RT-PCR
is the primary method to diagnose COVID-19 and is also used
to monitor the disease course. This approach, however, suffers from
false negatives due to RNA instability and poses a high risk to medical
practitioners. Here, we investigated the potential of using serum
proteomics to predict viral nucleic acid positivity during COVID-19.
We analyzed the proteome of 275 inactivated serum samples from 54
out of 144 COVID-19 patients and shortlisted 42 regulated proteins
in the severe group and 12 in the non-severe group. Using these regulated
proteins and several key clinical indexes, including days after symptoms
onset, platelet counts, and magnesium, we developed two machine learning
models to predict nucleic acid positivity, with an AUC of 0.94 in
severe cases and 0.89 in non-severe cases, respectively. Our data
suggest the potential of using a serum protein-based machine learning
model to monitor COVID-19 progression, thus complementing swab RT-PCR
tests. More efforts are required to promote this approach into clinical
practice since mass spectrometry-based protein measurement is not
currently widely accessible in clinic.