Table 1.

Xpert®cycle threshold values of serial dilutions of inactivated high-titer SARS-CoV-2 virus

Dilution	E gene	N gene	SPC
1 × 106 copies/mL	22.9	25.3	27.5
1 × 105 copies/mL	26.1	28.4	27.5
1 × 104 copies/mL	29	31.6	27.4
2.5 × 103 copies/mL	31.2	34.8	27.7
4.17 × 102 copies/mL	33.2	35.8	27.8
4.17 × 102 copies/mL in pool of 4 (104 copies/mL)*	0	0	28.1
4.17 × 102 copies/mL in pool of 6 (70 copies/mL)*	0	42.8	28

E = envelope; N = nucleocapsid; SPC = sample processing control.

These serial dilutions of inactivated virus were used to create standards for standard curve in Fig. 1.

^⁎Note: Manufacturer claimed LOD for Xpert® is 250 copies/mL (lowest concentration that can be reproducibly distinguished from a negative sample ≥95% of the time with 95% confidence).