In a 10-L extension reaction, an excess of a template oligonucleotide (5Ј-iC-CGTATGGGCTCACCTCGCTGTG-3Ј) at 150 nmol/L was combined with a control extension sequence at 100 nmol/L in EraGen MC TSE solution 35 (prod. no. PN1236; EraGen Biosciences, Inc.) with 100 mol/L each deoxynucleotide triphosphate, 1.5 mol/L diGTP-biotin, and 1ϫ Titanium Taq (Clontech). Each control extension oligonucleotide was composed of a 5Ј sequence complementary to each of the EraCode sequences, a three-carbon spacer, and a 3Ј sequence complementary to the template oligonucleotide (5Ј-CACAGC-GAGGTGAGCCCA-3Ј). Reactions were subjected to the following thermal cycling protocol: 30 s at 95°C and 1 min at 65°C. Each 10-L extension reaction was then hybridized to the EraCode bead mixture according to the described hybridization protocol. In addition, to mimic MultiCode conditions, unextended TSEs to the other EraCodes were also added.