@jeindc, I did see these 2024 research articles on the topic.

"New research published Thursday in Science has identified proteins present in the blood of people with long Covid that could point the way to a much-needed diagnostic test and possibly to future therapeutic targets.
Jan 18, 2024"
--- Could long Covid’s signs of immune dysregulation in the blood lead to a diagnostic test?
https://www.statnews.com/2024/01/18/long-covid-new-research-blood-samples-show-immunity-link/
"What are the inflammatory markers for long COVID patients?
Elevated markers of myeloid inflammation and complement activation were associated with long COVID. IL-1R2, MATN2 and COLEC12 were associated with cardiorespiratory symptoms, fatigue and anxiety/depression; MATN2, CSF3 and C1QA were elevated in gastrointestinal symptoms and C1QA was elevated in cognitive impairment."
--- Large-scale phenotyping of patients with long COVID post-hospitalization reveals mechanistic subtypes of disease: https://www.nature.com/articles/s41590-024-01778-0