![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=1735498504&Signature=K0LT4PXJDyT3lmDwfIFfpBNT1fLRQnXyIfJ1mobZzYYxyVsZmMXWP8kS9~IX2h-pR92ktLRxpoiVzYhNUfQJyUcN8pC66NFWTcMwgeB~iIXHsoT-OqP~qqpBt7XpNBdluo4X13g~2Vcfe-gYteXpeP-JL7xwKUAvTxdFzLMc6oirt5U8p9R~GgwYXMtJkV5ooy~VEbgJUkPuqjvzho4k-seOrX4G2dmM5-oa-fPF2MW3U5cftrjoO2OZA1FHi~8cLaC7g3mebA6Pj~4bT1JNAXgJzoXNYIkyBx95fy50f5gCIrqCI8hm3qy4pfprG25i9~VsGMKhHcLanSj0F22d6Q__&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.
