This is a medical question of type : exams and tests 
 How to diagnose Prostate Enlargement: Benign Prostatic Hyperplasia ? 
 A health care provider diagnoses benign prostatic hyperplasia based on
                
- a personal and family medical history  - a physical exam  - medical tests
                
Personal and Family Medical History
                
Taking a personal and family medical history is one of the first things a health care provider may do to help diagnose benign prostatic hyperplasia. A health care provider may ask a man
                
- what symptoms are present  - when the symptoms began and how often they occur  - whether he has a history of recurrent UTIs  - what medications he takes, both prescription and over the counter  - how much liquid he typically drinks each day  - whether he consumes caffeine and alcohol  - about his general medical history, including any significant illnesses or surgeries
                
Physical Exam
                
A physical exam may help diagnose benign prostatic hyperplasia. During a physical exam, a health care provider most often
                
- examines a patients body, which can include checking for      - discharge from the urethra    - enlarged or tender lymph nodes in the groin    - a swollen or tender scrotum    - taps on specific areas of the patients body  - performs a digital rectal exam
                
A digital rectal exam, or rectal exam, is a physical exam of the prostate. To perform the exam, the health care provider asks the man to bend over a table or lie on his side while holding his knees close to his chest. The health care provider slides a gloved, lubricated finger into the rectum and feels the part of the prostate that lies next to the rectum. The man may feel slight, brief discomfort during the rectal exam. A health care provider most often performs a rectal exam during an office visit, and men do not require anesthesia. The exam helps the health care provider see if the prostate is enlarged or tender or has any abnormalities that require more testing.
                
Many health care providers perform a rectal exam as part of a routine physical exam for men age 40 or older, whether or not they have urinary problems.
                
Medical Tests
                
A health care provider may refer men to a urologista doctor who specializes in urinary problems and the male reproductive systemthough the health care provider most often diagnoses benign prostatic hyperplasia on the basis of symptoms and a digital rectal exam. A urologist uses medical tests to help diagnose lower urinary tract problems related to benign prostatic hyperplasia and recommend treatment. Medical tests may include
                
- urinalysis  - a prostate-specific antigen (PSA) blood test  - urodynamic tests  - cystoscopy  - transrectal ultrasound  - biopsy
                
Urinalysis. Urinalysis involves testing a urine sample. The patient collects a urine sample in a special container in a health care providers office or a commercial facility. A health care provider tests the sample during an office visit or sends it to a lab for analysis. For the test, a nurse or technician places a strip of chemically treated paper, called a dipstick, into the urine. Patches on the dipstick change color to indicate signs of infection in urine.
                
PSA blood test. A health care provider may draw blood for a PSA test during an office visit or in a commercial facility and send the sample to a lab for analysis. Prostate cells create a protein called PSA. Men who have prostate cancer may have a higher amount of PSA in their blood. However, a high PSA level does not necessarily indicate prostate cancer. In fact, benign prostatic hyperplasia, prostate infections, inflammation, aging, and normal fluctuations often cause high PSA levels. Much remains unknown about how to interpret a PSA blood test, the tests ability to discriminate between cancer and prostate conditions such as benign prostatic hyperplasia, and the best course of action to take if the PSA level is high.
                
Urodynamic tests. Urodynamic tests include a variety of procedures that look at how well the bladder and urethra store and release urine. A health care provider performs urodynamic tests during an office visit or in an outpatient center or a hospital. Some urodynamic tests do not require anesthesia; others may require local anesthesia. Most urodynamic tests focus on the bladders ability to hold urine and empty steadily and completely and may include the following:
                
- uroflowmetry, which measures how rapidly the bladder releases urine  - postvoid residual measurement, which evaluates how much urine remains in the bladder after urination  - reduced urine flow or residual urine in the bladder, which often suggests urine blockage due to benign prostatic hyperplasia
                
More information is provided in the NIDDK health topic, Urodynamic Testing.
                
Cystoscopy. Cystoscopy is a procedure that uses a tubelike instrument, called a cystoscope, to look inside the urethra and bladder. A urologist inserts the cystoscope through the opening at the tip of the penis and into the lower urinary tract. A urologist performs cystoscopy during an office visit or in an outpatient center or a hospital. The urologist will give the patient local anesthesia; however, in some cases, the patient may require sedation and regional or general anesthesia. A urologist may use cystoscopy to look for blockage or stones in the urinary tract.
                
More information is provided in the NIDDK health topic, Cystoscopy and Ureteroscopy.
                
Transrectal ultrasound. Transrectal ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. The health care provider can move the transducer to different angles to make it possible to examine different organs. A specially trained technician performs the procedure in a health care providers office, an outpatient center, or a hospital, and a radiologista doctor who specializes in medical imaginginterprets the images; the patient does not require anesthesia. Urologists most often use transrectal ultrasound to examine the prostate. In a transrectal ultrasound, the technician inserts a transducer slightly larger than a pen into the mans rectum, next to the prostate. The ultrasound image shows the size of the prostate and any abnormalities, such as tumors. Transrectal ultrasound cannot reliably diagnose prostate cancer.
                
Biopsy. Biopsy is a procedure that involves taking a small piece of prostate tissue for examination with a microscope. A urologist performs the biopsy in an outpatient center or a hospital. The urologist will give the patient light sedation and local anesthetic; however, in some cases, the patient will require general anesthesia. The urologist uses imaging techniques such as ultrasound, a computerized tomography scan, or magnetic resonance imaging to guide the biopsy needle into the prostate. A pathologista doctor who specializes in examining tissues to diagnose diseasesexamines the prostate tissue in a lab. The test can show whether prostate cancer is present.
                
More information is provided in the NIDDK health topic, Medical Tests for Prostate Problems.