Urine microscopy shows red cells but no white cells. What is the SINGLE most diagnostic test?

A 61 year old man, known smoker, comes to the hospital with complaints of painless frank haematuria. He has been worried about his loss of weight and reduced general activity. Urine microscopy shows red cells but no white cells. What is the SINGLE most diagnostic test?

A. Urine culture
B. Intravenous urogram
C. Transrectal ultrasound and biopsy
D. Cystoscopy with biopsy
E. Ultrasound of the Kidneys, Ureters & Bladder

The two most important risk factors for transitional cell carcinoma of the bladder are:

Exposure to aromatic hydrocarbons, e.g. workers in the petrochemical, industrial dye, rubber industries, chimney sweeps. Smoking

Here they give a history of smoking with loss of weight. The absence of white cells implies a non-infectious cause of the painless frank haematuria. In the elderly, one must always have transitional cell carcinoma of the bladder as part of a differential diagnosis when a patient presents with painless haematuria.

Cystoscopy is the most diagnostic test