Urine SARS-CoV-2 RNA is a predictor of COVID-19 – Community News

Urine SARS-CoV-2 RNA is a predictor of COVID-19

The coronavirus disease (COVID-19) is highly contagious. It is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which belongs to the seven-member beta coronavirus cluster, which includes SARS and Middle East Respiratory Syndrome (MERS).

Methods used to screen and diagnose SARS-CoV-2 infection include detecting SARS-CoV-2 nucleic acid, SARS-CoV-2 specific antibody and antigen. Antigen-based diagnostic tests are less sensitive than reverse transcription polymerase chain reaction (RT-PCR) based tests, but they are faster and easier alternatives.

The positive rates of SARS-CoV-2 nucleic acid in different body fluids are variable, indicating a clear pattern of persistence and clearance of viral RNA in body fluids of COVID-19 patients. In addition, the positive rates detected in extrapulmonary samples are usually lower than those observed in nasopharyngeal swabs.

It was also found that under certain specific circumstances SARS-CoV-2 could infiltrate from the bloodstream into the renal parenchyma and eventually lead to kidney damage and the excretion of viruses through the urine.

Acute kidney injury (AKI) is a common complication in hospitalized patients with severe COVID-19 symptoms, despite a low urinary virus RNA positive rate in COVID-19 patients.

Urinary SARS-CoV-2 RNA is an indicator of the progression and prognosis of COVID-19

Urinary SARS-CoV-2 RNA is an indicator of the progression and prognosis of COVID-19

The study

A new study published in the journal Diagnostics was based on the hypothesis that detecting urinary SARS-CoV-2 nucleic acid – which can result in renal and cardiovascular endothelial destruction to facilitate viral entry into the renal parenchyma – could be used as a specific biomarker to assess the severity of COVID-19 to indicate.

The current study included 53 patients diagnosed with COVID-19 at the Renmin Hospital of Wuhan University from January 31, 2020 to February 18, 2020. Participants were tested for SARS-CoV-2 nucleic acid in urine samples using quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis.

Based on the results, the patients were divided into two groups: the urinary SARS-CoV-2 negative group (URNA, 38 cases) and the positive group (URNA+, 15 cases). In addition, a retrospective study was conducted on the patients’ clinical characteristics, pre-existing diseases and laboratory tests.

The diagnosis of COVID-19 pneumonia was made by following the guidelines for prevention and control of novel coronavirus pneumonia. This research was funded by the National Natural Science Foundation of China and the National Institutes of Health.


The median age of patients was 52 years (age range 42-66 years). Results of real-time quantitative reverse transcription PCR (qRT-PCR) analysis showed that 38 of 53 patients were urine SARS-CoV-2 negative (URNA). While the urinary SARS-CoV-2 positive (URNA+) patients were older and more likely to have chest tightness and shortness of breath. Nevertheless, the latter group showed no significant differences in the gender-based distribution, general symptoms, radiological occurrence, metabolic diseases or co-morbidities.

Meanwhile, youRNA+ patients developed more severe respiratory distress with manifestations of lower arterial oxygen pressure (PaO2) and oxygen saturation (SaO2), as examined by arterial blood gas analysis. In addition, leukopenia and lymphocytopenia were more frequently detected in routine blood tests of URNA+ patients than those in blood tests from URNA patients

In addition, evaluation of the immune profile identified a more frequent increase in serum C-reactive protein (CRP) and immunoglobulin (Ig) E in URNA+ patients. In addition, this group had a higher incidence of elevated serum alanine aminotransferase (ALT), a higher rate of elevated serum aspartate aminotransferase (AST), elevated serum myoglobin, lactate dehydrogenase (LDH), blood urea nitrogen (BUN), and decreased estimated glomerular filtration rate (eGFR) than URNA patients.

Hence, multiple vital organs were more severely affected in URNA+ patients. This group also showed markedly lower levels of T cells and T helper (Th) cells in peripheral blood mononuclear cells. The results showed a correlation of the urinary SARS-CoV-2 RNA with the severity of COVID-19 and the underlying conditions in COVID-19 patients.

Of the 23 patients with severe disease, 12 were urinary SARS-CoV-2 negative (SURNA), and 11 of them were URNA+ (SURNA+). The positive percentage of SARS-CoV-2 RNA in urine was significantly higher in severe patients than in non-severe patients. Thus, SARS-CoV-2 urine loss correlated with disease severity.

It was also found that SURNA+ patients had more comorbidities. This group also had significantly higher levels of IgE and IgG than SURNA patients, along with a higher risk of death than the severe patients with URNA.

In addition, the expression of thrombomodulin (TM) and von Willebrand factor (vWF) in interstitial blood vessels, glomerular and tubules was higher in kidneys of deceased COVID-19 patients compared to that in kidneys of patients with renal carcinoma.

Relevance of the study

The findings of this study indicated that the positivity of SARS-CoV-2 RNA in urine samples can be used to predict the progression and prognosis of COVID-19. The detected positivity rate was 28.3%, which is higher than the test results from routine testing of urine samples.

Therefore, the optimized urine SARS-CoV-2 RNA testing method used in this study could improve the positive rate, which may help predict disease outcome, especially in severe patients. Meanwhile, recovering patients have a limited chance of spreading the virus through their urine.

In addition, the results underlined a possible association of vascular endothelial damage with virus excretion in urine. Therefore, detecting SARS-CoV-2 RNA in urine sediments may be a potential biomarker for evaluation and prognosis for patients with COVID-19.

Reference magazine:

  • Zhang, L., Tian, ​​M., Song, Y., et al. (2021), “Urine SARS-CoV-2 RNA is an indicator of the progression and prognosis of COVID-19”, Diagnostics, 11(11), 2089, doi: 10.3390/diagnostics11112089, https://www.mdpi.com/2075-4418/11/11/2089/htm