Table 3.

RNA extraction conditions of the available studies.

Reference The papers marked with an asterisk (*) were not certified by peer review (preprints)	Location given in alphabetical order	RNA extraction kit	Use of surrogate control	Final elution volume	Storage of extracted samples
[34]	Australia	Method A •5-mL bead tube from RNeasy PowerWater Kit for electronegative membrane •Precellys 24 for sample homogenisation at 3 x 20 sec at 8000 rpm (10 sec intervals) •RNeasy PowerMicrobiome kit for RNA extraction Method B •RNA extraction with RNeasy PowerMicrobiome kit •QIAcube Connect Platform for extraction	Not reported	100 μL	−80 °C
[35]	Australia	•RNeasy PowerMicrobiome kit	Not reported	100 μL	Not reported
[4]	Australia	•5-mL bead tube from RNeasy PowerWater Kit for electronegative membrane by adding 990 μL of buffer PM1 and 10 μL of β-mercaptoethanol •Precellys 24 for sample homogenisation at 3 x 20 sec at 10000 rpm (10 sec intervals) •10000xg for 5 min to pellet filter debris and beads •RNeasy PowerMicrobiome kit and QIAcube Connect Platform for RNA extraction from 450 μL lysate	Not reported	100 μL	Not reported
[7]*	Brazil	•QIAmp viral RNA Mini kit	Not reported	200 μL	Not reported
[25]*	France	•Nucleospin RNA Virus Kit	VP40-encoding RNA of Ebola virus	Not reported	Not reported
[6]*	France	•PowerFecal Pro kit •OneStep PCR inhibitor removal kit	Not reported	Not reported	Not reported
[32]*	India	•NucleoSpin RNA Virus kit	MS2 phage	Not reported	Not reported
[27]*	Israel	RNeasy mini kit and easyMAG kit	Not reported	Not reported	−80 °C
[22]	Italy	•20 min of lysis •Centrifugation at 2000 x g for 1 min •Addition of magnetic silica beads to supernatant •RNA purification using the OneStep PCR Inhibitor Removal kit	Not reported	Not reported	Not reported
[24]*	Italy	•NucliSENS miniMAG with magnetic silica •Lysis buffer quantity twice the sample volume •Lysis phase prolonged for 20 minutes •100 μL magnetic silica beads per sample	Not reported	Not reported	Not reported
[9]*	Italy	QIamp viral RNA mini kit	Not reported	Not reported	Not reported
[33]*	Japan	•RNeasy PowerWater kit •QIAmp Viral RNA Mini kit	Not reported	•60 μL •50 μL	Not reported
[26]	Spain	•150 μL of concentrated sample mixed with 25 μL plant RNA Isolation aid and 600 μL of lysis buffer followed by pulse vortexing •Centrifugation for 5 min at 10000 x g to remove debris •RNA extraction with the Nucleospin RNA virus kit	Porcine epidemic diarrhea virus (PEDV) and mengovirus vMC0 (MgV)	100 μL	Not reported
[21]* [38]	The Netherlands	•RNeasy PowerMicrobiome kit •Nuclisens kit	Not reported	100 μL	Not reported
[28]*	Turkey	•QIAmp cador Pathogen Mini Kit •QuantiNova Pathogen + IC kit	Infectious Bronchitis Virus	Not reported	Not reported
[29]*	USA	AllPrep PowerViral DNA/RNA Kit	Not reported	50 μL	Not reported
[30]	USA	ZR Viral RNA kit	Pseudomonas bacteriophage Φ6	100 μL	Not reported
[31]*	USA	Trizol	Not reported	Not reported	Not reported
[8]*	USA	RNeasy Mini Kit	Not reported	40 μL	Not reported