With Hong Kong’s mass Covid-19 testing soon to be in place, concerns among the public over how the biological information will be captured and processed have led to privacy worries. I was astonished to find that lawmakers and professionals in the diagnostic industry were offering conspiracy theories about the test without substantial scientific evidence. Currently, a Covid-19 test can be performed using antibody- or nucleic acid-based approaches. The nucleic acid-based approach applies a laboratory technique called real-time polymerase chain reaction (RT-PCR) to test for the presence of viral RNA (ribonucleic acid) – a genetic piece of Covid-19 – in a deep-throat saliva sample or a nasopharyngeal swab. The RT-PCR test specifically amplifies a short region on the RNA sequence of the Covid-19 virus. If a viral RNA sequence is detected in the sample, the amplification is successful and presented as positive, or “+”. No DNA sequences are revealed by this test. The allegations against mass Covid-19 testing suggest that genomic or DNA information would be captured and transferred for different applications, like biometric tracking or producing a DNA mugshot that allows facial reconstruction. Those who make such allegations must know very little about whole genome (DNA) sequencing (WGS) a nd genotyping. A human genome is a long stretch of combinations of four DNA letters – A, T, C and G – running to 6.4 billion letters in all. Thus, sequencing a whole genome (WGS) – as opposed to a short strand of RNA – is a much more complex and expensive undertaking. Instead, scientists tend to apply a rapid technique called genotyping: scanning certain important, small regions in the genome known to be associated with major changes in phenotype, including physical traits (eye and skin colour) and disease traits, like cancer. The commercial DNA genetic tests offered by some companies use genotyping, not sequencing, to analyse multiple small regions in the genome. Gene-sequencing technology has not yet progressed to the point where it is feasible to sequence a person’s entire genome quickly and cheaply enough. There is, as yet, no reliable way of creating a DNA mugshot with limited genotyping information. Nevertheless, an individual’s genomic information should be protected. The government could require test laboratories to follow the guidelines outlined in the General Data Protection Regulation (GDPR) in the European Union or the Covid-19 Consumer Data Protection Act in the United States. The Hong Kong government has made the right decision to control the pandemic. Not only is the test scientifically sound, but the outcome from mass testing in Wuhan also suggests that the test helps to identify silent spreaders in the community. The fear that whole-genome DNA codes may be captured in the mass Covid-19 tests is unjustified, at least for now. Tin-Lap Lee, associate professor, School of Biomedical Sciences, Chinese University of Hong Kong