Characteristics and usefulness of transabdominal ultrasonography in immune-mediated colitis

Background/Aims@#The usefulness of ultrasonography (US) in diseases of the gastrointestinal tract has been reported recently. This prospective study aimed to determine the features of US findings in immune-mediated colitis (IMC), an adverse event induced by immune checkpoint inhibitor, and examine the correlation between US findings, colonoscopy (CS) findings, and severity of colitis. @*Methods@#We studied patients examined using CS and US upon suspicion of IMC in Hokkaido University Hospital between April 2018 and February 2021. Endoscopic findings of IMC were assessed using the Ulcerative Colitis Endoscopic Index of Severity (UCEIS). The severity of US findings in IMC was evaluated using US grade, which is the ultrasonographic grading scale in ulcerative colitis. Bowel wall thickness and the intensity of the color Doppler signal were also analyzed. Severity of colitis was evaluated using Common Terminology Criteria for Adverse Events (CTCAE) grade version 5. @*Results@#Fourteen patients with IMC were enrolled. The US findings were bowel wall thickening, loss of stratification, ulceration and increased blood flow signal. The US grade was moderately correlated with the UCEIS (r=0.687, p=0.009) and CTCAE grade (r=0.628, p=0.035). Bowel wall thickness and UCEIS (r=0.628, p=0.020), as well as color Doppler signal grade and CTCAE grade (r=0.724, p=0.008), were significantly correlated. @*Conclusions@#US findings in IMC were mainly similar to those of ulcerative colitis, but there were some findings that were characteristic only of IMC. Significant correlation was found between US findings, CS findings, and severity of colitis. Hence, US could be useful for the evaluation of IMC.

Performance of qualitative and quantitative antigen tests for SARS-CoV-2 in early symptomatic patients using saliva

BackgroundThe rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an urgent need for the prevention and containment of disease outbreaks in communities. Although the gold standard is polymerase chain reaction (PCR), antigen tests such as immunochromatographic assay (ICA) and chemiluminescent enzyme immunoassay (CLEIA) that can yield results within 30 minutes. MethodsWe evaluated performance of ICA and CLEIA using 34 frozen PCR-positive specimens (17 saliva and 17 nasopharyngeal swab) and 307 PCR-negative samples. ResultsICA detected SARS-CoV-2 in only 14 (41%) samples, with positivity of 24% in saliva and 59% in NPS. Notably, ICA detected SARS-CoV-2 in 5 (83%) of 6 samples collected within 4 days after symptom onset. CLEIA detected SARS-CoV-2 in 31 (91%) samples, with positivity of 82% in saliva and 100% in NPS. CLEIA was negative in 3 samples with low viral load by PCR. ConclusionsThese results suggest that use of ICA should be limited to earlier time after symptom onset and CLEIA is more sensitive and can be used in situations where quick results are required.

Equivalent SARS-CoV-2 viral loads between nasopharyngeal swab and saliva in symptomatic patients

COVID-19 is diagnosed by detecting SARS-CoV-2 by nasopharyngeal swab (NPS) using real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Emerging evidences have shown the utility of saliva, although conflicting results have been reported regarding viral loads between NPS and saliva. We conducted a study to compare the viral loads in 42 patients with COVID-19. Both NPS and saliva specimens were simultaneously obtained at a median of 6 days (range, 1-12) after symptom onset. SARS-CoV-2 was detected in 34 (81%) using NPS (median Ct value [IQR]=27.4 [21.3, 35.6]) and 38 (90%) using saliva (median Ct value [IQR]= 28.9 [23.1, 33.6]). There was no significance difference between them (Wilcoxon signed rank test: P=0.79) and Kendalls W was 0.82, showing a high degree of agreement, indicating equivalent viral loads in NPS and saliva. After symptom onset, the Ct values of both NPS and saliva continued to increase over time, with no substantial difference. Self-collected saliva has a detection sensitivity comparable to that of NPS and is a useful diagnostic tool with mitigating uncomfortable process and the risk of aerosol transmission to healthcare workers.

Mass screening of asymptomatic persons for SARS-CoV-2 using saliva

BackgroundCOVID-19 has rapidly evolved to become a global pandemic due largely to the transmission of its causative virus through asymptomatic carriers. Detection of SARS-CoV-2 in asymptomatic people is an urgent priority for the prevention and containment of disease outbreaks in communities. However, few data are available in asymptomatic persons regarding the accuracy of PCR testing. Additionally, although self-collected saliva has significant logistical advantages in mass screening, its utility as an alternative specimen in asymptomatic persons is yet to be determined. MethodsWe conducted a mass-screening study to compare the utility of nucleic acid amplification, such as reverse transcriptase polymerase chain reaction (RT-PCR) testing, using NPS and saliva samples from each individual in two cohorts of asymptomatic persons: the contact tracing cohort and the airport quarantine cohort. ResultsIn this mass-screening study including 1,924 individuals, the sensitivity of nucleic acid amplification testing with nasopharyngeal and saliva specimens were 86% (90%CI:77-93%) and 92% (90%CI:83-97%), respectively, with specificities greater than 99.9%. The true concordance probability between the nasopharyngeal and saliva tests was estimated at 0.998 (90%CI:0.996-0.999) on the estimated airport prevalence, 0.3%. In positive individuals, viral load was highly correlated between NPS and saliva. ConclusionBoth nasopharyngeal and saliva specimens had high sensitivity and specificity. Self-collected saliva is a valuable specimen to detect SARS-CoV-2 in mass screening of asymptomatic persons.

Efficacy of a novel SARS-CoV-2 detection kit without RNA extraction and purification

Rapid detection of SARS-CoV-2 is critical for the diagnosis of coronavirus disease 2019 (COVID-19) and preventing the spread of the virus. A novel "2019 Novel Coronavirus Detection Kit (nCoV-DK)" halves detection time by eliminating the steps of RNA extraction and purification. We evaluated concordance between the nCoV-DK and direct PCR. The virus was detected in 53/71 fresh samples by the direct method and 55/71 corresponding frozen samples by the nCoV-DK. The overall concordance rate of the virus detection between the two methods was 94.4% (95% CI, 86.2-98.4). Concordance rates were 95.2% (95% CI, 83.8-99.4), 95.5% (95% CI, 77.2-99.9), 85.7% (95% CI, 42.1-99.6) in nasopharyngeal swab, saliva, and sputum samples, respectively. These results indicate that the nCoV-DK effectively detects SARS-CoV-2 in all types of the samples including saliva, while reducing time required for detection, labor, and risk of human error.

Older age is associated with sustained detection of SARS-CoV-2 in nasopharyngeal swab samples

PCR testing of nasopharyngeal swab samples is used for the diagnosis of coronavirus disease 2019 (COVID-19) and for determining timing of discharge. The viral load usually declines at convalescent phase, but sometimes remained positive for a long time even after relief of symptoms. In this study, we identified older age is associated with sustained detection of SARS-CoV-2 in nasopharyngeal swab samples.

Comparison of SARS-CoV-2 detection in nasopharyngeal swab and saliva

We prospectively compared the efficacy of PCR detection of SARS-CoV-2 between paired nasopharyngeal and saliva samples in nine COVID-19 patients. SARS-CoV-2 was detected in saliva in 8 of 9 (89%) patients and in all 11 samples taken within 2 weeks after disease onset. Viral load was equivalent at earlier time points but declined in saliva than nasopharyngeal samples. PCR negativity was also concordant in all 27 saliva samples from 24 patients between nasopharyngeal and saliva samples. These results suggest that saliva is a reliable noninvasive alternative to nasopharyngeal swabs and facilitate widespread PCR testing in the face of shortages of swabs and protective equipment without posing a risk to healthcare workers.