**Core Concept:** Hematuria and painless hematuria are clinical symptoms that indicate blood in the urine. Various conditions can lead to hematuria, including kidney stones, urinary tract infections, and certain medications. Painless hematuria can be caused by conditions like interstitial cystitis and urethritis. Hematuria can also be a symptom of systemic diseases like diabetes or vasculitis. In this case, we are considering the possibility of hematuria due to a renal origin.

**Why the Correct Answer is Right:** Given the context of a young office executive presenting with painless hematuria and abdominal pain, the correct answer is to perform an ultrasound scan. This is because an abdominal ultrasound can provide an image of the kidney, ureters, and bladder to help identify the cause of the painless hematuria. This is especially important in this case as abdominal pain is present, which can indicate renal, ureteric, or bladder involvement.

**Why Each Wrong Option is Incorrect:**

A. A rectal examination is not relevant in this case as it focuses on the rectum, colon, and anus, not the renal system.
B. An external examination is also irrelevant as it assesses the skin, muscles, and bones, not the renal system.
C. In this scenario, a renal function test (RFT) is not suitable as it assesses kidney function rather than identifying the source of painless hematuria.
D. A blood test is not the most appropriate next step in this case as it does not directly address the symptoms of painless hematuria and abdominal pain. Blood tests are generally performed to evaluate the cause of the symptoms, not to identify the source of the symptoms.

**Clinical Pearl:** In cases of painless hematuria, consider the possibility of a renal cause, especially when abdominal pain is present. Conducting an ultrasound scan helps identify the source of the symptoms and guides further management.