A dual-label time-resolved fluorescence immunoassay for the simultaneous determination of ferritin and β 2 -microglobulin.

BACKGROUND: Lymphocytic leukemia is a kind of primary malignant tumor of hematopoietic tissue. The aim was to establish a dual-label time-resolved fluorescence immunoassay (TRFIA) for the simultaneous determination of ferritin (FER) and β2 -microglobulin (β2 -MG) for the early screening and follow-up surveillance of lymphocytic leukemia.

METHODS: The sandwich immunoassay was used to detect the concentration of FER, and the competitive immunoassay was used to detect the concentration of β2 -MG in serum. FER in serum was captured by anti- FER antibody immobilized on microtiter wells, and then banded together with another anti- FER labeled with europium(III) Eu3+ chelate, followed by fluorescence measurement using time-resolved fluorometry (TRF). Sm3+ labeled β2 -MG and β2 -MG samples were added to compete with a certain amount of anti-β2 -MG antibody, followed by fluorescence measurement using TRF. The performance of this dual-label TRFIA was evaluated using the clinical blood and compared with the commercial assays.

RESULTS: The linear correlation coefficient (R2 ) of the FER and β2 -MG standard curves were 0.9914 and 0.9927, respectively. The sensitivity for FER detection was 8 ng/mL (dynamic range 0-1000 ng/mL), the average recovery was 100.51%; The sensitivity for β2 -MG detection was 1 ng/mL (dynamic range 0-1000 ng/mL), the average recovery was 101.02%. High correlation coefficients (R2 ) were obtained between the commercial assays (R2 =.9966 for FER, and R2 =.9897 for β2 -MG).

CONCLUSION: The present dual-label TRFIA has high sensitivity, specificity, and accuracy in clinical sample analysis. It is an effective detection method for the early screening and follow-up surveillance of the acute and chronic lymphocytic leukemia.