What is the diagnosis of Post-Acute COVID-19 (Coronavirus Disease 2019) Syndrome, also known as Long COVID?

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Last updated: May 12, 2025View editorial policy

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From the Guidelines

Long COVID is defined as one or more symptoms and/or signs persisting or relapsing/remitting for more than 12 weeks since an acute COVID-19 diagnosis, without an alternative explanation. Diagnosing Long COVID involves a clinical assessment based on symptoms that continue or develop after the acute infection 1. There is no single diagnostic test for Long COVID; instead, healthcare providers typically diagnose it when symptoms last longer than 12 weeks and cannot be explained by another condition. Common symptoms include:

  • Fatigue
  • Shortness of breath
  • Cognitive difficulties ("brain fog")
  • Chest pain
  • Joint pain
  • Mood changes Diagnosis usually requires a detailed medical history, including confirmation of previous COVID-19 infection (though this isn't always possible if testing wasn't done), physical examination, and sometimes blood tests, chest X-rays, or other imaging to rule out alternative causes 1. Healthcare providers may also use questionnaires to assess symptom severity and impact on daily functioning. Since Long COVID can affect multiple organ systems, a multidisciplinary approach involving different specialists may be necessary. Patients experiencing persistent symptoms after COVID-19 should consult their healthcare provider rather than attempting self-diagnosis, as proper medical evaluation is essential for appropriate management and to exclude other potential causes of ongoing symptoms. According to the most recent guidelines, individuals with post-COVID-19 syndrome should be referred to an integrated multidisciplinary assessment service if available, any time from four weeks after the start of acute COVID-19 1.

From the Research

Definition and Symptoms of Long COVID

  • Long COVID, also known as post-acute sequelae of COVID-19 (PASC), is a complex condition with persistent symptoms following SARS-Cov-2 infection 2, 3.
  • The symptoms of long COVID include fatigue, dyspnoea, cognitive impairment, and decreased quality of life, with over 200 symptoms reported 3.
  • Long COVID can affect anyone infected with SARS-CoV-2, regardless of age or the severity of the initial symptoms of COVID-19 3.

Diagnosis of Long COVID

  • Diagnosing long COVID involves medical evaluation by a multidisciplinary team and assessment of persistent symptoms with scoring systems in development 2.
  • A positive COVID-19 test during acute SARS-Cov-2 infection is not required to diagnose long COVID, and currently, there is no single laboratory finding that is definitively diagnostic for confirming or ruling out the diagnosis of long COVID 4.
  • A basic laboratory assessment is recommended for all patients with possible long COVID, and consideration for additional labs and diagnostic procedures is guided by the patient's specific symptoms 4.

Diagnostic Criteria

  • Long COVID is defined as the continuation or development of new symptoms after three months from the initial SARS-CoV-2 infection, which lasts for at least two months and has no other identifiable cause 3.
  • The current global prevalence of long COVID is estimated to be 6%, with higher prevalence among female gender, certain racial and ethnic groups, and individuals who live in nonurban areas 4.

Assessment and Management

  • Holistic assessment should include a traditional history, physical examination, and additional diagnostic testing, as indicated 4.
  • Current management strategies focus on symptom-based supportive care, with critical considerations including energy conservation strategies and addressing comorbidities and modifiable risk factors 4.
  • Rehabilitation is a key element of management to achieve functional improvement, with exercise-based therapy and telerehabilitation being essential parts of management 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Long COVID or Post-Acute Sequelae of SARS-CoV-2 Infection (PASC) and the Urgent Need to Identify Diagnostic Biomarkers and Risk Factors.

Medical science monitor : international medical journal of experimental and clinical research, 2024

Research

Long COVID and rehabilitation.

Journal of the Formosan Medical Association = Taiwan yi zhi, 2024

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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