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All mechanisms

Mistaken attribution (it's something else)

Symptoms actually caused by a separate, often treatable condition — and attributed to COVID by timing.

Fatigue, brain fog, breathlessness, and palpitations have many common causes. A meaningful share of presumed Long COVID is explained by a separate, treatable condition — thyroid disease, iron deficiency, B12 deficiency, sleep apnea, diabetes, depression, or a medication effect — that happened to surface around the same time. A cheap first-tier workup (TSH, ferritin, B12/folate, vitamin D, HbA1c, CBC, metabolic panel, ESR/CRP) plus a sleep-apnea screen catches most of these. This is the highest-yield, lowest-cost step in the whole assessment: rule out the mimics before attributing everything to COVID.

How it's tested

First-tier blood panel (alternative-diagnosis screen)

$100–$300Your GP can order

TSH, ferritin, B12/folate, vitamin D, HbA1c, CBC, metabolic panel, ESR/CRP. Catches the common, treatable conditions that masquerade as Long COVID.

Sleep-apnea screen (STOP-BANG → home sleep test)

Up to $300At home

A free questionnaire that, if positive, leads to an inexpensive home sleep apnea test. Sleep apnea is common, undiagnosed, treatable, and both mimics and worsens Long COVID.

Treatment options & their evidence

Graded honestly — including treatments that failed in good trials, which is worth knowing.

Treat the underlying condition

Strong evidence

When a separate condition (thyroid, iron deficiency, sleep apnea, B12, diabetes, depression) is found, treating it directly is well-established and can resolve the symptoms entirely.