{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T16:28:51Z","timestamp":1786120131450,"version":"build-2736575974"},"reference-count":12,"publisher":"Oxford University Press (OUP)","issue":"Supplement_1","funder":[{"DOI":"10.13039\/100007680","name":"Naval Medical Research Command","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100007680","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,8,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). Studies have shown the association of viral RNAemia with the severity of COVID-19 and poor patient outcomes. Here, we compared 2 reverse transcription PCR assays: droplet digital PCR (ddPCR) and quantitative PCR (qPCR), in determining the viral RNA copy numbers in patient plasma.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Material and Methods<\/jats:title>\n                    <jats:p>A total of 229 plasma samples collected on days 0, 1, 4, 7, and 28 (when available) from 33 COVID-19 ICU patients were analyzed. RNA was extracted from samples using the MagNA Pure 96 DNA and Viral NA small volume kit (Roche Diagnostic) on the MagNA Pure 96 platform with 100 mL starting and elution volumes. For ddPCR, the quantification of viral RNA copies was performed using a SARS-CoV-2 ddPCR kit (Bio-Rad Laboratories Inc.) following the manufacturer\u2019s instruction. For qPCR, the quantification of viral RNA copies was determined using the CDC 2019-Novel Coronavirus real-time RT-PCR diagnostic panel on an Applied Biosystems 7500 Fast Dx real-time PCR system with a set of known copy-positive controls as standard.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Our results showed that not all patients had detectable viral RNA in their plasma samples by both methods, with only 23 (70%) and 31 (94%) patients having detectable viral RNA by ddPCR and qPCR, respectively. The qPCR detected viral RNA amplicons of both N1 and N2 targets in 87 specimens, and when these N1 and N2 copy numbers were averaged, the median was 447.7 copies\/mL of plasma with a range of 56.8 to 192,495.5 copies\/mL of plasma. The ddPCR detected viral RNA amplicons in 64 specimens, the median was 173.4 copies\/mL of plasma with a range of 39.7-108,326.6 copies\/mL of plasma when the N1 and N2 copy numbers were averaged.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Both ddPCR and qPCR methods can detect viral RNA in plasma samples from severe COVID-19 patients. The qPCR was able to detect more positive specimens, suggesting higher sensitivity compared to the ddPCR method.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/milmed\/usag116","type":"journal-article","created":{"date-parts":[[2026,3,3]],"date-time":"2026-03-03T12:37:13Z","timestamp":1772541433000},"page":"425-428","source":"Crossref","is-referenced-by-count":0,"title":["Comparison Between Reverse Transcription Droplet Digital and Quantitative Polymerase Chain Reactions for the Determination of Viral RNA Copy Numbers in COVID-19 Patient Plasma"],"prefix":"10.1093","volume":"191","author":[{"given":"Hua-Wei","family":"Chen","sequence":"first","affiliation":[{"name":"Naval Medical Research Command , Silver Spring, MD 20910,","place":["United States"]},{"name":"Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD 20817,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Victor A","family":"Sugiharto","sequence":"additional","affiliation":[{"name":"Naval Medical Research Command , Silver Spring, MD 20910,","place":["United States"]},{"name":"Henry M. Jackson Foundation for the Advancement of Military Medicine , Bethesda, MD 20817,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark P","family":"Simons","sequence":"additional","affiliation":[{"name":"Naval Medical Research Command , Silver Spring, MD 20910,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah A","family":"Jenkins","sequence":"additional","affiliation":[{"name":"Uniformed Services University of the Health Sciences , Bethesda, MD 20814,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,8,6]]},"reference":[{"key":"2026080616024389000_usag116-B1"},{"key":"2026080616024389000_usag116-B2","doi-asserted-by":"publisher","first-page":"e0254640","DOI":"10.1371\/journal.pone.0254640","article-title":"On-admission SARS-CoV-2 RNAemia as a single potent predictive marker of critical condition development and mortality in COVID-19","volume":"16","author":"Miki","year":"2021","journal-title":"PLoS One"},{"key":"2026080616024389000_usag116-B3","doi-asserted-by":"publisher","first-page":"465","DOI":"10.1038\/s41586-020-2196-x","article-title":"Virological assessment of hospitalized patients with COVID-2019","volume":"581","author":"Wolfel","year":"2020","journal-title":"Nature"},{"key":"2026080616024389000_usag116-B4","doi-asserted-by":"publisher","first-page":"1843","DOI":"10.1001\/jama.2020.3786","article-title":"Detection of SARS-CoV-2 in different types of clinical specimens","volume":"323","author":"Wang","year":"2020","journal-title":"JAMA"},{"key":"2026080616024389000_usag116-B5","doi-asserted-by":"publisher","first-page":"5493","DOI":"10.1038\/s41467-020-19057-5","article-title":"SARS-CoV-2 viral load is associated with increased disease severity and mortality","volume":"11","author":"Fajnzylber","year":"2020","journal-title":"Nat Commun"},{"key":"2026080616024389000_usag116-B6","doi-asserted-by":"publisher","first-page":"e291","DOI":"10.1093\/cid\/ciaa1054","article-title":"High frequency of SARS-CoV-2 RNAemia and association with severe disease","volume":"72","author":"Hogan","year":"2021","journal-title":"Clin Infect Dis"},{"key":"2026080616024389000_usag116-B7","doi-asserted-by":"publisher","first-page":"218","DOI":"10.1093\/cid\/ciab394","article-title":"SARS-CoV-2 RNAemia predicts clinical deterioration and extrapulmonary complications from COVID-19","volume":"74","author":"Ram-Mohan","year":"2022","journal-title":"Clinical Infectious Diseases"},{"key":"2026080616024389000_usag116-B8","doi-asserted-by":"publisher","first-page":"1525","DOI":"10.1093\/cid\/ciab686","article-title":"Severe acute respiratory syndrome coronavirus 2 viremia is associated with coronavirus disease 2019 severity and predicts clinical outcomes","volume":"74","author":"Jacobs","year":"2022","journal-title":"Clin Infect Dis"},{"key":"2026080616024389000_usag116-B9","doi-asserted-by":"publisher","first-page":"5203","DOI":"10.1128\/AEM.00931-15","article-title":"Comparison of quantitative PCR and droplet digital PCR multiplex assays for two genera of bloom-forming cyanobacteria, cylindrospermopsis and microcystis","volume":"81","author":"Te","year":"2015","journal-title":"Appl Environ Microbiol."},{"key":"2026080616024389000_usag116-B10","doi-asserted-by":"publisher","first-page":"115677","DOI":"10.1016\/j.diagmicrobio.2022.115677","article-title":"Comparison of reverse-transcription qPCR and droplet digital PCR for the detection of SARS-CoV-2 in clinical specimens of hospitalized patients","volume":"103","author":"Li","year":"2022","journal-title":"Diagn Microbiol Infect Dis"},{"key":"2026080616024389000_usag116-B11","doi-asserted-by":"publisher","first-page":"114829","DOI":"10.1016\/j.marpolbul.2023.114829","article-title":"Comparison between droplet digital PCR and reverse transcription-quantitative PCR methods to measure ecotoxicology biomarkers","volume":"190","author":"Baettig","year":"2023","journal-title":"Mar Pollut Bull"},{"key":"2026080616024389000_usag116-B12","doi-asserted-by":"publisher","first-page":"100967","DOI":"10.1016\/j.lanmic.2024.100967","article-title":"Prevalence and clinical relevance of viraemia in viral respiratory tract infections: a systematic review","volume":"6","author":"Hagman","year":"2025","journal-title":"Lancet Microbe"}],"container-title":["Military 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