In a study published in the Lancet eBioMedicine Journal, a blood test conducted at the time of COVID-19 infection can predict whether a person is likely to develop long-term COVID or not. In the study, proteins in the blood samples of healthcare workers who tested positive for COVID infection were compared with samples collected from healthcare workers who had not been infected. Based on the comparison between the protein profiles, the researchers found a significant difference in the levels of certain proteins up to six weeks following the infection.

Dr. Gaby Captur, of UCL, stated that the study shows that mild or asymptomatic COVID-19 infection disrupts the protein profile of the infected person. Hence, it can be concluded that even mild COVID infections severely impact normal biological processes of the body.

The researchers analyzed blood plasma samples from 54 healthcare workers in the study. They found that 12 proteins were present at abnormally high levels among the infected individuals. They correlated the degree of abnormality with the severity of the symptoms and revealed that the abnormal levels of 20 select proteins studied in the trial were predictive of persistent symptoms after one year. They also added that these proteins were linked to anticoagulant and anti-inflammatory processes. 

(Source: https://www.tribuneindia.com/news/health/blood-tests-might-help-to-detect-long-covid-in-patients-says-study-437472 )