Accurate quantification of DNA using on-site PCR (osPCR) by characterizing DNA amplification at single-molecule resolution.

Despite the need in various applications, accurate quantification of nucleic acids still remains a challenge. The widely-used qPCR has reduced accuracy at ultralow template concentration and is susceptible to nonspecific amplifications. The more recently developed dPCR is costly and cannot handle high-concentration samples. We combine the strengths of qPCR and dPCR by performing PCR in silicon-based microfluidic chips and demonstrate high quantification accuracy in a large concentration range. Importantly, at low template concentration, we observe on-site PCR (osPCR), where only certain sites of the channel show amplification. The sites have almost identical ct values, showing osPCR is a quasi-single molecule phenomenon. Using osPCR, we can measure both the ct values and the absolute concentration of templates in the same reaction. Additionally, osPCR enables identification of each template molecule, allowing removal of nonspecific amplification during quantification and greatly improving quantification accuracy. We develop sectioning algorithm that improves the signal amplitude and demonstrate improved detection of COVID in patient samples.

A review of pooled‐sample strategy: Does complexity lead to better performance?

The outbreak of coronavirus disease 2019 (COVID‐19, caused by SARS‐Cov‐2) is a big challenge for global health systems and the economy. Rapid and accurate tests are crucial at early stages of this pandemic. Reverse transcription‐quantitative real‐time polymerase chain reaction is the current gold standard method for detection of SARS‐Cov‐2. It is impractical and costly to test individuals in large‐scale population screens, especially in low‐ and middle‐income countries due to their shortage of nucleic acid testing reagents and skilled staff. Accordingly, sample pooling, such as for blood screening for syphilis, is now widely applied to COVID‐19. In this paper, we survey and review several different pooled‐sample testing strategies, based on their group size, prevalence, testing number, and sensitivity, and we discuss their efficiency in terms of reducing cost and saving time while ensuring sensitivity.

COVID-19-another influential event impacts on laboratory medicine management.

BACKGROUND: Before public health emergencies became a major challenge worldwide, the scope of laboratory management was only related to developing, maintaining, improving, and sustaining the quality of accurate laboratory results for improved clinical outcomes. Indeed, quality management is an especially important aspect and has achieved great milestones during the development of clinical laboratories. CURRENT STATUS: However, since the coronavirus disease 2019 (COVID-19) pandemic continues to be a threat worldwide, previous management mode inside the separate laboratory could not cater to the demand of the COVID-19 public health emergency. Among emerging new issues, the prominent challenges during the period of COVID-19 pandemic are rapid-launched laboratory-developed tests (LDTs) for urgent clinical application, rapid expansion of testing capabilities, laboratory medicine resources, and personnel shortages. These related issues are now impacting on clinical laboratory and need to be effectively addressed. CONCLUSION: Different from traditional views of laboratory medicine management that focus on separate laboratories, present clinical laboratory management must be multidimensional mode which should consider consolidation of the efficient network of regional clinical laboratories and reasonable planning of laboratories resources from the view of overall strategy. Based on relevant research and our experience, in this review, we retrospect the history trajectory of laboratory medicine management, and also, we provide existing and other feasible recommended management strategies for laboratory medicine in future.

Analytical sensitivity comparison of 14 conventional and three rapid RT-PCR assays for SARS-CoV-2 detection.

Recent reports have compared the analytical sensitivities of some SARS-CoV-2 RT-PCR assays, but differences in the viral materials used for these evaluations made comprehensive conclusions difficult. We carried out a direct comparison of the analytical sensitivities of 14 conventional and three rapid RT-PCR assays for the detection of SARS-CoV-2. The comparison was performed utilizing a certified reference material for SARS-CoV-2 RNA that was serially two-fold diluted in RNA storage solution. Our results show that the analytical sensitivities of the 17 assays varied within an 8-fold range (100-800 copies/mL). Moreover, a trend with some rapid assays yielding slightly higher analytical sensitivities (2- to 4-fold) compared with conventional assays was observed. We conclude that most of the RT-PCR assays can be used for routine COVID-19 diagnosis, but some assays with the poorest analytical sensitivities may lead to false-negative results when used to identify asymptomatic individuals who can carry a low viral load but still be infectious. These findings should be kept in mind when selecting high-sensitivity and rapid assays.