Which tests should be performed in the diagnosis of prostatitis?

Updated: Jan 02, 2020
  • Author: John L Brusch, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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In acute bacterial prostatitis, most patients have pyuria and bacteruria, allowing the infecting organism to be isolated by midstream urine collection. Blood cultures, a complete blood count (CBC), and a basic metabolic panel should be obtained.

In chronic bacterial prostatitis, bacteria and leukocytes may or may not be observed in prostate-specific secretions (ie, expressed prostatic secretions [EPS] or a third midstream bladder specimen [VB3] postprostatic massage). More than 15 leukocytes/HPF is abnormal.

4-Glass test

Although the 4-glass test is the standard for the diagnosis of chronic prostatitis, it is used infrequently.

The 4-glass test was described by Meares and Stamey in 1968 to accurately localize bacteria (ie, urethra vs prostate). [5] One should obtain simultaneous cultures of: (1) urethral urine,(ie, first voided bladder specimen [VB1]); (2) midstream urine (ie, second midstream bladder specimen [VB2]); (3) EPS; and (4) VB3.

The tests should be performed when the patient does not have significant bacteruria, and the specimens must be quantitatively cultured immediately after collection.

If bacteruria is present, ampicillin, cephalexin, or nitrofurantoin should be given for 2-3 days to sterilize the urine; these agents are not effective against chronic bacterial prostatitis. If the number of bacteria in EPS ejaculate or VB3 exceeds that in VB1 or VB2 by at least 10-fold, the infection is prostatic in origin.

Premassage/postmassage test

A simpler procedure for the diagnosis of chronic prostatitis was suggested by Nickel. [10] In the premassage and postmassage test, urine is obtained before and after prostate massage. These specimens are sent for culture and sediment microscopy. If bacteria and leukocytosis in the postmassage specimen exceed those in the premassage specimen, category II prostatitis is suggested. Leukocytosis alone indicates category IIIA, whereas no bacteria or leukocytosis indicates category IIIB.

Postvoid residual urine volume measurement

Measurement of the postvoid residual urine volume may be helpful in the older patient for whom prostatism is suspected. Although this measurement is traditionally performed via catheterization, some institutions are now using ultrasonography for this measurement. [11] If the postvoid residual urine volume is elevated, then a urinary catheter must be placed and urologic consultation obtained.

Urodynamic studies

Chronic prostatitis may result in an element of bladder neck obstruction, which may be demonstrated by urodynamic studies and may be corrected with transurethral surgery. [3]

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