C3 and systemic lupus erythematosus: In our case, the C3 level was 114 mg/dL (reference range: 90-180 mg/dL), and the anti-dsDNA level was 25.1 IU/mL (reference: < 30 negative, >50 positive), indicating that the patient developed TM during a state of low disease activity in lupus (LLDAS).