ABSTRACT
Stratifying patients according to disease severity has been a major hurdle during the COVID-19 pandemic. This usually requires evaluating the levels of several biomarkers, which may be cumbersome when rapid decisions are required. In this manuscript we show that a single nanoparticle aggregation test can be used to distinguish patients that require intensive care from those that have already been discharged from the intensive care unit (ICU). It consists of diluting a platelet-free plasma sample and then adding gold nanoparticles. The nanoparticles aggregate to a larger extent when the samples are obtained from a patient in the ICU. This changes the color of the colloidal suspension, which can be evaluated by measuring the pixel intensity of a photograph. Although the exact factor or combination of factors behind the different aggregation behavior is unknown, control experiments demonstrate that the presence of proteins in the samples is crucial for the test to work. Principal component analysis demonstrates that the test result is highly correlated to biomarkers of prognosis and inflammation that are commonly used to evaluate the severity of COVID-19 patients. The results shown here pave the way to develop nanoparticle aggregation assays that classify COVID-19 patients according to disease severity, which could be useful to de-escalate care safely and make a better use of hospital resources.
ABSTRACT
BACKGROUND: Clinical recovery does not mean full recovery. It is necessary to explore the aftereffects of COVID-19 in patients and compare the laboratory features of COVID-19 and other viral pneumonias in the recovery stages. METHODS: Forty-seven cases of COVID-19 and 45 cases of other viral pneumonias (control) were included in this study. The laboratory parameters were compared between COVID-19 and control patients as well as severe and moderate COVID-19 patients from the clinical recovery stage to the 4 weeks postdischarge recovery stage. RESULTS: A higher RDW-CV level and neutrophil percentage and lower levels of total proteins, lymphocytes, eosinophils, and MCH were found in COVID-19 patients compared with those in controls from the clinical recovery to the postdischarge recovery stages. Further analysis showed that decreases in lymphocytes, total proteins, and SOD and elevations in neutrophils, FDP, CRP, and ESR were more common in severe than moderate cases of COVID-19 during hospitalization; however, differences in these indicators, except total proteins, were not observed in the postdischarge recovery stages. Additionally, only 76.9% of COVID-19 patients were positive for IgG antibodies against SARS-CoV-2 in the convalescence stage, and one patient that was negative for specific IgG was reinfected. CONCLUSIONS: This study demonstrated that patients recovering from COVID-19 might need better care than that patients with other viral pneumonias due to the possibility of having poor immunity and nutritional conditions. These findings provide new insights to improve the understanding of COVID-19 and improve care for patients affected by these kinds of pandemics in the future.