1, Holečková M.1, Maisnar V.2, Hájek R.3
1Ústav klinické biochemie a diagnostiky LF UK a FN Hradec Králové 2OKH, II. interní klinika LF UK a FN Hradec Králové 3Interní hematoonkologická klinika FN a LF MU, Brno-Bohunice
Objective: Verification of measurement procedures for serum free light chains analysis.
Methods: Immunoturbidimetric measurement with using the FreeLite kit (The Binding Site), adapted on the Modular P
(Roche). ELISA method performed by kit BioVendor.
Results: The ratio kappa/lambda of blood donors values in men and women was from 0.53 to 1.92 by use FreeLite kit
and from 0.24 to 1.17 by ELISA method. We obtained measurement precision as follows: kappa (FreeLite) 5.6–6.9%,
6.6–11.0% (ELISA), lambda 6.1–9.2% by FreeLite and 7.3–8.6% by ELISA kit.
We assessed the influence of sample dilution on the results. It is necessary to verify dilution in each pathologically
Regression analysis is expressed by equation y = -9.84 + 1.53 x and Pearson regression coefficient is r = 0.73.
We found 58.9% results obtained with immunoturbidimetry, but only 45.5% of results obtained by ELISA method out off
reference limit. Four and a half % of pathologic results showed disagreement frequency in paired results while in results
inside reference interval there was a disagreement frequency even 17.8%.
Conclusion: It is unsuitable to consider the measurement of free light chains in serum as a routine event. This determination
requires careful work and high professional level of laboratory personal.
serum free light chains, ELISA, immunoturbidimetry.