Table 1.
Testable predictions derived from a mechanism-based stratification framework in long COVID primary mechanistic domains represent physiologic regulatory systems capable of independently generating multisystem symptoms, whereas secondary amplifiers represent processes that intensify or sustain dysregulation across domains.
| Primary mechanistic domain | Example objective measures | Hypothesis-generating translational prediction |
|---|---|---|
| Dysautonomia | Tilt-table testing, active stand test, heart rate variability metrics, plasma catecholamines (11, 12) | Patients with objective orthostatic abnormalities may demonstrate greater responsiveness to autonomic-modulating therapies than symptom-defined cohorts alone |
| Mitochondrial/bioenergetic dysfunction | Cardiopulmonary exercise testing, exertional lactate dynamics, metabolomic profiling (8, 13) | Patients with exertion-triggered metabolic instability may demonstrate clearer functional improvement with metabolic-targeted or mitochondrial-supportive interventions |
| Endothelial/microvascular dysfunction | Flow-mediated dilation, endothelial biomarkers, microvascular perfusion imaging (8, 46) | Vascular-directed therapies may demonstrate stronger therapeutic signal in patients with measurable endothelial dysfunction |
| Gut Dysbiosis/barrier dysfunction | Microbiome profiling, permeability-associated markers, LPS-related biomarkers (14, 41–43) | Gut-targeted interventions may preferentially improve inflammatory and systemic symptoms in biologically enriched subsets |
| Mast cell activation | Serum tryptase, histamine metabolites, and other mast cell mediator panels, when elevated or obtained during symptomatic periods (15–17) | Histamine blockade or mast cell-modulating therapies may yield differential responses in patients with mediator elevation or classic mast cell symptom patterns |
| Neuroendocrine dysregulation | Thyroid panel, cortisol rhythm assessment, sex hormone levels (19–23) | Hormonal correction in patients with objective endocrine abnormalities may produce broader multisystem improvement than in unselected cohorts |
| Secondary amplifiers: immune activation, neuroinflammation, autoantibodies, viral antigen persistence | Cytokine profiling, CSF inflammatory markers, neuroimaging evidence of microglial activation, autoantibody panels, tissue antigen detection in selected cases (24–30) | Combination or multi-domain therapies may demonstrate greater clinical improvement in patients with objective immune activation, neuroinflammation, or viral persistence markers |
This table illustrates how domain-based stratification generates falsifiable predictions. The framework is inherently falsifiable: if biologically enriched cohorts do not demonstrate differential treatment responsiveness compared with symptom-defined groups, the model would require refinement. HRV, heart rate variability; LPS, lipopolysaccharide.