Table 2.

Rates of recovery of inoculated PV1 from a sediment sample using indirect methods^a

Method	Elution buffer	Concn method (reference)	Total (flow 1)			Elution and concnb recovery rate (%)	Extraction and RT-qPCR (flow 2)			No. of samples
			No. of copies detected/no. of inoculated copies	Recovery rate (%)			No. of copies detected/no. of inoculated copies	Recovery rate (%)
				GM	GSD			GM	GSD
A	Glycine-NaOH	Filtration (5)	1.9 × 106/1.1 × 108	1.8	0.17	1.8	1.7 × 108/1.1 × 108	165	0.06	3
B	Glycine-NaOH	Filtration (12)	5.7 × 106/1.1 × 108	5.4	0.53	5.4	1.2 × 108/1.1 × 108	112	0.20	9
C	TE + Laureth-12	Filtration (12)	6.5 × 105/1.1 × 108	0.61	0.11	0.61	1.4 × 108/1.1 × 108	135	0.05	3
D	Glycine-NaOH	PEG precipitation	0/1.1 × 108	—	—	Unknown	0/1.1 × 108	—	—	3
E	TE + Laureth-12	PEG precipitation	1.9 × 105/1.1 × 108	0.18	0.11	0.18	1.1 × 108/1.1 × 108	106	0.02	3

^aGM, geometric mean; GSD, geometric standard deviation; —, not detected.

^bRecovery rates in the elution and concentration steps were calculated on the basis of the assumption that the recovery rate for the extraction and RT-qPCR steps was 100%.