IMAGE DESCRIPTION: An image of a blood test tube showing plasma. The title reads: Medscape: New Tests May Finally Diagnose Long Covid. The ME Association Logo (bottom right).

Medscape: New Tests May Finally Diagnose Long Covid

One of the biggest challenges facing clinicians who treat long COVID is a lack of consensus when it comes to recognizing and diagnosing the condition.

By Sara Novak


Researchers at Cardiff University School of Medicine in Cardiff, Wales, United Kingdom, tracked 166 patients, 79 of whom had been diagnosed with long COVID and 87 who had not. All participants had recovered from a severe bout of acute COVID-19.

In an analysis of the blood plasma of the study participants, researchers found elevated levels of certain components. Four proteins in particular — Ba, iC3b, C5a, and TCC — predicted the presence of long COVID with 78.5% accuracy.

The study revealed that long COVID was associated with inflammation of the immune system causing these complement proteins to remain dysregulated. Proteins like C3, C4, and C5 are important parts of the immune system because they recruit phagocytes, cells that attack and engulf bacteria and viruses at the site of infection to destroy pathogens like SARS-coV-2. 

The more doctors understand about the mechanism causing immune dysregulation in long COVID patients, the more they can treat it with existing medications. Zelek’s lab has been studying certain medications like pegcetacoplan (C3 blocker), danicopan (anti-factor D), and iptacopan (anti-factor B) that can be used to break the body’s cycle of inflammation and reduce symptoms experienced in those with long COVID. 

MEA Comment

Dr Katrina Pears, Research Correspondent for the ME Association says:

This is an interesting study on finding a biomarker for Long Covid, which is currently published as a preprint. This was a medium-sized study with 166 patients with Long Covid and 79 controls. Although much more replication is needed before the four proteins identified can be used in diagnostic tests, for example, we do not know how these levels will change over time or if they vary with infection by different Covid-19 variants. 

It is a great shame that after comparing Long Covid symptoms to that of ME/CFS in the introduction, there is no mention afterwards. It would be interesting to know how these findings correspond to ME/CFS cohort, and if the four proteins identified are also elevated. I do hope that this research is followed up as this could lead to breakthroughs in diagnosing Long Covid and hopefully advance ME/CFS research too.

Dr Katrina Pears,
Research Correspondent.
The ME Association.

Dr Katrina Pears - MEA Research Correspondent
Shopping Basket