F8 and rheumatoid arthritis: On admission he was found to have a hemoglobin of 5.7 and elevated partial thromboplastin time (PTT), promoting further workup showing FVIII levels of <1%, with a mixing study that failed to correct suggesting the presence of inhibitors against FVIII. Other characteristics of this patient's cases included controlled rheumatoid arthritis without detectable rheumatoid factor or increased erythrocyte sedimentation rate (ESR).