Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Positive rates of NP-IgA ELISA for detection of the sequential samples of 28 COVID-19 patients with different disease courses from the symptom onset. Sequential samples include serum, throat swabs, and sputum from all phases of the disease. **p < 0.01, ***p < 0.001 (compared with positive rates of serum, two-tailed Fisher’s exact test).
