Final answer:
The most specific PE finding for acute cholecystitis is Murphy's sign. Additional diagnostic tests include abdominal ultrasound, HIDA scan, liver function tests, and a complete blood count.
Step-by-step explanation:
The most specific physical examination (PE) finding for acute cholecystitis is Murphy's sign. This sign is elicited by asking the patient to breathe out and gently placing a hand below the costal margin at the right mid-clavicular line (where the gallbladder is located), then asking the patient to breathe in. A positive Murphy's sign occurs if the patient stops breathing in due to pain, indicating irritation of the gallbladder.
Additional tests to diagnose acute cholecystitis include abdominal ultrasound, which is often the initial imaging test and can detect gallstones, and HIDA scan for evaluating gallbladder function. Blood tests such as liver function tests (LFTs) and a complete blood count (CBC) can also support the diagnosis by showing abnormal liver enzymes and a high white blood cell count, respectively, indicating inflammation or infection.