Abstract

GOLDSCHMIDT, Pablo. Pandemic and social inequiality: the popular neighborhoods of the Buenos Aires suburbs in preventive social isolation. Rev. argent. salud pública [online]. 2020, vol.12, suppl.1, pp.17-17.  Epub Dec 30, 2020. ISSN 1852-8724.

Emerging respiratory viral infections like the severe coronavirus disease (CoVID 19) caused by novel coronavirus 2 (SARS-CoV-2) require quality results for science-based responses. The reverse transcriptase polymerase chain reaction (rRT-PCR) is considered the gold standard for detecting SARS-CoV-2 (particularly in the acute phase of infection).

The aim of the present work was to analyze pitfalls during the search of viral genomes.

False negative conclusions are result of sampling timing, performances of swabbing, storage, and thawing and heat-infectivity inactivation. Samples with low biologic material also lead to false negatives. Qualitative controls to detect the presence of human DNA are available in several kits but they were not calibrated for quantification of human cell loads. Moreover, negativity cannot be reported for samples with delayed signals for the internal control (due to deficiency in extraction and/or retro transcription and/or or to the presence of rRT-PCR inhibitors).

The viral RNA that may have stick on gloves, on tubes, caps, etc. may produce false positives. The International Pharmacopoeias recommend for external contamination to test at least 10% of the samples. Couples of 10 negative contiguous to 10 positive controls randomly distributed should be therefore included in each series of 100 rRT-PCR tests. These improvements increase the cost of each determination (at least by 20% only for the reactants) and require additional resources.

Keywords : SARS-CoV-2; COVID-19; Reverse Transcriptase PCR; False Negative reactions; False Positive reactions.

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