Mr Bradley is a 41 year old electrician who has been noticing blood in his semen so attends the GP surgery. He first noticed this four weeks ago and has had a further four episodes since. He denies any urethral discharge or urinary symptoms and has been married for 5 years. Blood pressure is 131/82. Examination including abdomen, prostate and testes examination is unremarkable. Urine dipstick is negative.
What is the most appropriate next step?