International classification prostatitis syndrome under the auspices of the National Institutes of Health (NIH).
| NIH type | Designation | Description |
| I | Acute bacterial prostatitis | Acute infection of the prostate |
| II | Chronic bacterial prostatitis(chronic prostatitis (CP)) | Recurrent infection of the prostate |
| III | CP/CPPSChronic abacterial prostatitis/ chronic pelvic pain syndrome (CPPS, “chronic pelvic pain syndrome”). | No detectable infection |
| III A | Inflammatory chronic pain syndrome of the pelvis | Leukocytes (white blood cells) in ejaculate, prostatic secretions, or urine after prostatic massage |
| III B | Noninflammatory chronic pain syndrome of the pelvis | No leukocytes in ejaculate (seminal discharge), prostatic secretions, or urine after prostatic massage |
| IV | Asymptomatic inflammatory prostatitis | No subjective symptoms, detected by prostate biopsy (tissue sampling from the prostate) or by leukocytes in prostatic secretions or ejaculate in the course of diagnosis for other reasons |