Post-Acute Infection Syndrome
Evidence-based diagnostic framework for post-infection conditions
Immune Dysregulation as Pathophysiological Basis
Post-Acute Infection Syndrome (PAIS), including ME/CFS and Long COVID, represents a spectrum of chronic conditions following acute infection. Characterized by persistent immune dysregulation, T-cell exhaustion, and autonomic dysfunction, documented by peer-reviewed research and recognized by major medical organizations worldwide.
Figure: 3D visualization of T-cell exhaustion with surface marker expression.
Authoritative Diagnostic Criteria
Myalgic Encephalomyelitis
Recognized by the Institute of Medicine (IOM, 2015) as a serious, chronic, complex, and systemic disease. Canadian Consensus Criteria (2003) and NICE Guidelines NG206 (2021) provide diagnostic frameworks.
Post-COVID-19 Condition
Recognized by the WHO (2021) as a distinct post-infection condition. CDC and NICE provide clinical case definitions and management guidelines.
Objective Biomarkers
Research demonstrates measurable immune dysregulation including T-cell exhaustion, reduced HRV, and complement activation, objective markers documented in peer-reviewed studies.
Diagnostic Tools
Interactive assessments demonstrating how clinical criteria work. Each tool shows which diagnostic criteria it addresses.
PAIS Quick Screen
Initial clinical screening for suspected PAIS based on core symptoms validated by Canadian Consensus Criteria and IOM Report. Maps to diagnostic criteria for ME/CFS and Long COVID.
Diagnostic Criteria Engine
Interactive diagnostic criteria mapping based on Canadian Consensus Criteria (2003), IOM Report (2015), NICE Guidelines NG206 (2021), and WHO Long COVID Definition (2021).
Red Flag Assessment
Systematic evaluation for conditions requiring exclusion before PAIS diagnosis. Essential for patient safety and appropriate differential diagnosis per clinical guidelines.
Evidence Base
Authoritative Diagnostic Criteria
Published Research Foundation
This clinical framework is designed for healthcare professionals and is based on peer-reviewed research and diagnostic criteria from major medical organizations. It is not a substitute for clinical judgment. Always consult current medical guidelines and consider individual patient factors in diagnosis and management.