Final answer:
The urinary output of 240 mL in 12 hours should be reported to the healthcare provider as it suggests oliguria and may indicate a significant health issue that requires attention.
Step-by-step explanation:
A crucial aspect of caring for a patient with an indwelling Foley catheter is monitoring the urine output and characteristics for any abnormalities. Of the findings listed, the one that should be reported to the primary health care provider is B. 240 mL of urinary output is produced in 12 hours. This is concerning as it may indicate oliguria, which is defined as urinary excretion of less than 600 mL/day. Oliguria can occur in several conditions such as fever, shock, vomiting, and diarrhea, and it may also indicate acute kidney injury or other serious conditions that need further investigation.
The other findings mentioned: A. Ammonia odor, which can be normal depending on the urine concentration and dietary factors; C. 16-French catheter, which is a common size for adult females; and D. Drainage system hanging below the level of the bladder, which is the correct positioning to prevent reflux, are not immediately concerning or unexpected.