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Updated: Jul 16, 2026

Dynamic Monitoring of Seroconversion using a Multianalyte Immunobead Assay for Covid-19
Published on: February 16, 2022
Using patient-collected clinical samples and sera to detect and quantify the severe acute respiratory syndrome
Zhongping He1, Hui Zhuang, Chunhui Zhao
1Beijing Ditan Hospital, Beijing, People's Republic of China. zhongpinghe@yahoo.com
Background:
Severe acute respiratory syndrome (SARS) caused a large outbreak of pneumonia in Beijing, China, in 2003. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect and quantify SARS-CoV in 934 sera and self-collected throat washes and fecal samples from 271 patients with laboratory-confirmed SARS managed at a single institution.
Results:
SARS-CoV detection rates in sera were highest in the first 9 days of illness, whereas detection was highest in throat washes 5-14 days after onset of symptoms. The highest SARS-CoV RT-PCR rates (70.4-86.3%) and viral loads (log10 4.5-6.1) were seen in fecal samples collected 2-4 weeks after the onset of clinical illness. Fecal samples were frequently SARS-CoV RT-PCR positive beyond 40 days, and occasional sera still had SARS-CoV detected after 3 weeks of illness.
Conclusion:
In the context of an extensive outbreak with major pressure on hospital resources, patient self-collected samples are an alternative to nasopharyngeal aspirates for laboratory confirmation of SARS-CoV infection.
