Researchers in the UK have identified two blood biomarkers that could serve as early indicators of cognitive deficits in COVID-19 patients. 

Cognitive issues, including the commonly reported 'brain fog', have been a concern in post-COVID-19 patients. 

The study, published in Nature Medicine, drew data from over 1,800 COVID-19 patients hospitalised in the UK between January 2020 and November 2021.

The scientists collected blood samples from these patients during hospitalisation and conducted cognition tests six and twelve months later, encompassing both clinician-based and patient-reported assessments. 

Their statistical analysis revealed two significant biomarker profiles associated with cognitive deficits. 

The first biomarker, fibrinogen, linked strongly to both objective and subjective cognitive problems. 

The second biomarker, d-dimer, correlated with subjective issues such as 'brain fog', fatigue, and shortness of breath. 

These findings were validated in a separate study of 17,911 US patients, confirming the specificity of d-dimer for COVID-19.

While promising, further research is required to develop a diagnostic test for COVID-19-related cognitive problems. 

Nonetheless, these biomarkers provide insight into the development of post-COVID-19 cognitive deficits and may facilitate prognosis and management in the future.

The study is accessible here.