Final answer:
The need to withhold gentamicin in a patient with osteomyelitis is indicated by changes in kidney function, not elevated liver enzymes. It is crucial to monitor renal function due to gentamicin's potential nephrotoxic effects.
Step-by-step explanation:
When reviewing the medical record of a client with osteomyelitis who is prescribed gentamicin, the finding that should indicate the need to withhold the medication is elevated liver enzymes. Gentamicin is an aminoglycoside antibiotic that can be nephrotoxic (damaging to the kidneys) and ototoxic (damaging to the ears), thus, it's crucial to monitor kidney function during treatment. Elevated liver enzymes typically suggest a problem with the liver, but it is the renal function that needs to be closely watched when using gentamicin due to its potential to cause kidney damage.