Reliability of self-sampling for accurate assessment of respiratory virus viral and immunologic kinetics

Alpana Waghmare; Elizabeth M Krantz; Subhasish Baral; Emma Vasquez; Tillie Loeffelholz; E. Lisa Chung; Urvashi Pandey; Jane Kuypers; Elizabeth R Duke; Keith R Jerome; Alexander L Greninger; Daniel B Reeves; Florian Hladik; E Fabian Cardozo-Ojeda; Michael Boeckh; Joshua T Schiffer

is the (which was not peer-reviewed) The copyright holder for this preprint . https://doi.org/10.1101/2020.04.03.20051706 doi: medRxiv preprint software. The light intensities from samples were interpolated using a four-parameter logistic fit 410 to a standard curve of electrochemiluminescence generated from the known concentrations of 411 the standards. The lower limit of detection for each marker can be found on the manufacturer's 412 website: https://www.mesoscale.com/~/media/files/handouts/assaylist.pdf. 413 414 Statistical analysis. For the foam versus flocked swab study, PCR results that were positive on 415 the qualitative assay but below the limit of detection were imputed as 500 copies per ml, using 416 the limit of detection divided by two. PCR results were log10-transformed and negative results 417 were assigned a value of 0. The concordance correlation coefficient (CCC) was used to 418 measure agreement of quantitative results between paired samples (foam versus flocked 419 swabs, left versus right nostril samples, sum versus maximum value from left and right 420 nostrils) 33 . For the longitudinal sampling study, cytokine results that were below the fitted curve 421 range were assigned the value of the lower limit of detection divided by two and results that 422 were above the fitted curve range were assigned the value of the upper limit of detection. 423