Blood testing may aid in detection of long covid in patients: Research

A blood test performed at the time of Covid-19 infection, according to studies, can help determine whether a person is likely to develop long-term Covid.

The study, published in the journal Lancet eBioMedicine, examined proteins in the blood of healthcare workers infected with SARS-CoV-2 and compared them to samples from uninfected healthcare workers. Protein levels in the body are usually steady. However, the researchers discovered a significant variation in the levels of several of the proteins up to six weeks after infection, suggesting that a number of critical biological processes were disrupted.

They established a “signature” in the amount of several proteins using an artificial intelligence (AI) algorithm that correctly predicted whether or not the person would go on to report persistent symptoms a year after infection.

According to the researchers, if these findings are replicated in a larger, independent group of patients, a test that predicts the chance of getting long Covid might possibly be administered alongside a polymerase chain reaction (PCR) test.

“Human work reveals that even modest or asymptomatic Covid-19 affects the composition of proteins in our blood plasma,” stated lead author Dr Gaby Captur (MRC Unit for Lifelong Health and Ageing at UCL).

This suggests that even modest Covid-19 has a profound effect on normal biological processes for at least six weeks following infection.

“Our technique for predicting long Covid has to be verified with a broader, independent sample of patients. Using our technique, however, a test that predicts long Covid at the time of first infection might be swiftly and cost-effectively implemented.

“The technology we chose is widely available in hospitals and has a high throughput, which means it can analyse hundreds of samples in an afternoon.”

“If we can identify people who are likely to develop long Covid, this opens the door to trialling treatments such as anti-virals at this earlier, initial infection stage, to see if it can reduce the risk of later long Covid,” said senior author Dr Wendy Heywood (UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital).

Researchers compared blood plasma samples obtained every week for six weeks in spring 2020 from 54 healthcare workers who had PCR, or antibody-confirmed infection, to samples taken during the same period from 102 healthcare workers who were not sick.

They examined how Covid-19 altered these proteins over the course of six weeks using targeted mass spectrometry, a type of study that is particularly sensitive to small changes in the amount of proteins in blood plasma.

The researchers discovered unusually high amounts of 12 proteins out of the 91 examined in SARS-CoV-2 patients, and the degree of abnormality correlated with the severity of symptoms.

The researchers discovered that aberrant levels of 20 proteins tested at the time of the first infection predicted persisting symptoms after a year. The majority of these proteins were shown to be involved in anti-coagulant (anti-clotting) and anti-inflammatory actions.

Also read: Know what connects human senses and thinking

A machine learning system based on the participants’ protein profiles was able to differentiate all 11 infected healthcare professionals who reported at least one persistent symptom after a year from infected healthcare workers who did not report persistent symptoms after a year. Another machine learning technique was employed to predict the chance of mistake, and it estimated that this strategy may have a 6% error rate.

Follow Medically Speaking on Twitter Instagram Facebook