• Clinical Validation of a Sensitive Test for Saliva Collected in Healthcare and Community Settings with Pooling Utility for Severe Acute Respiratory Syndrome Coronavirus 2 Mass Surveillance

      Sahajpal, Nikhil S.; Mondal, Ashis K.; Ananth, Sudha; Njau, Allan; Ahluwalia, Pankaj; Kota, Vamsi; Caspary, Kevin; Ross, Ted M.; Farrell, Michael; Shannon, Michael P.; et al. (Elsevier, 2021-07)
      The clinical performance of saliva compared with nasopharyngeal swabs (NPSs) has shown conflicting results in healthcare and community settings. In the present study, a total of 429 matched NPS and saliva sample pairs, collected in either healthcare or community setting, were evaluated. Phase-1 (protocol U) tested 240 matched NPS and saliva sample pairs; phase 2 (SalivaAll protocol) tested 189 matched NPS and saliva sample pairs, with an additional sample homogenization step before RNA extraction. A total of 85 saliva samples were evaluated with both protocols. In phase-1, 28.3% (68/ 240) samples tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from saliva, NPS, or both. The detection rate from saliva was lower compared with that from NPS samples (50.0% versus 89.7%). In phase-2, 50.2% (95/189) samples tested positive for SARS-CoV-2 from saliva, NPS, or both. The detection rate from saliva was higher compared with that from NPS samples (97.8% versus 78.9%). Of the 85 saliva samples evaluated with both protocols, the detection rate was 100% for samples tested with SalivaAll, and 36.7% with protocol U. The limit of detection with SalivaAll protocol was 20 to 60 copies/mL. The pooled testing approach demonstrated a 95% positive and 100% negative percentage agreement. This protocol for saliva samples results in higher sensitivity compared with NPS samples and breaks the barrier to using pooled saliva for SARS-CoV-2 testing.
    • Clinical validation of innovative, low cost, kit-free, RNA processing protocol for RT-PCR based COVID-19 testing

      Sahajpal, Nikhil Shri; Mondal, Ashis K; Njau, Allan; Ananth, Sudha; Kothandaraman, Arvind; Hegde, Madhuri; Chaubey, Alka; Padala, Sandeep; Kota, Vamsi; Caspary, Kevin; et al. (medRxiv, 2020-07-30)
      The current gold-standard molecular diagnosis for COVID-19 is based on a multi-step assay involving RNA-extraction and RT-PCR analysis for the detection of SARS-CoV-2. RNA34 extraction step has been a major rate-limiting step in implementing high-throughput screening for COVID-19 during this pandemic. Moreover, clinical laboratories are facing several challenges that include cost, reagents, instrumentation, turn-around time, trained personnel, and supply-chain constraints to efficiently implement and sustain testing. Cognizant of these limitations, we evaluated the extraction-free methods described in the literature and have developed an innovative, simplified and easy protocol employing limited reagents to extract RNA for subsequent RT-PCR analysis. Nasopharyngeal-swab samples were subjected to the following individual conditions: 65°C for 15 minutes; 80°C for 5 minutes; 90°C for 5 minutes or 80°C for 1 minute, and processed for direct RT-PCR. These groups were also compared with a supplemental protocol adding isopropanol-ethanol-water elution steps followed by RT-PCR assay. The direct RT-PCR assay did not detect SARS-CoV-2 within the various temperature incubation only groups, whereas, the 90°C for 5 minutes-isopropanol-ethanol-water method was found to be comparable to the FDA-EUA method. Evaluation of the performance metrics for 100 clinical samples demonstrated a sensitivity of 94.2% and a specificity of 100%. The limit of detection was ascertained to be ~40 copies/ml by absolute-quantification. The protocol presented for this assay employs limited reagents and yields results with high sensitivity. Additionally, it presents a simplified methodology that would be easier to implement in laboratories in limited resource countries in order to meet the high current COVID-19 testing needs.
    • High-Throughput Next-Generation Sequencing Respiratory Viral Panel: A Diagnostic and Epidemiologic Tool for SARS-CoV-2 and Other Viruses

      Sahajpal, Nikhil S.; Mondal, Ashis K.; Njau, Allan; Petty, Zachary; Chen, Jiani; Ananth, Sudha; Ahluwalia, Pankaj; Williams, Colin; Ross, Ted M.; Chaubey, Alka; et al. (MDPI, 2021-10-14)
      Two serious public health challenges have emerged in the current COVID-19 pandemic namely, deficits in SARS-CoV-2 variant monitoring and neglect of other co-circulating respiratory viruses. Additionally, accurate assessment of the evolution, extent, and dynamics of the outbreak is required to understand the transmission of the virus. To address these challenges, we evaluated 533 samples using a high-throughput next-generation sequencing (NGS) respiratory viral panel (RVP) that includes 40 viral pathogens. The performance metrics revealed a PPA, NPA, and accuracy of 95.98%, 85.96%, and 94.4%, respectively. The clade for pangolin lineage B that contains certain distant variants, including P4715L in ORF1ab, Q57H in ORF3a, and S84L in ORF8 covarying with the D614G spike protein mutation, were the most prevalent early in the pandemic in Georgia, USA. The isolates from the same county formed paraphyletic groups, indicating virus transmission between counties. The study demonstrates the clinical and public health utility of the NGS-RVP to identify novel variants that can provide actionable information to prevent or mitigate emerging viral threats and models that provide insights into viral transmission patterns and predict transmission/resurgence of regional outbreaks as well as providing critical information on co-circulating respiratory viruses that might be independent factors contributing to the global disease burden.
    • Making a Difference: Adaptation of the Clinical Laboratory in Response to the Rapidly Evolving COVID-19 Pandemic

      Sahajpal, Nikhil S.; Mondal, Ashis K.; Ananth, Sudha; Njau, Allan; Fulzele, Sadanand; Ahaluwalia, Pankaj; Chaubey, Alka; Hegde, Madhuri; Rojiani, Amyn M.; Kolhe, Ravindra; et al. (Sage, 2021-06-29)
      The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, led to unprecedented demands assigned to clinical diagnostic laboratories worldwide, forcing them to make significant changes to their regular workflow as they adapted to new diagnostic tests and sample volumes. Herein, we summarize the modifications/adaptation the laboratory had to exercise to cope with rapidly evolving situations in the current pandemic. In the first phase of the pandemic, the laboratory validated 2 reverse transcription polymerase chain reaction–based assays to test ∼1000 samples/day and rapidly modified procedures and validated various preanalytical and analytical steps to overcome the supply chain constraints that would have otherwise derailed testing efforts. Further, the pooling strategy was validated for wide-scale population screening using nasopharyngeal swab samples and saliva samples. The translational research arm of the laboratory pursued several initiatives to understand the variable clinical manifestations that this virus presented in the population. The phylogenetic evolution of the virus was investigated using next-generation sequencing technology. The laboratory has initiated the formation of a consortium that includes groups investigating genomes at the level of large structural variants, using genome optical mapping via this collaborative global effort. This article summarizes our journey as the laboratory has sought to adapt and continue to positively contribute to the unprecedented demands and challenges of this rapidly evolving pandemic.
    • Next-Generation Sequencing (NGS) in COVID-19: A Tool for SARS-CoV-2 Diagnosis, Monitoring New Strains and Phylodynamic Modeling in Molecular Epidemiology

      John, Goldin; Sahajpal, Nikhil Shri; Mondal, Ashis K.; Ananth, Sudha; Williams, Colin; Chaubey, Alka; Rojiani, Amyn M.; Kolhe, Ravindra; Department of Pathology (MDPI, 2021-07-30)
      This review discusses the current testing methodologies for COVID-19 diagnosis and explores next-generation sequencing (NGS) technology for the detection of SARS-CoV-2 and monitoring phylogenetic evolution in the current COVID-19 pandemic. The review addresses the development, fundamentals, assay quality control and bioinformatics processing of the NGS data. This article provides a comprehensive review of the obstacles and opportunities facing the application of NGS technologies for the diagnosis, surveillance, and study of SARS-CoV-2 and other infectious diseases. Further, we have contemplated the opportunities and challenges inherent in the adoption of NGS technology as a diagnostic test with real-world examples of its utility in the fight against COVID-19.
    • SalivaSTAT: Direct-PCR and Pooling of Saliva Samples Collected in Healthcare and Community Setting for SARS-CoV-2 Mass Surveillance

      Sahajpal, Nikhil S.; Mondal, Ashis K.; Ananth, Sudha; Njau, Allan; Ahluwalia, Pankaj; Newnam, Gary; Lozoya-Colinas, Adriana; Hud, Nicholas V.; Kota, Vamsi; Ross, Ted M.; et al. (MDPI, 2021-05-19)
      Objectives: Limitations of widespread current COVID-19 diagnostic testing exist in both the pre-analytical and analytical stages. To alleviate these limitations, we developed a universal saliva processing protocol (SalivaSTAT) that would enable an extraction-free RT-PCR test using commercially available RT-PCR kits. Methods: We optimized saliva collection devices, heat-shock treatment, and homogenization. Saliva samples (879) previously tested using the FDA-EUA method were reevaluated with the optimized SalivaSTAT protocol using two widely available commercial RT-PCR kits. A five-sample pooling strategy was evaluated as per FDA guidelines. Results: Saliva collection (done without any media) showed performance comparable to that of the FDA-EUA method. The SalivaSTAT protocol was optimized by incubating saliva samples at 95 ◦C for 30-min and homogenization, followed by RT-PCR assay. The clinical sample evaluation of 630 saliva samples using the SalivaSTAT protocol with PerkinElmer (600-samples) and CDC (30-samples) RT-PCR assay achieved positive (PPA) and negative percent agreements (NPAs) of 95.0% and 100%, respectively. The LoD was established as ~60–180 copies/mL by absolute quantification. Furthermore, a five-samplepooling evaluation using 250 saliva samples achieved a PPA and NPA of 92% and 100%, respectively. Conclusion: We have optimized an extraction-free RT-PCR assay for saliva samples that demonstrates comparable performance to FDA-EUA assay (Extraction and RT-PCR).