Quarks Science Cops: Why Long COVID still has no reliable diagnostic test
Why your blood tests can look normal while symptoms remain disabling — and the diagnostics-shop traps to avoid
Episode aired Sep 20, 2025·Page synthesised Jun 8, 2026·Last reviewed Jun 8, 2026
What this episode covers
- No single blood test or imaging scan can confirm Long COVID or ME/CFS (Myalgic Encephalomyelitis / Chronic Fatigue Syndrome) as of late 2025.
- Some private providers sell expensive lab panels that promise a diagnosis the panels cannot actually deliver.
- The illness has multiple plausible biological causes under serious research, and dismissing symptoms as 'imagined' delays proper care.
Why it matters
If no single test confirms Long COVID, then patients face long waiting periods, multiple specialist visits, and the risk of wasted spending on unproven private panels. The diagnostic gap also delays decisions about work capacity, disability support, and treatment choices across cardiology, neurology, immunology, and psychiatry care.
What stands out
- Standard blood tests and imaging cannot diagnose Long COVID or ME/CFS as of late 2025, despite many private clinics selling 'diagnostic panels' that suggest otherwise (Robert Koch Institute (RKI) guidance + 2024 US cohort study)
- Long COVID is most likely several distinct illness subtypes, not a single disease — which is why treatment that helps one patient may not help another (Iwasaki endotype framing + multiple mechanism studies)
- 'Psychosomatic' in modern medicine does not mean 'imagined' or 'made up'; it means psyche and body interact across most chronic illness (Henningsen biopsychosocial framework)
Best-supported action
The single highest-leverage move from this episode, anchored in the strongest evidence the speaker presents.
If a provider claims a multi-tier blood-test panel confirms Long COVID, ask for peer-reviewed evidence linking it to clinical outcomes — absence is itself a useful signal.
Where to start
Small low-friction starters covering the main moves from this episode.
- Document your symptoms over weeks with severity scores and timing so you have a credible clinical baseline regardless of which lab tests are run
- Look for university-affiliated Long COVID clinics rather than private providers offering expensive 'comprehensive' panels without published outcome data
- If a provider claims a multi-tier blood-test panel can diagnose Long COVID, ask for peer-reviewed evidence linking the panel to clinical outcomes — absence is itself a useful signal
Other supported actions
Further actions discussed in this episode, ordered from strongest to weakest evidence. This is one expert's view, the full topic compares and ranks across experts.
- Consider asking for a thorough differential-diagnosis workup at a specialist post-COVID clinic before pursuing private diagnostic panels, to rule out other treatable conditions first.Strong evidence
- Consider keeping a daily symptom-and-exertion diary for 4 to 6 weeks (sleep, energy, brain fog on 1-10 scales, daily activity, foods) to help your clinician identify patterns and exertion triggers.Moderate evidence
- Consider a second-opinion consultation if your current doctor is unfamiliar with Long COVID and ME/CFS clinical patterns; specialist familiarity may shape both diagnostic and treatment options.Moderate evidence
Full context, impact ratings, and timing — available in related topics
Questions to take to your doctor
- Given my persistent symptoms after a COVID infection and normal standard test results, what differential diagnoses should we rule out before assuming this is Long COVID?
- Given the lack of a confirmed biomarker, how should we evaluate whether a treatment is working for me — what specific symptoms or measures should we track?
- Given the private clinic offerings I've seen, do any of these labs add diagnostic value over what we've already done?
Full doctor prep with ranked questions available in the full topic page
Context
The expert emphasizes translating research into actionable steps, focusing on what the evidence actually supports versus common assumptions.
This does not prove that all Long COVID patients have the same mechanism or will respond to the same treatment.
This does not prove that all psychological factors are irrelevant; nocebo and avoidance behaviors can shape outcomes in some cases.
This does not prove that private diagnostic clinics are universally fraudulent; some may have legitimate specialist care alongside the unproven panels.
This does not mean you should change or stop any current medical treatment on your own.
Where people go wrong
- Paying for expensive private 'Long COVID' diagnostic panels expecting confirmation of the diagnosis.May spend several hundred to several thousand euros for results that do not change your treatment and that no peer-reviewed evidence links to clinical outcomes. The diagnostic gap is not yet solved by commercial labs.
- Accepting 'it's all in your head' as a complete clinical explanation when symptoms remain disabling despite normal standard test results.May delay proper differential diagnosis, miss treatable conditions (sleep apnea, thyroid issues, anemia, autonomic dysfunction), and prevent access to current symptom-management options. Normal standard tests do not equal absence of organic illness.
What to expect over time
- Weeks 1 to 4Get a thorough differential-diagnosis workup from a primary care doctor or specialist. Standard tests likely look normal even when symptoms are real.
- Months 1 to 6Find a doctor familiar with Long COVID and ME/CFS. Start a symptom diary. Avoid expensive private 'diagnostic panels' that overpromise.
- 6 to 18 monthsMost patients improve meaningfully within a year per clinical observation. Some develop a more chronic course requiring specialist care and ongoing pacing.