Diagnosis is made by history and examination.

In immunocompromised patients, pus is present in the urine but often no organism can be cultured. In children, polymerase chain reaction sequencing of urine can detect fragments of the infectious agent.

The procedure differs somewhat for women and men. Laboratory testing of urine samples now can be performed with dipsticks that indicate immune system responses to infection, as well as with microscopic analysis of samples. Normal human urine is sterile. The presence of bacteria or pus in the urine usually indicates infection. The presence of hematuria, or blood in the urine, may indicate acute UTIs, kidney disease, kidney stones, inflammation of the prostate (in men), endometriosis (in women), or cancer of the urinary tract. In some cases, blood in the urine results from athletic training, particularly in runners.

Unfortunately mesna is ineffective as a treatment once hemorrhagic cystitis has developed. Although rare, once a case of radiation-induced hemorrhagic cystitis is diagnosed there is no empirically-proven treatments to heal this type of condition, which can severely degrade a patient's quality of life and might possibly lead to renal failure with risk of death.

Viral hemorrhagic cystitis in children generally spontaneously resolves within a few days.

The first step in the treatment of HC should be directed toward clot evacuation. Bladder outlet obstruction from clots can lead to urosepsis, bladder rupture, and renal failure. Clot evacuation can be performed by placing a wide-lumen bladder catheter at bedside. The bladder can be irrigated with water or sodium chloride solution. The use of water is preferable because water can help with clot lysis. Care must be taken to not overdistend the bladder and cause a perforation.. Hyperbaric oxygen (HBO2) therapy has been proven to be effective in treating radiation-induced hemorrhagic cystitis.

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.

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.

HFRS is difficult to diagnose on clinical grounds alone and serological evidence is often needed. A fourfold rise in IgG antibody titer in a 1-week interval, and the presence of the IgM type of antibodies against hantaviruses are good evidence for an acute hantavirus infection. HFRS should be suspected in patients with acute febrile flu-like illness, kidney failure of unknown origin and sometimes liver dysfunction.

Due to the atypical presentation and rarity of the infection, it takes a physician longer to diagnose than more common types of bladder infections. Diagnosis requires a personalized investigation with consideration to risk factors and symptoms (Bobba). Radiology of the abdominal or pubic region has proven to be an important tool in reaching a definitive diagnosis of conditions causing gas in the urinary tract. Computer tomography, or CT scans, are of most help due to their high sensitivity in detecting gas and air bubbles (Gheonea, Bondari). However, radiology is normally not the first tool used to diagnose. Most diagnoses are made by chance after imaging examination (Weerakkody). Sometimes, even when patients don’t show symptoms, their Emphysematous cystitis infection level can be very advanced already (De Baets, Baert). Gas in the bladder wall will often have the appearance of cobblestone or a “beaded necklace” with the use of conventional radiography (Weerakkody). Delayed diagnosis can lead to a severe infection, extension of the uterus, rupturing of the bladder, and death. Emphysematous cystitis has an overall mortality rate of 7%. However, surgery is only considered in severe cases where the disease progresses involving the ureters, kidneys, or adrenal glands. When required, surgery may be extensive. (De Baets, Baert).

The symptoms of IC/BPS are often misdiagnosed as a urinary tract infection. However, IC/BPS has not been shown to be caused by a bacterial infection and antibiotics are an ineffective treatment. IC/BPS is commonly misdiagnosed as chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) in men, and endometriosis and uterine fibroids (in women).

A diagnosis of IC/BPS is one of exclusion, as well as a review of clinical symptoms. The AUA Guidelines recommend starting with a careful patient history, physical examination and laboratory tests to assess and document symptoms of IC, as well as other potential disorders.

The KCl test, also known as the "potassium sensitivity test", is no longer recommended. The test uses a mild potassium solution to evaluate the integrity of the bladder wall. Though the latter is not specific for IC/BPS, it has been determined to be helpful in predicting the use of compounds, such as pentosan polysulphate, which are designed to help repair the GAG layer.

For complicated cases, the use of hydrodistention with cystoscopy may be helpful. Researchers, however, determined that this visual examination of the bladder wall after stretching the bladder was not specific for IC/BPS and that the test, itself, can contribute to the development of small glomerulations (petechial hemorrhages) often found in IC/BPS. Thus, a diagnosis of IC/BPS is one of exclusion, as well as a review of clinical symptoms.

In 2006, the ESSIC society proposed more rigorous and demanding diagnostic methods with specific classification criteria so that it cannot be confused with other, similar conditions. Specifically, they require that a patient must have pain associated with the bladder, accompanied by one other urinary symptom. Thus, a patient with just frequency or urgency would be excluded from a diagnosis. Secondly, they strongly encourage the exclusion of confusable diseases through an extensive and expensive series of tests including (A) a medical history and physical exam, (B) a dipstick urinalysis, various urine cultures, and a serum PSA in men over 40, (C) flowmetry and post-void residual urine volume by ultrasound scanning and (D) cystoscopy. A diagnosis of IC/BPS would be confirmed with a hydrodistention during cystoscopy with biopsy.

They also propose a ranking system based upon the physical findings in the bladder. Patients would receive a numeric and letter based score based upon the severity of their disease as found during the hydrodistention. A score of 1–3 would relate to the severity of the disease and a rating of A–C represents biopsy findings. Thus, a patient with 1A would have very mild symptoms and disease while a patient with 3C would have the worst possible symptoms. Widely recognized scoring systems such as the O'Leary Sant symptom and problem score have emerged to evaluate the severity of IC symptoms such as pain and urinary symptoms.

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.

Biochemical blood tests determine the amount of typical markers of renal function in the blood serum, for instance serum urea and serum creatinine. Biochemistry can also be used to determine serum electrolytes. Special biochemical tests (arterial blood gas) can determine the amount of dissolved gases in the blood, indicating if pH imbalances are acute or chronic.

Urinalysis is a test that studies urine for abnormal substances such as protein or signs of infection.

- A Full Ward Test, also known as dipstick urinalysis, involves the dipping of a biochemically active test strip into the urine specimen to determine levels of tell-tale chemicals in the urine.

- Urinalysis can also involve MC&S microscopy, culture and sensitivity

Urodynamic tests evaluate the storage of urine in the bladder and the flow of urine from the bladder through the urethra. It may be performed in cases of incontinence or neurological problems affecting the urinary tract.

Ultrasound is commonly performed to investigate problems of the kidney and/or urinary tract.

Radiology:

- KUB is plain radiography of the urinary system, e.g. to identify kidney stones.

- An intravenous pyelogram studies the shape of the urinary system.

- CAT scans and MRI can also be useful in localising urinary tract pathology.

- A voiding cystogram is a functional study where contrast "dye" is injected through a catheter into the bladder. Under x-ray the radiologist asks the patient to void (usually young children) and will watch the contrast exiting the body on the x-ray monitor. This examines the child's bladder and lower urinary tract. Typically looking for vesicoureteral reflux, involving urine backflow up into the kidneys.

Rodent control in and around the home remains the primary prevention strategy, as well as eliminating contact with rodents in the workplace and campsite. Closed storage sheds and cabins are often ideal sites for rodent infestations. Airing out of such spaces prior to use is recommended. Avoid direct contact with rodent droppings and wear a mask to avoid inhalation of aerosolized rodent secretions.

A urinary tract infection may involve only the lower urinary tract, in which case it is known as a bladder infection. Alternatively, it may involve the upper urinary tract, in which case it is known as pyelonephritis. If the urine contains significant bacteria but there are no symptoms, the condition is known as asymptomatic bacteriuria. If a urinary tract infection involves the upper tract, and the person has diabetes mellitus, is pregnant, is male, or immunocompromised, it is considered complicated. Otherwise if a woman is healthy and premenopausal it is considered uncomplicated. In children when a urinary tract infection is associated with a fever, it is deemed to be an upper urinary tract infection.

Diagnosis is made by patient history of passing air or a sputtering urine stream. CT scans may show air in the urinary bladder or bladder walls.

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).

Predicts mortality risk in pancreatitis with fewer variables than Ranson's criteria. Data should be taken from the first 24 hours of the patient's evaluation.

- BUN >25 mg/dL (8.9 mmol/L)

- Abnormal mental status with a Glasgow coma score <15

- Evidence of SIRS (systemic inflammatory response syndrome)

- Patient age >60 years old

- Imaging study reveals pleural effusion

Patients with a score of zero had a mortality of less than one percent, whereas patients with a score of five had a mortality rate of 22 percent. In the validation cohort, the BISAP score had similar test performance characteristics for predicting mortality as the APACHE II score. As is a problem with many of the other scoring systems, the BISAP has not been validated for predicting outcomes such as length of hospital stay, need for ICU care, or need for intervention.

Even when caught early, aggressive treatment is required (Bobba). Antibiotics are proven to cure Emphysematous cystitis over time and reduce the amount of gas inside the bladder wall. Prognosis is poor if antibiotics are not used to treat the patient. Additional treatment consists of urinary drainage and good control of blood glucose. The treatment of underlying comorbid diseases, such as diabetes, is extremely important because they can intensify the infection (Gheonea, Bondari). Hyperbaric oxygen is an effective treatment, and has cured some cases in as little as 48 hours. Although it is unclear as to how gas formation occurs in emphysematous cystitis, it’s dependant on whether or not the patient has contributing diseases (Mccabe). Gas formation in diabetic patients diagnosed with Emphysematous cystitis has been determined to occur due to the production of carbon dioxide as a result of the fermentation of the high concentrations of glucose. Gas formation in nondiabetic patients is most likely due the breaking down of urinary lactulose and tissue proteins. Inflammation caused by infection increases pressure and decreases circulation, which provides the perfect environment for bacteria to produce gas (Sereno).

In predicting the prognosis, there are several scoring indices that have been used as predictors of survival. Two such scoring systems are the Ranson criteria and APACHE II (Acute Physiology and Chronic Health Evaluation) indices. Most, but not all studies report that the Apache score may be more accurate. In the negative study of the APACHE-II, the APACHE-II 24-hour score was used rather than the 48-hour score. In addition, all patients in the study received an ultrasound twice which may have influenced allocation of co-interventions. Regardless, only the APACHE-II can be fully calculated upon admission. As the APACHE-II is more cumbersome to calculate, presumably patients whose only laboratory abnormality is an elevated lipase or amylase do not need assessment with the APACHE-II; however, this approach is not studied. The APACHE-II score can be calculated at www.sfar.org.

Practice guidelines state:

In addition to traditional IC therapies, diet modification remains a core self care strategy as foods that are irritating to the bladder dramatically worsen the symptoms that patients may experience. Foods high in acid and/or caffeine (such as all coffees, regular teas, green teas, sodas, diet sodas, artificial sweeteners and most fruit juices) should be avoided. The daily goal of patients should be to soothe rather than irritate the bladder wall.

Antigen detection, polymerase chain reaction assay, virus isolation, and serology can be used to identify adenovirus infections. Adenovirus typing is usually accomplished by hemagglutination-inhibition and/or neutralization with type-specific antisera. Since adenovirus can be excreted for prolonged periods, the presence of virus does not necessarily mean it is associated with disease.

Treatment involves avoiding the trigger if that can be determined.

Definitive diagnosis is usually made at a reference laboratory with advanced biocontainment capabilities. The findings of laboratory investigation vary somewhat between the viruses but in general there is a decrease in the total white cell count (particularly the lymphocytes), a decrease in the platelet count, an increase in the blood serum liver enzymes, and reduced blood clotting ability measured as an increase in both the prothrombin (PT) and activated partial thromboplastin times (PTT). The hematocrit may be elevated. The serum urea and creatine may be raised but this is dependent on the hydration status of the patient. The bleeding time tends to be prolonged.

There is no cure or vaccine for HPS. Treatment involves supportive therapy, including mechanical ventilation with supplemental oxygen during the critical respiratory-failure stage of the illness. Early recognition of HPS and admission to an intensive care setting offers the best prognosis.

Rodent control in and around the home or dwellings remains the primary prevention strategy, as well as eliminating contact with rodents in the workplace and campsite. Closed storage sheds and cabins are often ideal sites for rodent infestations. Airing out of such spaces prior to use is recommended. People are advised to avoid direct contact with rodent droppings and wear a mask while cleaning such areas to avoid inhalation of aerosolized rodent secretions.

Safe and effective adenovirus vaccines were developed for adenovirus serotypes 4 and 7, but were available only for preventing ARD among US military recruits, and production stopped in 1996. Strict attention to good infection-control practices is effective for stopping transmission in hospitals of adenovirus-associated disease, such as epidemic keratoconjunctivitis. Maintaining adequate levels of chlorination is necessary for preventing swimming pool-associated outbreaks of adenovirus conjunctivitis.

Glomerulation refers to bladder hemorrhages which are thought to be associated with some types of interstitial cystitis (IC).

The presence of glomerulations, also known as petechial hemorrhages, in the bladder suggests that the bladder wall has been damaged, irritated and/or inflamed. In fact, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Diagnostic Criteria for IC, developed in 1987, required the presence of glomerulations or Hunner's Ulcers to make a firm diagnosis of IC and is still used, today, to determine patient eligibility for some clinical trials. Research conducted by Waxman, however, determined that the hydrodistention procedure itself may have created these tiny broken blood vessels. Thus, a diagnosis of IC is now based upon other, less invasive methods, such as the PUF questionnaire.