## 3 Results
### Reliability of the qFCM for Viral Titration  
To evaluate the procedure for viral quantification, qFCM was applied using ten-fold dilutions of the virus (titrated by two methods: plaque forming units and endpoint dilution), and the results are shown in Table 3. Surprisingly, the MESF values corresponding to the lowest MOIs (0.00001 and 0.000001) were higher than the previous ones; however, this was corrected when the percentage of infected cells at each MOI was considered to calculate the MFI values. Figure 2: Repeatability and reproducibility. Linear regression between the observed fluorescence (AFI) and the expected MESF reported by the manufacturer of the beads employed as standard. \begin{table}
\begin{tabular}{l c c c c c c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**AFI**} & \multicolumn{6}{c}{**MESP**} \\ \hline  & **Replica 1** & **Replica 2** & **Replica 3** & **Mean** & **SD** & **CV** & **Replica 1** & **Replica 2** & **Replica 3** & **Mean** & **SD** & **CV** \\ \hline Beads & & & & & & & & & & & & & \\ B1 & 15.07 & 15.14 & 15.39 & 15.20 & 0.17 & 1.1 & 1929 & & 1929 & 0 & 0 \\ B2 & 36.10 & 36.30 & 37.93 & 36.60 & 0.70 & 1.9 & 8750 & & 8750 & 0 & 0 \\ B3 & 127.85 & 127.91 & 134.23 & 130.00 & 3.67 & 2.8 & 34,864 & 34,864 & 0 & 0 \\ B4 & 406.90 & 425.17 & 463.92 & 432.00 & 29.12 & 6.7 & 127,311 & 127,311 & 0 & 0 \\ B5 & 1197.54 & 1219.18 & 1325.49 & 1247.40 & 68.49 & 5.5 & 421,992 & & 421,992 & 0 & 0 \\ \hline Samples & & & & & & & & & & \\ Blank & 102.50 & 105.80 & 112.70 & 107.00 & 5.20 & 4.9 & 23,579.62 & 24,483.96 & 26,991.86 & 24,818.48 & 1435.66 & 5.8 \\ C-MOCK & 140.20 & 131.50 & 145.40 & 139.03 & 7.02 & 5.1 & 34,205.24 & 31,699.19 & 35,772.33 & 33,873.88 & 2029.41 & 6.0 \\ FITC\({}^{*}\) & 1667.40 & 1656.80 & 1795.20 & 1699.80 & 82.75 & 4.9 & 638,282.09 & 642,529.82 & 706,821.61 & 662,551.17 & 38,400.90 & 5.8 \\ \hline  & \multicolumn{6}{c}{**AFI**} & \multicolumn{6}{c}{**Repeathability Day 2**} & \multicolumn{6}{c}{**MESP**} \\ \hline  & **Replica 1** & **Replica 2** & **Replica 3** & **Mean** & **SD** & **CV** & **Replica 1** & **Replica 2** & **Replica 3** & **Mean** & **SD** & **CV** \\ \hline Beads & & & & & & & & & & & \\ B1 & 18.41 & 17.05 & 17.64 & 17.70 & 0.68 & 3.9 & 1929 & 1929 & 0 & 0 \\ B2 & 38.67 & 36.72 & 38.01 & 37.80 & 0.99 & 2.6 & 8750 & & 8750 & 0 & 0 \\ B3 & 152.00 & 129.09 & 117.91 & 335.00 & 7.91 & 5.9 & 34,864 & 34,864 & 0 & 0 \\ B4 & 457.93 & 487.65 & 449.49 & 485.02 & 20.04 & 4.3 & 127,311 & 127,311 & 0 & 0 \\ B5 & 1495.67 & 1410.55 & 1263.89 & 1990.04 & 117.24 & 8.4 & 421,992 & 421,992 & 0 & 0 \\ \hline Samples & & & & & & & & & & \\ Blank & 96.51 & 95.59 & 90.93 & 94.30 & 2.99 & 3.2 & 20,011.7 & 19,785.44 & 18,645.63 & 19,480.93 & 732.18 & 3.8 \\ C-MOCK & 178.71 & 145.90 & 130.96 & 151.90 & 24.43 & 16.1 & 41,586.38 & 32,668.35 & 28,751.93 & 34,415.55 & 6975.37 & 19.1 \\ FITC\({}^{*}\) & 1847.76 & 1949.35 & 1761.12 & 1852.70 & 133.10 & 7.2 & 668,527.32 & 705,307.84 & 628,507.58 & 668,087.58 & 40,337.94 & 6.0 \\ \hline  & \multicolumn{6}{c}{**AFI**} & \multicolumn{6}{c}{**Repeathability Day 3**} & \multicolumn{6}{c}{**MESP**} \\ \hline  & **Replica 1** & **Replica 2** & **Replica 3** & **Mean** & **SD** & **CV** & **Replica 1** & **Replica 2** & **Replica 3** & **Mean** & **SD** & **CV** \\ \hline Beads & & & & & & & & & & & \\ B1 & 16.69 & 16.28 & 15.34 & 16.10 & 0.69 & 4.3 & 1929 & 1929 & 0 & 0 \\ B2 & 41.19 & 38.93 & 37.48 & 39.20 & 1.87 & 4.8 & 8750 & 8750 & 0 & 0 \\ B3 & 145.51 & 130.46 & 1281.55 & 1350.40 & 10.00 & 7.4 & 34,864 & 34,864 & 0 & 0 \\ B4 & 490.08 & 543.75 & 434.09 & 489.31 & 44.84 & 9.2 & 127,311 & 127,311 & 0 & 0 \\ B5 & 1560.61 & 1544.34 & 1314.78 & 1473.24 & 137.47 & 9.3 & 421,99