Rand KH, Pieretti M, Arcenas R, Beal SG, Houck H, Boslet E, Lednicky JA. Semi-quantitative Influenza A population averages from a multiplex respiratory viral panel (RVP): potential for reflecting target sequence changes affecting the assay.
Virol J 2017;
14:128. [PMID:
28709460 PMCID:
PMC5513141 DOI:
10.1186/s12985-017-0796-3]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 07/03/2017] [Indexed: 02/07/2023] Open
Abstract
Background
Yearly influenza virus mutations potentially affect the performance of molecular assays, if nucleic acid changes involve the sequences in the assay. Because individual patient viral loads depend on variables such as duration of illness, specimen type, age, and immunosuppression, we examined seasonal population averages of positive tests to smooth inherent variability.
Methods
We studied the population seasonal averages of the semi-quantitative nAMPs for the influenza matrix and hemagglutinin genes in the GenMark (Carlsbad, CA) Respiratory Viral Panel assay between 3 institutions over 3 Influenza seasons.
Results
Population average nAMPs were strikingly consistent between separate institutions, but differed substantially between H3N2 and H1N1 seasons. In the 2012–2013 and 2014–2015 influenza seasons, matrix gene H3N2 nAMP averages were 50–70% less than those of the same assay in the 2013–2014 H1N1 season. Influenza strains representative of these seasons were grown in tissue culture and when the supernatant virus was adjusted to the same copy number using a TaqMan assay, the same relative differences were reproduced in the RVP assay. Because the sequences for the PCR and PCR product detection in the GenMark assay are proprietary, the manufacturer provided single stranded DNA matching the capture probe for the representative H3N2 (3 mismatches) and H1N1 strains (2 different mismatches). Equimolar concentrations of these synthetic DNA sequences gave average nAMP values that closely correlated with the average nAMPS of the representative strains and their respective seasonal averages.
Conclusions
Seasonal averages of semi-quantitative data may provide a means to follow assay performance as a reflection of the effects of molecular drift.
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