aPCR	asymmetric polymerase chain reaction
AxSpA	axial spondyloarthritis
BSA	bovine serum albumin
CPG	controled pore glass
DKK-1	Dickkopf-1 protein
EDC	N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride
ELASA	enzyme-linked aptamer sorbent assay
ELONA	enzyme-linked oligonucleotide assay
EMSA	electrophoretic mobility shift assay
HRP	horseradish peroxidase
HSA	human serum albumin
NHS	N-hydroxysuccinimide
PBS	Phosphate-Buffered Saline
PEG	poly(ethylene glycol)
SELEX	Systematic Evolution of Ligands by Exponential Enrichment
TMB	3,3′,5,5′-tetramethylbenzidine
4PL	four-parameter logistic regression