Analysis of factors associated early diagnosis in coronavirus disease 2019 (COVID-19)

Jinwei Ai; Junyan Gong; Limin Xing; Renjiao He; Fangtao Tian; Juan Wang; Jun Wang; Shengduo Polo Pei; Dongxuan Chen; Guoxin Huang; Meiling Zhang; Gaojing Qu; Wufeng Fan; Hongming Lin; Desheng Li; Bin Pei

Previous research (14) shows the main reasons of nucleic acid RT-PCR test's false negative result are: 1) Lack of standardized operating procedures for specimen collection, storage and processing in clinical work; 2) Different viral loads at different disease stages of COVID-19 have certain effects on nucleic acid RT-PCR test; 3) Lack of calibration test for current nucleic acid RT-PCR test; 4) SARS-CoV-2 may have relatively high mutation rate. Nucleic acid RT-PCR test is the diagnosis basis of confirming COVID-19, but the first-time test has relatively high false negative rate. Diagnosing suspected cases before they are test confirmed can only rely on patient's clinical characteristics, chest CT imaging features and laboratory test results. Therefore, this study's conclusion provides a reliable theoretical basis for the clinical diagnosis of COVID-19. Respiratory infection symptoms such as fever and cough, typical chest CT imaging features, middle aged and elderly patients (age > 41.5 years), lymphocyte count lower than 1.53×10 9 /L should be considered linked to COVID-19. If there is available travel history in epidemic area or contact history with people form epidemic area or with confirmed patients, that could provide another strong evidence for diagnosing COVID-19. For these patients, isolation and medical treatment should be carried out as early as possible, which would be helpful for better control of the infection and cut off the transmission at an early stage. Moreover, this study's first-time nucleic acid RT-PCR tests have a test positive rate of 68%, which is higher than previous study (14, 16) (positive rate 30-50%). It may be related to the fact that the nucleic acid test samples were collected and stored by specialized personnel in our hospital who had received professional training. Which indicates that nucleic acid test in strict accordance with operating procedures, careful sample storage and transfer procedures can increase the positive rate of first-time nucleic acid test, All rights reserved. No reuse allowed without permission. the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.