COVID-19 screening test by using random oropharyngeal saliva.

An optimal clinical specimen for accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by minimizing the usage of consumables and reduce hazard exposure to healthcare workers is an urgent priority. The diagnostic performance of SARS-CoV-2 detection between healthcare worker-collected nasopharyngeal and oropharyngeal (NP + OP) swabs and patient performed self-collected random saliva was assessed. Paired NP + OP swabs and random saliva were collected and processed within 48 h of specimen collection from two cohort studies which recruited 562 asymptomatic adult candidates. Real-time reverse-transcription polymerase chain reaction targeting Open reading frame 1a (ORF1a) and nucleocapsid (N) genes was performed and the results were compared. Overall, 65 of 562 (28.1%) candidates tested positive for COVID-19 based on random saliva, NP + OP swabs, or both testing techniques. The detection rate of SARS-CoV-2 was higher in random saliva compared to NP + OP testing (92.3%; 60/65 vs. 73.8%; 48/65; p < .05). The estimated sensitivity and specificity of random saliva were higher than NP + OP swabs (95.0; 99.9 vs. 72.2; 99.4). The Ct  values of ORF1a and N genes were significantly lower in random saliva compared to NP + OP swabs specimens. Our findings demonstrate that random saliva is an alternative diagnostic specimen for the detection of SARS-CoV-2. Self-collected random oropharyngeal saliva is a valuable specimen that provides accurate SARS-CoV-2 surveillance testing of a community.

Rao M ，Rashid FA ，Sabri FSAH ，Jamil NN ，Seradja V ，Abdullah NA ，Ahmad H ，Aren SL ，Ali SAS ，Ghazali M ，Manaf AA ，Talib H ，Hashim R ，Zain R ，Thayan R ，Amran F ，Aris T ，Ahmad N ... -  《-》

Performance of Saliva, Oropharyngeal Swabs, and Nasal Swabs for SARS-CoV-2 Molecular Detection: a Systematic Review and Meta-analysis.

Nasopharyngeal (NP) swabs are considered the highest-yield sample for diagnostic testing for respiratory viruses, including SARS-CoV-2. The need to increase capacity for SARS-CoV-2 testing in a variety of settings, combined with shortages of sample collection supplies, have motivated a search for alternative sample types with high sensitivity. We systematically reviewed the literature to understand the performance of alternative sample types compared to NP swabs. We systematically searched PubMed, Google Scholar, medRxiv, and bioRxiv (last retrieval 1 October 2020) for comparative studies of alternative specimen types (saliva, oropharyngeal [OP], and nasal [NS] swabs) versus NP swabs for SARS-CoV-2 diagnosis using nucleic acid amplification testing (NAAT). A logistic-normal random-effects meta-analysis was performed to calculate % positive alternative-specimen, % positive NP, and % dual positives overall and in subgroups. The QUADAS 2 tool was used to assess bias. From 1,253 unique citations, we identified 25 saliva, 11 NS, 6 OP, and 4 OP/NS studies meeting inclusion criteria. Three specimen types captured lower % positives (NS [82%, 95% CI: 73 to 90%], OP [84%, 95% CI: 57 to 100%], and saliva [88%, 95% CI: 81 to 93%]) than NP swabs, while combined OP/NS matched NP performance (97%, 95% CI: 90 to 100%). Absence of RNA extraction (saliva) and utilization of a more sensitive NAAT (NS) substantially decreased alternative-specimen yield of positive samples. NP swabs remain the gold standard for diagnosis of SARS-CoV-2, although alternative specimens are promising. Much remains unknown about the impact of variations in specimen collection, processing protocols, and population (pediatric versus adult, late versus early in disease course), such that head-to head studies of sampling strategies are urgently needed.

Lee RA ，Herigon JC ，Benedetti A ，Pollock NR ，Denkinger CM ... -  《-》

Diagnostic Performance of Self-Collected Saliva Versus Nasopharyngeal Swab for the Molecular Detection of SARS-CoV-2 in the Clinical Setting.

Uddin MKM ，Shirin T ，Hossain ME ，Alam AN ，Ami JQ ，Hasan R ，Miah M ，Shaly NJ ，Ahmed S ，Rahman SMM ，Rahman M ，Banu S ... -  《Microbiology Spectrum》

A Multiplex One-Step RT-qPCR Protocol to Detect SARS-CoV-2 in NP/OP Swabs and Saliva.

Since December 2019, SARS-CoV-2 has spread extensively throughout the world, with more than 117 million reported cases and 2.6 million deaths (Johns Hopkins coronavirus resource center, https://coronavirus.jhu.edu/map.html). Detecting the virus is the first step in diagnosing the infection, followed by quarantine to prevent transmission. Nasopharyngeal/oropharyngeal swabs (NP/OP) and saliva are two specimen types that are most often analyzed to detect SARS-CoV-2 by molecular tests that detect viral RNA or by antigen/antibody tests that detect viral proteins and/or the host immune response against the virus. Compared to antigen/antibody tests, molecular tests are highly sensitive and specific for detecting the virus. A significant drawback is that specimen collection requirements are specific to each test and cannot be interchanged with another test. Some tests are qualified to be used on NP swabs or saliva, but not both specimen types. Even with NP swabs, a test may be qualified to detect the virus only with swabs collected in viral transport medium (VTM) but not in other media. These restrictive pre-analytic steps are disadvantageous in that a lab would have to develop and validate different tests for SARS-CoV-2 depending on the specimen type and collection media, with added setup cost, infrastructure, and training requirements. To overcome these problems, we developed and validated a cost-effective multiplex reverse-transcription real-time PCR assay that can be used to detect SARS-CoV-2 in different specimen types. The assay is highly sensitive and specific, can be used to detect the virus in saliva as well as NP swabs collected in different media such as VTM, saline, and commercial preservative fluid, and serves as one test for all applications. The protocol also describes an optimal laboratory setup and unidirectional workflow for detecting SARS-CoV-2 by RT-qPCR. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Manual viral nucleic acid extraction from NP/OP swabs collected in different media, and from saliva Alternate Protocol 1: Low-throughput automated extraction on the Qiagen EZ1 Advanced XL machine (1-14 samples) Alternate Protocol 2: High-throughput automated extraction on the Kingfisher Flex machine (1-96 samples) Basic Protocol 2: Multiplex RT-qPCR protocol to detect SARS-CoV-2 Alternate Protocol 3: Multiplex one-step RT-qPCR protocol to detect SARS-CoV-2 with S and E gene probes labeled with the same fluorochrome.

Bland J ，Kavanaugh A ，Hong LK ，Perez O ，Kadkol SS ... -  《-》

Reliable detection of SARS-CoV-2 with patient-collected swabs and saline gargles: A three-headed comparison on multiple molecular platforms.

With increasing demands for SARS-CoV-2 testing, as well as the shortages for testing supplies, collection devices, and trained healthcare workers (HCWs) to collect specimens, self-collection is an attractive prospect to reduce the need for HCWs and expenditure of personal protective equipment. Apart from the traditional nasopharyngeal swab used for SARS-CoV-2 detection, alternative specimens have been validated such as a combined swabs of the oropharynx and anterior nares (OP/N), or throat samples using saline gargles. Both the alternative specimen types are amenable to self-collection. Objectives. This study aimed to compare the sensitivity of HCW-collected (OP/N) swabs, self-collected OP/N swabs, and self-collected saline gargles. Among 38 individuals previously testing positive for SARS-CoV-2 (or their close contacts), two self-collected specimen types (OP/N and saline gargles) were compared to HCW-collected OP/N swabs. SARS-CoV-2 testing was performed on three molecular assays: a laboratory-developed test (LDT), and two commercial assays on automated platforms: Cobas 6800 (Roche Diagnostics) and Panther (Hologic). The sensitivity of self-collected OP/N swabs was equivalent to healthcare worker (HCW)-collected OP/N swabs at 100.0 % [92.6%-100.0%] for all three molecular tests. The sensitivity of saline gargles was not significantly different than HCW-collected OP/N swabs, but varied slightly between instruments at 93.8 % [85.9%-93.8%] for the LDT, 96.8 % [88.6%-96.8%] for the Cobas assay, and 96.7 % [89.2%-96.9%] for the Panther assay. Overall, self-collection using OP/N swabs or saline gargles are reasonable alternatives to HCW-based collections for SARS-CoV-2 detection, and could facilitate broader surveillance strategies.

LeBlanc JJ ，Pettipas J ，Di Quinzio M ，Hatchette TF ，Patriquin G ... -  《-》