![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=1764783406&Signature=2tUnQhfyyvAT14jNZl1IyMRfpEiMIiGXFxxLEQhVkbf-bPdvGdjl6yNd0-dWcwc191JZnctiTU7wETAbD8KUG6hx-m~uXRQAG7-R~1miCh7iDS8gpdY2B1pPF0XAm0JtnkQLYz6UOSq35IZhaITMYtuwLPDmYwcAy-Nt6JeC6frGA9ApBMIOUC~LtX9nxOLbIa3hJqlbnINagFdbPU2Nb7spY~yYQ0oNYg~-MSINUzU1qBG1vZoRQMKhP9gFl7xLLpSrneVmDl34IV6JihYVNKsX7Zzcrpu5qGxdnkH1fZvBYPOwj9v9J9DjUyeJdzP6KRCD1rROgE5QmdDqhu7ZNQ__&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.
