In chronic bacterial prostatitis there are bacteria in the prostate, but there may be no symptoms or milder symptoms than occur with acute prostatitis. The prostate infection is diagnosed by culturing urine as well as prostate fluid (expressed prostatic secretions or EPS) which are obtained by the doctor performing a rectal exam and putting pressure on the prostate. If no fluid is recovered after this prostatic massage, a post massage urine should also contain any prostatic bacteria.

Prostate specific antigen levels may be elevated, although there is no malignancy. Semen analysis is a useful diagnostic tool. Semen cultures are also performed. Antibiotic sensitivity testing is also done to select the appropriate antibiotic. Other useful markers of infection are seminal elastase and seminal cytokines.

Acute prostatitis is relatively easy to diagnose due to its symptoms that suggest infection. The organism may be found in blood or urine, and sometimes in both. Common bacteria are "Escherichia coli, Klebsiella, Proteus, Pseudomonas, Enterobacter, Enterococcus, Serratia," and "Staphylococcus aureus." This can be a medical emergency in some patients and hospitalization with intravenous antibiotics may be required. A complete blood count reveals increased white blood cells. Sepsis from prostatitis is very rare, but may occur in immunocompromised patients; high fever and malaise generally prompt blood cultures, which are often positive in sepsis. A prostate massage should never be done in a patient with suspected acute prostatitis, since it may induce sepsis. Since bacteria causing the prostatitis is easily recoverable from the urine, prostate massage is not required to make the diagnosis. Rectal palpation usually reveals an enlarged, exquisitely tender, swollen prostate gland, which is firm, warm, and, occasionally, irregular to the touch. C-reactive protein is elevated in most cases.

Prostate biopsies are not indicated as the (clinical) features (described above) are diagnostic. The histologic correlate of acute prostatitis is a neutrophilic infiltration of the prostate gland.

Acute prostatitis is associated with a transiently elevated PSA, i.e., the PSA is increased during an episode of acute prostatitis and then decreases again after it has resolved. PSA testing is not indicated in the context of uncomplicated acute prostatitis.

In the United Kingdom, NGU is more often called non-specific urethritis; "" is a medical term meaning "specific cause has not been identified", and in this case refers to the detection of urethritis, and the testing for but found negative of gonorrhea. In this sense, the most likely cause of NSU is a chlamydia infection.

However, the term NSU is sometimes distinguished and used to mean that both gonorrhea and chlamydia have been ruled out. Thus, depending on the sense, chlamydia can either be the most likely cause or have been ruled out, and frequently detected organisms are "Ureaplasma urealyticum" and "Mycoplasma hominis".

Antibiotic therapy has to overcome the blood/prostate barrier that prevents many antibiotics from reaching levels that are higher than minimum inhibitory concentration. A blood-prostate barrier restricts cell and molecular movement across the rat ventral prostate epithelium. Treatment requires prolonged courses (4–8 weeks) of antibiotics that penetrate the prostate well. The fluoroquinolones, tetracyclines and macrolides have the best penetration. There have been contradictory findings regarding the penetrability of nitrofurantoin , quinolones (ciprofloxacin, levofloxacin), sulfas (Bactrim, Septra), doxycycline and macrolides (erythromycin, clarithromycin). This is particularly true for gram-positive infections.

In a review of multiple studies, Levofloxacin (Levaquin) was found to reach prostatic fluid concentrations 5.5 times higher than Ciprofloxacin, indicating a greater ability to penetrate the prostate.

Persistent infections may be helped in 80% of patients by the use of alpha blockers (tamsulosin (Flomax), alfuzosin), or long term low dose antibiotic therapy. Recurrent infections may be caused by inefficient urination (benign prostatic hypertrophy, neurogenic bladder), prostatic stones or a structural abnormality that acts as a reservoir for infection.

In theory, the ability of some strains of bacteria to form biofilms might be one factor amongst others to facilitate development of chronic bacterial prostatitis.

Escherichia coli extract and cranberry have a potentially preventive effect on the development of chronic bacterial prostatitis, while combining antibiotics with saw palmetto, lactobacillus sporogens and arbutin may lead to better treatment outcomes.

Bacteriophages hold promise as another potential treatment for chronic bacterial prostatatis.

The addition of prostate massage to courses of antibiotics was previously proposed as being beneficial and prostate massage may mechanically break up the biofilm and enhance the drainage of the prostate gland. However, in more recent trials, this was not shown to improve outcome compared to antibiotics alone.

In female patients, urethritis can be caused by pelvic inflammatory disease.

In males, thepenis and testicles may show signs of pain and swelling. The urethra is visually examined by spreading the urinary meatus apart with two gloved fingers, and examining the opening for redness, discharge and other abnormalities. Next, a cotton swab is inserted 1-4 cm into the urethra and rotated once. To prevent contamination, no lubricant is applied to the swab, which can result in pain or discomfort. The swab is then smeared onto a glass slide and examined under a microscope. A commonly used cut-off for the diagnosis of urethritis is 5 or more granulocytes per High Power Field, but this definition has recently been called into doubt. The physician sometimes performs a digital rectal examination to inspect the prostate gland for swelling or infection.

A urinary tract infection may cause similar symptoms.

Antibiotics are the first line of treatment in acute prostatitis. Antibiotics usually resolve acute prostatitis infections in a very short time, however a minimum of two to four weeks of therapy is recommended to eradicate the offending organism completely. Appropriate antibiotics should be used, based on the microbe causing the infection. Some antibiotics have very poor penetration of the prostatic capsule, others, such as ciprofloxacin, trimethoprim/sulfamethoxazole, and tetracyclines such as doxycycline penetrate prostatic tissue well. In acute prostatitis, penetration of the prostate is not as important as for category II because the intense inflammation disrupts the prostate-blood barrier. It is more important to choose a bactericidal antibiotic (kills bacteria, e.g., a fluoroquinolone antibiotic) rather than a bacteriostatic antibiotic (slows bacterial growth, e.g. tetracycline) for acute potentially life-threatening infections.

Severely ill patients may need hospitalization, while nontoxic patients can be treated at home with bed rest, analgesics, stool softeners, and hydration. Men with acute prostatitis complicated by urinary retention are best managed with a suprapubic catheter or intermittent catheterization. Lack of clinical response to antibiotics should raise the suspicion of an abscess and prompt an imaging study such as a transrectal ultrasound (TRUS).

Risk of some causes of urethritis can be lessened by avoiding unprotected sexual activity, chemicals that could irritate the urethra; this could include detergents or lotions as well as spermicides or contraceptives, and irritation caused by manual manipulation of the urethra.

It has been easy to test for the presence of gonorrhea by viewing a Gram stain of the urethral discharge under a microscope: The causative organism is distinctive in appearance; however, this works only with men because other non-pathogenic gram-negative microbes are present as normal flora of the vagina in women. Thus, one of the major causes of urethritis can be identified (in men) by a simple common test, and the distinction between gonococcal and non-gonococcal urethritis arose for this reason.

Non-gonococcal urethritis (NGU) is diagnosed if a person with urethritis has no signs of gonorrhea bacteria on laboratory tests. The most frequent cause of NGU (23%-55% of cases) is "C. trachomatis".

To make the diagnosis of a urinary tract infection in children, a positive urinary culture is required. Contamination poses a frequent challenge depending on the method of collection used, thus a cutoff of 10 CFU/mL is used for a "clean-catch" mid stream sample, 10 CFU/mL is used for catheter-obtained specimens, and 10 CFU/mL is used for suprapubic aspirations (a sample drawn directly from the bladder with a needle). The use of "urine bags" to collect samples is discouraged by the World Health Organization due to the high rate of contamination when cultured, and catheterization is preferred in those not toilet trained. Some, such as the American Academy of Pediatrics recommends renal ultrasound and voiding cystourethrogram (watching a person's urethra and urinary bladder with real time x-rays while they urinate) in all children less than two years old who have had a urinary tract infection. However, because there is a lack of effective treatment if problems are found, others such as the National Institute for Health and Care Excellence only recommends routine imaging in those less than six months old or who have unusual findings.

In straightforward cases, a diagnosis may be made and treatment given based on symptoms alone without further laboratory confirmation. In complicated or questionable cases, it may be useful to confirm the diagnosis via urinalysis, looking for the presence of urinary nitrites, white blood cells (leukocytes), or leukocyte esterase. Another test, urine microscopy, looks for the presence of red blood cells, white blood cells, or bacteria. Urine culture is deemed positive if it shows a bacterial colony count of greater than or equal to 10 colony-forming units per mL of a typical urinary tract organism. Antibiotic sensitivity can also be tested with these cultures, making them useful in the selection of antibiotic treatment. However, women with negative cultures may still improve with antibiotic treatment. As symptoms can be vague and without reliable tests for urinary tract infections, diagnosis can be difficult in the elderly.

No treatment required. It is standard practice for men with infertility and category IV prostatitis to be given a trial of antibiotics and/or anti-inflammatories, although evidence of efficacy are weak. Since signs of asymptomatic prostatic inflammation may sometimes be associated with prostate cancer, this can be addressed by tests that assess the ratio of free-to-total PSA. The results of these tests were significantly different in prostate cancer and category IV prostatitis in one study.

Analysis of the urine may show signs of urinary tract infection. Specifically, the presence of nitrite and white blood cells on a urine test strip in patients with typical symptoms are sufficient for the diagnosis of pyelonephritis, and are an indication for empirical treatment. Blood tests such as a complete blood count may show neutrophilia. Microbiological culture of the urine, with or without blood cultures and antibiotic sensitivity testing are useful for establishing a formal diagnosis, and are considered mandatory.

Urinary catheters should be inserted using aseptic technique and sterile equipment (including sterile gloves, drape, sponges, antiseptic and sterile solution), particularly in an acute care setting. Hands should be washed before and after catheter insertion. Overall, catheter use should be minimized in all patients, particularly those at higher risk of CAUTI and mortality (e.g. the elderly or those with impaired immunity).

For sexually active women who are not pregnant, screening is recommended in those under 25 and others at risk of infection. Risk factors include a history of chlamydial or other sexually transmitted infection, new or multiple sexual partners, and inconsistent condom use. For pregnant women, guidelines vary: screening women with age or other risk factors is recommended by the U.S. Preventive Services Task Force (USPSTF) (which recommends screening women under 25) and the American Academy of Family Physicians (which recommends screening women aged 25 or younger). The American College of Obstetricians and Gynecologists recommends screening all at risk, while the Centers for Disease Control and Prevention recommend universal screening of pregnant women. The USPSTF acknowledges that in some communities there may be other risk factors for infection, such as ethnicity. Evidence-based recommendations for screening initiation, intervals and termination are currently not possible. For men, the USPSTF concludes evidence is currently insufficient to determine if regular screening of men for chlamydia is beneficial. They recommend regular screening of men who are at increased risk for HIV or syphilis infection.

In the United Kingdom the National Health Service (NHS) aims to:

1. Prevent and control chlamydia infection through early detection and treatment of asymptomatic infection;

2. Reduce onward transmission to sexual partners;

3. Prevent the consequences of untreated infection;

4. Test at least 25 percent of the sexually active under 25 population annually.

5. Retest after treatment.

If a kidney stone is suspected (e.g. on the basis of characteristic colicky pain or the presence of a disproportionate amount of blood in the urine), a kidneys, ureters, and bladder x-ray (KUB film) may assist in identifying radioopaque stones. Where available, a noncontrast helical CT scan with 5 millimeter sections is the diagnostic modality of choice in the radiographic evaluation of suspected nephrolithiasis. All stones are detectable on CT scans except very rare stones composed of certain drug residues in the urine. In patients with recurrent ascending urinary tract infections, it may be necessary to exclude an anatomical abnormality, such as vesicoureteral reflux or polycystic kidney disease. Investigations used in this setting include kidney ultrasonography or voiding cystourethrography. CT scan or kidney ultrasonography is useful in the diagnosis of xanthogranulomatous pyelonephritis; serial imaging may be useful for differentiating this condition from kidney cancer.

Ultrasound findings that indicate pyelonephritis are enlargement of the kidney, edema in the renal sinus or parenchyma, bleeding, loss of corticomedullary differentiation, abscess formation, or an areas of poor blood flow on doppler ultrasound. However, ultrasound findings are seen in only 20% to 24% of people with pyelonephritis.

A DMSA scan is a radionuclide scan that uses dimercaptosuccinic acid in assessing the kidney morphology. It is now the most reliable test for the diagnosis of acute pyelonephritis.

Diagnosis is through tests of semen, expressed prostatic secretion (EPS) or prostate tissue that reveal inflammation in the absence of symptoms.

The term "prostatitis" refers, in its strictest sense, to histological (microscopic) inflammation of the tissue of the prostate gland. Like all forms of inflammation, it can be associated with an appropriate response of the body to an infection, but it also occurs in the absence of infection.

In 1999, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) devised a new classification system. For more specifics about each type of prostatitis, including information on symptoms, treatment, and prognosis, follow the links to the relevant full articles.

In 1968, Meares and Stamey determined a classification technique based upon the culturing of bacteria. This classification is no longer used.

The conditions are distinguished by the different presentation of pain, white blood cells (WBCs) in the urine, duration of symptoms and bacteria cultured from the urine. To help express prostatic secretions that may contain WBCs and bacteria, prostate massage is sometimes used.

Research has shown a link between trichomoniasis and two serious sequelae. Data suggest that:

- Trichomoniasis is associated with increased risk of transmission and infection of HIV.

- Trichomoniasis may cause a woman to deliver a low-birth-weight or premature infant.

- The role of trichomonas infection in causing cervical cancer is unclear, although trichomonas infection may be associated with co-infection with high-risk strains of HPV.

- "T. vaginalis" infection in males has been found to cause asymptomatic urethritis and prostatitis. In the prostate, it may create chronic inflammation that may eventually lead to prostate cancer.

Regular testing for sexually transmitted infections is encouraged for prevention. The risk of contracting pelvic inflammatory disease can be reduced by the following:

- Using barrier methods such as condoms; see human sexual behavior for other listings.

- Seeking medical attention if you are experiencing symptoms of PID.

- Using hormonal combined contraceptive pills also helps in reducing the chances of PID by thickening the cervical mucosal plug & hence preventing the ascent of causative organisms from the lower genital tract.

- Seeking medical attention after learning that a current or former sex partner has, or might have had a sexually transmitted infection.

- Getting a STI history from your current partner and strongly encouraging they be tested and treated before intercourse.

- Diligence in avoiding vaginal activity, particularly intercourse, after the end of a pregnancy (delivery, miscarriage, or abortion) or certain gynecological procedures, to ensure that the cervix closes.

- Reducing the number of sexual partners.

- Sexual monogamy.

- Abstinence

Use of male condoms or female condoms may help prevent the spread of trichomoniasis, although careful studies have never been done that focus on how to prevent this infection. Infection with Trichomoniasis through water is unlikely because "Trichomonas vaginalis" dies in water after 45–60 minutes, in thermal water after 30 minutes to 3 hours and in d urine after 5–6 hours.

Currently there are no routine standard screening requirements for the general U.S. population receiving family planning or STI testing. The Centers for Disease Control and Prevention (CDC) recommends Trichomoniasis testing for females with vaginal discharge and can be considered for females at higher risk for infection or of HIV-positive serostatus.

The advent of new, highly specific and sensitive trichomoniasis tests present opportunities for new screening protocols for both men and women. Careful planning, discussion, and research are required to determine the cost-efficiency and most beneficial use of these new tests for the diagnosis and treatment of trichomoniasis in the U.S., which can lead to better prevention efforts.

A number of strategies have been found to improve follow-up for STI testing including email and text messaging as reminders of appointments.

The diagnosis of genital chlamydial infections evolved rapidly from the 1990s through 2006. Nucleic acid amplification tests (NAAT), such as polymerase chain reaction (PCR), transcription mediated amplification (TMA), and the DNA strand displacement amplification (SDA) now are the mainstays. NAAT for chlamydia may be performed on swab specimens sampled from the cervix (women) or urethra (men), on self-collected vaginal swabs, or on voided urine. NAAT has been estimated to have a sensitivity of approximately 90% and a specificity of approximately 99%, regardless of sampling from a cervical swab or by urine specimen. In women seeking an STI clinic and a urine test is negative, a subsequent cervical swab has been estimated to be positive in approximately 2% of the time.

At present, the NAATs have regulatory approval only for testing urogenital specimens, although rapidly evolving research indicates that they may give reliable results on rectal specimens.

Because of improved test accuracy, ease of specimen management, convenience in specimen management, and ease of screening sexually active men and women, the NAATs have largely replaced culture, the historic gold standard for chlamydia diagnosis, and the non-amplified probe tests. The latter test is relatively insensitive, successfully detecting only 60–80% of infections in asymptomatic women, and often giving falsely positive results. Culture remains useful in selected circumstances and is currently the only assay approved for testing non-genital specimens. Other method also exist including: ligase chain reaction (LCR), direct fluorescent antibody resting, enzyme immunoassay, and cell culture.

A number of other causes may produce similar symptoms including appendicitis, ectopic pregnancy, hemorrhagic or ruptured ovarian cysts, ovarian torsion, and endometriosis and gastroenteritis, peritonitis, and bacterial vaginosis among others.

Pelvic inflammatory disease is more likely to reoccur when there is a prior history of the infection, recent sexual contact, recent onset of menses, or an IUD (intrauterine device) in place or if the partner has a sexually transmitted infection.

Acute pelvic inflammatory disease is highly unlikely when recent intercourse has not taken place or an IUD is not being used. A sensitive serum pregnancy test is typically obtained to rule out ectopic pregnancy. Culdocentesis will differentiate hemoperitoneum (ruptured ectopic pregnancy or hemorrhagic cyst) from pelvic sepsis (salpingitis, ruptured pelvic abscess, or ruptured appendix).

Pelvic and vaginal ultrasounds are helpful in the diagnosis of PID. In the early stages of infection, the ultrasound may appear normal. As the disease progresses, nonspecific findings can include free pelvic fluid, endometrial thickening, uterine cavity distension by fluid or gas. In some instances the borders of the uterus and ovaries appear indistinct. Enlarged ovaries accompanied by increased numbers of small cysts correlates with PID.

Laparoscopy is infrequently used to diagnose pelvic inflammatory disease since it is not readily available. Moreover, it might not detect subtle inflammation of the fallopian tubes, and it fails to detect endometritis. Nevertheless, laparoscopy is conducted if the diagnosis is not certain or if the person has not responded to antibiotic therapy after 48 hours.

No single test has adequate sensitivity and specificity to diagnose pelvic inflammatory disease. A large multisite U.S. study found that cervical motion tenderness as a minimum clinical criterion increases the sensitivity of the CDC diagnostic criteria from 83 percent to 95 percent. However, even the modified 2002 CDC criteria do not identify women with subclinical disease.

Some conditions have similar symptoms to chronic prostatitis: Bladder neck hypertrophy and urethral stricture may both cause similar symptoms through urinary reflux ("inter alia"), and can be excluded through flexible cytoscopy and urodynamic tests.

There are no definitive diagnostic tests for CP/CPPS. This is a poorly understood disorder, even though it accounts for 90–95% of prostatitis diagnoses. It is found in men of any age, with the peak incidence in men aged 35–45 years. CP/CPPS may be inflammatory (Category Ⅲa) or non-inflammatory (Category Ⅲb), based on levels of pus cells in expressed prostatic secretions (EPS), but these subcategories are of limited use clinically. In the inflammatory form, urine, semen, and other fluids from the prostate contain pus cells (dead white blood cells or WBCs), whereas in the non-inflammatory form no pus cells are present. Recent studies have questioned the distinction between categories Ⅲa and Ⅲb, since both categories show evidence of inflammation if pus cells are ignored and other more subtle signs of inflammation, like cytokines, are measured.

In 2006, Chinese researchers found that men with categories Ⅲa and Ⅲb both had significantly and similarly raised levels of anti-inflammatory cytokine TGFβ1 and pro-inflammatory cytokine IFN-γ in their EPS when compared with controls; therefore measurement of these cytokines could be used to diagnose category Ⅲ prostatitis. A 2010 study found that nerve growth factor could also be used as a biomarker of the condition.

For CP/CPPS patients, analysis of urine and expressed prostatic secretions for leukocytes is debatable, especially due to the fact that the differentiation between patients with inflammatory and non-inflammatory subgroups of CP/CPPS is not useful. Serum PSA tests, routine imaging of the prostate, and tests for Chlamydia trachomatis and Ureaplasma provide no benefit for the patient.

Extraprostatic abdominal/pelvic tenderness is present in >50% of patients with chronic pelvic pain syndrome but only 7% of controls.

Healthy men have slightly more bacteria in their semen than men with CPPS. The high prevalence of WBCs and positive bacterial cultures in the asymptomatic control population raises questions about the clinical usefulness of the standard 4-glass test as a diagnostic tool in men with CP/CPPS. The use of the four-glass test by American urologists is now rare, with only 4% using it regularly.

Men with CP/CPPS are more likely than the general population to suffer from Chronic Fatigue Syndrome (CFS), and Irritable Bowel Syndrome (IBS).

Experimental tests that could be useful in the future include tests to measure semen and prostate fluid cytokine levels. Various studies have shown increases in markers for inflammation such as elevated levels of cytokines, myeloperoxidase, and chemokines.

The disease incidence varies widely depending on the geographical location. The most extensive epidemiological survey on this subject has been carried out by Dharmasena et al. who analysed the number of neonates who developed neonatal conjunctivitis in England from 2000 to 2011. In addition to the incidence of this sight threatening infection they also investigated the time trends of the disease. According to them the incidence of Neonatal conjunctivitis (Ophthalmia Neonatorum) in England was 257 (95% confidence interval: 245 to 269) per 100,000 in 2011.