How Is Long COVID (Post-COVID Syndrome) Diagnosed? Tests, Criteria & Process
Long COVID (Post-COVID Syndrome) diagnosis relies on Full blood count (FBC), Comprehensive metabolic panel (electrolytes, creatinine, LFTs), Urinalysis. Learn the full diagnostic pathway, clinical criteria, differential workup, and what to expect at your evaluation.
Updated March 27, 2026
Long COVID (Post-COVID Syndrome) is diagnosed using Full blood count (FBC), Comprehensive metabolic panel (electrolytes, creatinine, LFTs), Urinalysis and targeted clinical evaluation. Long COVID refers to persistent symptoms lasting more than 12 weeks after acute COVID-19 infection, including fatigue, brain fog, breathlessness, and chest pain. Post-exertional malaise and autonomic dysfunction are prominent features; management is multimodal and symptom-based.
Clinical Context
The diagnostic process for Long COVID (Post-COVID Syndrome) begins with Thorough history and physical examination followed by basic blood and urine tests; targeted specialist investigation as needed. Key investigations include Full blood count (FBC), Comprehensive metabolic panel (electrolytes, creatinine, LFTs), Urinalysis, Chest X-ray. The gold standard is: Directed investigation based on clinical history and physical examination findings. Clinical guidelines from NICE / BMJ Best Practice / WHO define the diagnostic criteria and recommended investigation pathway.
Clinical Pathway
Long COVID (Post-COVID Syndrome) — Full Condition GuideCondition HubLong COVID (Post-COVID Syndrome) — Differential DiagnosisDifferentialLong COVID (Post-COVID Syndrome) — Treatment PathwaysTreatmentLong COVID (Post-COVID Syndrome) — Prognosis & OutlookPrognosisFrequently Asked Questions
How Is Long COVID (Post-COVID Syndrome) Diagnosed? Tests, Criteria & Process?+
Long COVID (Post-COVID Syndrome) is diagnosed using Full blood count (FBC), Comprehensive metabolic panel (electrolytes, creatinine, LFTs), Urinalysis and targeted clinical evaluation. Long COVID refers to persistent symptoms lasting more than 12 weeks after acute COVID-19 infection, including fatigue, brain fog, breathlessness, and chest pain. Post-exertional malaise and autonomic dysfunction are prominent features; management is multimodal and symptom-based.
How do doctors test for long COVID (post-COVID syndrome)?+
The main tests used to diagnose Long COVID (Post-COVID Syndrome) include Full blood count (FBC), Comprehensive metabolic panel (electrolytes, creatinine, LFTs), Urinalysis. Your doctor will select investigations based on your symptoms, clinical findings, and risk factors.
How long does it take to diagnose Long COVID (Post-COVID Syndrome)?+
The time to diagnosis varies. Some cases are identified within hours using clinical presentation and blood tests; others require weeks, repeated investigations, or specialist referral.
Can Long COVID (Post-COVID Syndrome) be missed on initial testing?+
Yes — Long COVID (Post-COVID Syndrome) can be missed if initial tests are negative or if the presentation is atypical. If clinical suspicion remains high, repeat testing or specialist referral is appropriate.
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