In a physical examination, which is one of the most basic diagnostic methods used by a doctor, the doctor will press the abdomen to check for bladder and kidney related problems. The arms and legs too will be checked for possible swellings due to water retention. The doctor will also conduct certain reflex tests to rule out neurological problems that could be causing bladder problems. In a digital rectal examination, which is a non invasive and painless procedure, the doctor inserts a gloved finger after lubrication and checks for tenderness, enlargement and nodules. This however is not a sole diagnostic method for assessing prostate enlargement and associated problems. Other tests have to be conducted and results combined to arrive at a conclusion. 

PSA test or prostate specific antigen test is undertaken to measure the prostate specific antigen in the blood of the patient. Higher levels of PSA in the blood points to prostate cancer. However, PSA tests have been under controversy for many reasons. The fact that higher levels of PSA can be caused due to benign prostatic hyperplasia (BPH) as well makes way for misdiagnosis in many cases. PSA test cannot be used as the sole diagnostic tool for prostate enlargement. This is a blood test and is non invasive with minimal pain. 

Urinalysis is nothing but the examination of urine sample to detect the presence of blood and infection. Most cases of prostate enlargement will have blood in the urine. As urinary tract infections too have similar symptoms, undertaking a Urinalysis will help identify the exact cause of prostate enlargement. It can also help detect bladder cancer. Urinalysis is non invasive and the results must be analyzed along with the results of other tests to arrive at the correct diagnosis.

Weak flow of urine is one of the many symptoms associated with prostate enlargement. Urination will be very slow and one has to strain and exert a lot of pressure to urinate. The force of urine flow can be analyzed with this test in which the patient uses a special toilet which has a device for measuring the force of urine. Reduced and slow flow of urine might be the result of BPH. This too cannot be considered as the single most test for assessing prostate enlargement as other problems like weak muscles of the bladder and urethral problems too can lead to weak urine flow.

Cystoscopy is a minimally invasive procedure which is used for analyzing lower urinary tract problems that might be causing obstruction of the bladder and urethra. In this outpatient procedure that is conducted by a urologist, a cystoscope with a light is inserted into the urethra to check for abnormalities in the structure, prostate enlargement, blockage in the bladder due to bladder stones etc. Tissue samples are also taken during this procedure to check for cancerous formations. Cystoscopy is done under general, local or spinal anaesthesia to make the patient comfortable.

Ultrasound scan is a non invasive and safe procedure that can accurately gauge the size and the shape of the prostate gland. It can also help detect tumor growths and abnormalities in the bladder and kidneys. In a transrectal ultrasonography, the probe is inserted through the rectum to assess the shape and volume of the prostate. This is a much more accurate procedure for detecting prostate enlargement. In transabdominal ultrasonography, the device is used over the abdomen to detect abnormalities and for measuring post void residual urine.

PVR is the amount of residual urine that is left in the bladder after urination. An amount of 50 ml of residual urine is normal. Any amount more than 200 ml denotes abnormalities which need to be assessed. PVR is checked with a catheter or through a transabdominal ultrasonography. A catheter is inserted into the urethra immediately after urination to check for the amount of residual urine that is present in the bladder. Presence of abnormal amounts of PVR would require further tests to diagnose an enlarged prostate.