The Nurse Is Caring for an Older Patient Experiencing New-Onset

The nurse is caring for an older patient experiencing new-onset atrial fibrillation. Which lab result is most concerning?

A) Hgb 13.8 g/dL
B) Hgb 11.0 g/dL
C) TSH 18 mU/mL
D) TSH 0.25 mU/mL