Typical clinical signs of IC include frequent urination (≥8 times per day), urgency, pain felt during bladder filling, and pain relief after urination. On physical examination, patients may present with pressure pain in the anterior vaginal wall and bladder base. The lack of specificity of the symptoms presented by patients with this disease and the varying severity of the condition make it difficult for physicians to make a diagnosis. The diagnosis is made primarily on the basis of their clinical experience and the findings in the Interstitial Cystitis Database. The strict criteria established by the NIDDK are not advocated at this time. Routine urine culture and cytology are clinically necessary to exclude the possibility of infection or malignancy. It is also necessary to rule out other diagnoses such as ureteral calculi, bladder stones, active genital herpes, ureteral diverticulum, chemical cystitis (cyclophosphamide), radiation cystitis, and vaginitis (chlamydia, mycoplasma). If IC is suspected, other tests should be used to help clarify the diagnosis, including cystoscopy under anesthesia and bladder hydrodilation, urodynamic testing, potassium sensitivity testing, urinalysis, and bladder biopsy. Zhang Peng, Department of Urology, Beijing Chaoyang Hospital, Inner Mongolia Medical University Hospital, Department of Urology, Sichinbu and A. Cystoscopy and bladder hydrodilation Performing cystoscopy under anesthesia is not only less painful for the patient, but also provides a full understanding of the bladder and ureter. Cystodilation, on the other hand, requires the injection of fluid into the bladder under 80-100 cm of vertical water pressure until the flow rate slows and eventually stops. The urethra around the cystoscope is pressurized, which prevents outflow of fluid and ensures the accuracy of bladder volume determination. the NIDDK specifies that bladder dilation be maintained for 1-2 min, but it has been reported that 2 bladder dilations should be performed or the duration of dilation should be extended to 10 min. at the time of pressure release, the cystoscope can be used to check for renal filamentous bulbous hemorrhage. It is a punctate hemorrhage at the end of the submucosal microvasculature and is seen in the majority of patients with IC during cystoscopy. Renal filamentous bulbar hemorrhage is diffuse and distributed over at least three quadrants of the bladder. Dilatation may be followed by bleeding from the mucosal folds, suggesting classic IC or ulcerative IC, although the latter is still a valid diagnostic indicator in symptomatic patients, although it has been reported in normal women who have undergone tubal ligation. In addition, bladder hydration is used in 20-30% of patients.B. Urodynamic testing is not currently recommended for patients with IC, but certain urodynamic findings can help rule out a diagnosis of IC, including bladder volumes >150 cc at initial voiding sensation, maximum bladder volumes >350 cc at pre Nocturia was not present when baseline voiding status was measured. According to the (ICDB), ~14% of patients with IC experience involuntary bladder contractions, so the diagnosis of IC cannot be clinically excluded. However, the NIDDK defines IC too strictly for research purposes, and they consider the presence of involuntary bladder contractions in patients as an exclusion criterion for IC. “C. Potassium sensitivity tests are performed with the premise that dysregulation of bladder epithelial permeability is the underlying factor that triggers the symptoms of IC. The KCl test was proposed by Parsons as a provocation test to identify patients with IC by means of epithelial permeability dysregulation. To perform the test, a dilute potassium solution (40 mEq in 100 mL of water) is instilled into the bladder and maintained for 5 min. The degree of urinary urgency and pain is recorded before and after the test and is expressed on a scale of 0-5, with 0 indicating no urgency and pain and 5 indicating severe urgency and pain. A positive test result was determined when the score changed by ≥2. There is still disagreement about the diagnostic value of the KCl test. The disadvantage of this test is that it is less specific and false positive results can occur in patients with overactive bladder, patients with radiation cystitis, and patients with bacterial cystitis. False-negative results have also been reported in patients with severe disease . In addition, the test can cause significant discomfort and distress in positive patients. Nonetheless, it has been documented that the KCl test is useful in determining which patients are more likely to be effective after receiving treatments such as sodium xylothione and heparin aimed at restoring epithelial integrity. “E Bladder biopsy Bladder biopsy has historically played a minor role in the diagnosis of IC because its histologic features are similar to those of inflammation and are nonspecific. Although bladder biopsy can identify superficial bladder epithelial lesions and exclude carcinoma in situ, it is not necessary in the diagnosis of IC. Recent findings suggest that some histopathological features may be predictive of specific IC symptoms and may actually reduce the observed variability in IC symptomatology. In fact, an analysis of the association between histopathology and IC symptoms can be performed by applying the ICDB cohort study , which included patients who did not meet the NIDDK criteria but were clinically suspected of having IC. Of the 637 patients in the ICDB study, 211 underwent bladder biopsy and two biopsies were taken from the most severe lesions in the bladder according to the following criteria: presence of Hunner’s ulcer, punctate bleeding at the end of submucosal microvessels, and absence of Hunner’s ulcer and punctate bleeding at the end of submucosal microvessels in the posterior bladder wall. In addition, a small biopsy was taken from the bladder triangle as a control within the group. Patients’ urinary urgency and pain symptoms were evaluated using a 10-point Likert scale, and the number of diurnal urinations was recorded for three days using a voiding diary. As previously described, there was no statistically significant association between cystoscopic pathology (whether or not Hunner’s ulcers and punctate bleeding from submucosal microvascular ends were present) and any IC symptoms. However, when patient characteristics were analyzed using an independent multifactorial prospective model, it was found that selective biopsy may correlate with nocturnal frequency, urinary frequency and urinary pain. Of particular interest are the complete absence of bladder epithelium, increased mast cells in the lamina propria, and the presence of punctate hemorrhages at the ends of microvessels in the lamina propria, all of which correlate with nocturnal enuresis. Similarly, increased vascular density in the lamina propria is associated with progressive nocturnal enuresis. Increased submucosal granulocyte aggregation is associated with increased urinary urgency and nocturia. Finally, urinary tract pain was associated with the degree of mucosal loss of the bladder epithelium and the degree of submucosal hemorrhage. Based on the summary of these significant findings, the authors concluded that the pathological diagnosis of IC should include three aspects: loss of bladder epithelial integrity, vascular damage, and mucosal mastocytosis. These findings provide a basis for some theories about the pathology of this type of disease and also demonstrate the multifactorial nature of the etiology that makes this disease so difficult to diagnose. The authors do not specify the sequential nature of these phenomena leading to the development of IC, and the relationship between the pathological features and the natural course of the disease and the outcome of treatment remains poorly understood, which still needs to be further informed by long-term follow-up