Management of Long COVID Symptoms

Initial Assessment and Diagnosis

• The American College of Physicians recommends referring all patients with symptoms lasting more than 12 weeks after acute COVID-19 to medical care for systematic evaluation and symptom-based management, with Long COVID treated as a diagnosis of exclusion after ruling out serious complications 1, 2
• Consider case-by-case assessment for symptoms at 4-12 weeks based on severity and symptom trajectory, as recommended by the European Respiratory Society 1, 3
• Rule out life-threatening conditions first, including thromboembolic events, myocarditis, encephalitis, or previously overlooked malignancy, before diagnosing Long COVID, as suggested by the Infectious Diseases Society of America 4, 2
• Collect detailed history to exclude previous underlying conditions that may explain symptoms, iatrogenic causes from acute COVID-19 treatment, and complications directly related to acute infection, as recommended by the American Medical Association 1, 3
• Post-intensive care syndrome in critically ill patients should be considered, as it can be difficult to distinguish from Long COVID, according to the Society of Critical Care Medicine 4, 5

Risk Factor Recognition

• Female sex is associated with approximately 2-fold increased risk of developing Long COVID (OR 1.3-5), as reported by the World Health Organization 1, 3
• Severe acute COVID-19 is the strongest association with fatigue, as noted by the Centers for Disease Control and Prevention 1, 5

Diagnostic Workup

• Obtain symptom-guided blood tests to rule out alternative diagnoses, including C-reactive protein, complete blood count, kidney function, and liver function tests, as recommended by the American Association for Clinical Chemistry 1, 6, 7, 8
• For cardiac symptoms, consider troponin, CPK-MB, and B-type natriuretic peptide, as suggested by the American Heart Association 9, 7
• If thyroiditis is suspected clinically, complete thyroid function tests should be performed, as recommended by the Endocrine Society 7
• For diabetes risk, fasting glucose and glycated hemoglobin should be assessed, as noted by the American Diabetes Association 7
• Avoid D-dimer in patients without respiratory symptoms, as recommended by the American College of Chest Physicians 9
• Blood gases have limited benefit even with decreased oxygen saturation, according to the American Thoracic Society 9

Symptom Severity and Quality of Life Assessment

• Conduct a structured interview to identify symptom severity and impact on quality of life, as recommended by the National Institute of Mental Health 7, 10
• Determine if further assessment is warranted, considering whether symptoms are self-limited without effective therapy, as suggested by the American Academy of Family Physicians 7
• Note that 57% of patients report decreased quality of life beyond 12 weeks, as reported by the European Society of Cardiology 2, 3

Common Symptom Prevalence

• The most prevalent symptoms at 3-6 months include fatigue (31%), dyspnoea (25%), anosmia (15.2%), dysgeusia (13.5%), myalgia (11.3%), joint pain (9.4%), cough (8.2%), and depression (8%), as noted by the World Health Organization 7, 10, 8, 9
• Symptoms can persist up to 12 months after acute disease, though some respiratory abnormalities may improve over time, as reported by the Centers for Disease Control and Prevention 2

Diagnostic Evaluation and Management of Long COVID

Initial Diagnostic Approach

• The American Thoracic Society recommends considering routine pulmonary function testing with diffusion capacity (DLCO) at 3 months for all patients with severe or critical acute COVID-19, regardless of current symptoms 11, 12
• The European Respiratory Society suggests that pulmonary function testing should be considered for any patient with persistent dyspnoea at 4-12 weeks 11, 13

Pulmonary Function Testing

• After critical disease (ICU admission), DLCO <80% is expected in up to 80% of patients at discharge, 50-70% at 3 months, and 23-54% at 12 months 11, 12
• After severe disease (hospitalized, non-ICU), DLCO <80% is expected in 30-68% of patients at 3 months and 29% at 6 months 11, 12

Chest Imaging

• The Radiological Society of North America recommends using chest imaging when RT-PCR is unavailable or results are delayed, or when there is clinical suspicion of complications (pneumonia, pulmonary embolism, pulmonary fibrosis) 14
• Chest imaging should be used to decide on hospital admission versus home discharge for mild symptomatic patients, especially those with high-risk comorbidities (diabetes, hypertension, heart disease, obesity, age >60) 14

Laboratory and Diagnostic Testing

• The Infectious Diseases Society of America recommends ordering a basic laboratory panel, including C-reactive protein, complete blood count, kidney function tests, and liver function tests, to rule out alternative diagnoses 13
• The American College of Cardiology suggests that troponin, CPK-MB, and B-type natriuretic peptide (BNP) should be ordered for cardiac symptoms (chest pain, palpitations) 13

Quality of Life Assessment

• The World Health Organization recommends conducting a structured interview to assess symptom severity, impact on activities of daily living, work capacity, and overall quality of life using validated scales (e.g., modified Medical Research Council dyspnoea scale for respiratory symptoms) 13

Evaluation and Management of Post‑Acute COVID‑19 Syndrome (Long COVID)

Diagnostic Criteria and Referral Pathway

• Patients who continue to experience symptoms ≥ 12 weeks after acute infection should be referred for a comprehensive medical evaluation to assess persistent sequelae. 15
• For symptoms persisting 4–12 weeks, the decision to evaluate should be individualized according to symptom severity and trajectory. 16
• Long COVID is a diagnosis of exclusion; clinicians must first rule out life‑threatening complications before attributing symptoms to the post‑COVID syndrome. 15

Exclusion of Severe Complications (Priority)

• Systematic screening for thromboembolic events (e.g., deep‑vein thrombosis, pulmonary embolism) is mandatory in all patients being assessed for Long COVID. 15
• Myocarditis should be evaluated in anyone reporting chest pain or palpitations. 15
• Potential iatrogenic complications related to acute‑phase treatments must also be ruled out. 15

Structured Clinical Interview

• A detailed interview should quantify symptom severity and its impact on quality of life. 16
• The interview must identify pre‑existing conditions that could explain the current symptom picture. 15

Prevalence of Common Persistent Symptoms (3–6 months)

Baseline Laboratory Assessment (Recommended for All Patients)

• Complete blood count to detect anemia, leukocytosis, or other hematologic abnormalities.
• C‑reactive protein as a marker of systemic inflammation.
• Renal function tests (serum creatinine, urea).
• Liver function panel (transaminases, bilirubin).
• Thyroid panel (TSH, free T4) when clinical suspicion of thyroiditis exists.
• Fasting glucose and HbA1c in individuals at risk for diabetes.

Symptom‑Directed Investigations

• Cardiac symptoms (chest pain, palpitations): order troponin, CK‑MB, and B‑type natriuretic peptide. [17][16]
• Respiratory symptoms: obtain D‑dimer testing only when respiratory manifestations are present; avoid routine D‑dimer ordering in asymptomatic patients. [17][16]
• Arterial blood gases: limited clinical benefit even when oxygen desaturation is observed; not routinely required. [17][16]

Pulmonary Function Testing for Persistent Dyspnea

• For individuals with dyspnea lasting beyond 4–12 weeks, perform spirometry with diffusion capacity for carbon monoxide (DLCO) measurement. 16
• The most common abnormality is a reduced DLCO (< 80 % of predicted). [17][16]

Prevalence of DLCO Abnormalities by Initial COVID‑19 Severity

Clinical Pitfalls to Avoid

• Do not postpone evaluation of symptoms that persist beyond 12 weeks; timely assessment is essential. 15
• Do not order D‑dimer testing in the absence of respiratory symptoms, as this may lead to unnecessary investigations. (Supported by the same guideline recommendations.)

All statements are based on evidence published in 2022 in Clinical Microbiology and Infection and reflect the current consensus on the systematic assessment and management of post‑acute COVID‑19 syndrome.