65+ million people worldwide suffer from Long COVID. There is no validated diagnostic. Standard tests return normal while patients remain disabled. Multi-system analysis may succeed where single-system approaches fail.
Single biomarkers fail because Long COVID is a multi-system disease. Cardiovascular, autonomic, cognitive, immune, and respiratory systems are all affected—but analyzing each in isolation misses the pattern.
Cross-system coordination measures will distinguish Long COVID from recovered with AUC >0.80, outperforming any single biomarker by >10%.
Multi-system coordination scores will correlate with functional impairment (r >0.50) and predict work disability status.
Unsupervised clustering will reveal ≥3 distinct phenotypes (autonomic-dominant, inflammatory-dominant, neurological-dominant) with different treatment responses.
Multi-system coordination change will correlate with symptom improvement (r >0.40), enabling objective treatment monitoring.