TABLE 3.

Biomarkers significantly associated with long COVID Symptoms.

Long COVID symptoms	Categories of biomarkers						References
	Acute phase protein	Biochemical marker	Cytokine/Chemokine	Neurological marker	Vascular marker	Others
Neurological symptoms	Albumin, CRP, Ferritin, Fibrinogen	β-glucan, S-Sulfocysteine	CCL2, IFN-γ, IL-4, IL-6, TNF-α	GFAP, NFL, pGFAP/pNFL	ET-1, Hemoglobin, sICAM-1, sVCAM-1, sVEGFR	Ab, Hs TnT, IGFBP-4	(19, 20, 43–46, 49, 54, 59, 60, 62)
Pulmonary symptoms	C5b-9, CRP	ALT, AST, LDH	CXCL10, IFN-β, IL-1α, IL-6, TGF-β		Col1A2, Col3A1	α-SMA, miRNA21, NT-proBNP	(21, 22, 40, 46, 51)
Multiple symptoms	Albumin, CRP, Ferritin,	1-Methylnicotinamide, 2-Phenylphenol, 3,5-Dihydroxybenzoic acid, ADA, β-glucan, CPA3, Glutamine/Glutamate ratio, Indole-3-lactic acid, L-Cystein, LDH, L-Glutamine, L-Methionine, Ornithine, Pipecolic acid, Quinolinic acid, Quinolinic acid/Tryptophan ratio, Sarcosine, ST1A1, S-Sulfocysteine, Taurine, Tryptase, uPA	CCL2, CCL3, CCL4, CCL5, CCL7, CCL19, CCL20, CCL23, CXCL1, CXCL9, CXCL10, CXCL11, Flt3L, GM-CSF, IFN-γ, IL-1α, IL-2, IL-4, IL-6, IL-7, IL-10, IL-10Rβ, IL-12β, IL-17, IL-18, IL-33, IP-10, M-CSF, SCF, TGF-α, TGF-β, TNF-α, TNF-β	GDNF, NGF-β, NT-3	Ang-2, D-dimer, ESR, ET-1, Factor VIII:C, Hemoglobin, MMP-1, MMP-9, MPO, PDGF-BB, sVCAM-1, sTM, sVEGFR, VEGF, VWF:Ag, VWF:pp	Ab, ARTN, AXIN, CASP-8, CST-5, Cystatin C, LBP, MRP8/14, NGAL, OPG, OSM, SIRT2, STAMBP, TNFRSF9, Zonulin	(40–42, 47–50, 52, 53, 55–59, 61, 62)
Cardiac symptoms					NO	NT-BNP	(63)

A detailed list of abbreviations in Table 3 can be found in Supplementary Table 2.