![Fig. 1. Scheme of the DCI assay. / The scheme depicts the steps of the assay for both normal (left) and NTBI-containing sera (right). The iron is depicted as a filled circle and the Tf molecules denoted by ‘T’. Step 1: Serum samples are mixed with reagent A (HBS containing 2.5 μM fluorescein-DFO [Fl-DFO, *]) or reagent B (same as reagent A, but containing 100 μM DFO, **) in the wells. In reagent A the accessible Fe binds to the Fl-DFO and quenches its fluorescence, whereas in reagent B the Fe binds to the excess nonfluorescent DFO rather than to Fl-DFO. Step 2: Fluorescence is determined after a 2-hour incubation. In normal serum, the ratio of fluorescence of samples treated with reagent A and B is near 1, whereas in Fe-containing serum, the fluorescence in reagent A is lower than in B, giving a ratio less than 1. The ratio of the fluorescence readings (A/B) is inversely proportional to the concentration of DCI in the original sample.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/97/3/10.1182_blood.v97.3.792/6/h80310628001.jpeg?Expires=1724231778&Signature=HBTksQ4Wc7joIMGMoL3AsPNaQR8oppuejX8Bek~CM7eRUAh6E8EvJywRWg47r5q1UP6I7U4NSNFvJGXmiyW80kqhfYI3LRnpHQxfSC9IVy3AbqkVQyXfLHi8KAzzC8OZgE9f8zicVX3bY8nT3tZdtvKqXZ0fNC1lnktVUxXWcm~9rcL~VgaVZh5IKuNnYdk~B6y9vnV3g9sb-pUasr7qW17U5-iFUsIf6xHgzOMYSSGUkvmTF-VP4J~RSiOuo0VynvCCLDq9zss1am3jucTd0oqdiUuaWzGRAPhijxZrVN5WgUlyUrGygmv5Dez9NMdP59TlaR~-lcgeUFTHNbJBHw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Scheme of the DCI assay.
The scheme depicts the steps of the assay for both normal (left) and NTBI-containing sera (right). The iron is depicted as a filled circle and the Tf molecules denoted by ‘T’. Step 1: Serum samples are mixed with reagent A (HBS containing 2.5 μM fluorescein-DFO [Fl-DFO, *]) or reagent B (same as reagent A, but containing 100 μM DFO, **) in the wells. In reagent A the accessible Fe binds to the Fl-DFO and quenches its fluorescence, whereas in reagent B the Fe binds to the excess nonfluorescent DFO rather than to Fl-DFO. Step 2: Fluorescence is determined after a 2-hour incubation. In normal serum, the ratio of fluorescence of samples treated with reagent A and B is near 1, whereas in Fe-containing serum, the fluorescence in reagent A is lower than in B, giving a ratio less than 1. The ratio of the fluorescence readings (A/B) is inversely proportional to the concentration of DCI in the original sample.
