Diagnosis of enlarged prostate is based upon medical history in conjunction with medical testing. Symptoms alone are not a reliable diagnosis because there are other conditions that mimic the symptoms of enlarged prostate (urerthral stricture, bladder cancer, prostatitis, neurogenic bladder, diabetes mellitus).

A symptom score is widely used to determine whether a physical examination is required. The American Urological Association Symptom index is the most commonly used symptom index. Symptoms are classified according to the total score as mild (1-7), moderate (8-19) or severe (20-35). Generally, no treatment is needed if symptoms are mild. Moderate symptoms usually require some form of treatment and severe symptoms most often lead to surgical treatment.

A physical exam will involve the examination of the abdomen for a full bladder and the prostate gland for an assessment of it’s size, shape and consistency. This is achieved by way of a digital rectum examination, in which the doctor inserts a gloved finger into the rectum. The prostate, which is situated immediately adjacent to the anterior wall, is easily accessible in this manner. The doctor will be checking to see if the enlargement of the prostate is smooth and rubbery (consistent with BPH) or hard and nodular (consistent with prostate cancer).

Further tests that will be conducted to confirm BPH are a urine analysis and a urine flow rate test. Simple urine analysis can be performed in the office with dipstix. If this indicates possible infection a urine culture should be obtained. If the urine contains blood this should be further investigated to rule out other causes.

A urine flow rate is performed by asking the patient to pass urine into a machine, which measures urine flow rate. Most machines measure the volume of urine, the maximum flow rate and the time taken to empty the bladder. For a flow rate test to be of value the patient needs to pass at least 125-150 ml of urine at one time.

The most useful parameter is the maximum flow rate or Q-max, measured in millilitres per second. Although flow is only an indirect measure of obstruction, most patients with a flow rate less than 10 ml/second will prove to have bladder outflow obstruction, whereas most patients with a flow rate of more than 15 ml/second will not have evidence of obstruction.

An assessment of renal function will also be taken as part of the diagnosis process. This will be achieved via a blood sample which measures the level of serum creatinine.