TNF and rheumatoid arthritis: <h4>Background</h4>Therapeutic drug monitoring (TDM) of anti-TNF biologics may help optimise treatment in rheumatoid arthritis (RA), but current therapeutic ranges do not always reflect clinical response in routine practice.<h4>Methods</h4>We conducted a retrospective observational study including 224 adults with RA treated with infliximab (IFX), adalimumab (ADL), or etanercept (ETN) during the maintenance phase at Hospital Universitario Puerto Real between May 2016 and May 2023.