The nurse assesses an older adult client who reports feeling weak and dizzy. Which finding is the most reliable indicator of dehydration in this client?

The correct answer to the question "The nurse assesses an older adult client who reports feeling weak and dizzy. Which finding is the most reliable indicator of dehydration in this client?" is Option D: Increased heart rate with orthostatic hypotension..

The other options — A) Dry oral mucous membranes., B) Decreased skin turgor over the forearm., C) Dark, concentrated urine. — are incorrect for this NCLEX-RN Exam Prep question. As explained above: In older adults, skin turgor is less reliable due to decreased elasticity. Orthostatic hypotension with an increased heart rate is a more reliable and critical indicator of fluid volume deficit.