This is an open label, randomized, multicenter study to evaluate the efficacy and safety of two dose levels (2.5 mL and 5.0 mL) of Indigotindisulfonate Sodium Injection, USP 0.8% when used as an aid in the determination of ureteral patency in patients with different degrees of renal impairment.

An estimated glomerular filtration rate (eGFR) at baseline will be determined using the Modification of Diet in Renal Disease (MDRD) and standardized by using individual's body surface area as described in the FDA's Renal Impairment guidance. Qualified subjects/patients will be stratified into 4 cohorts based on their eGFR at baseline: patients with normal renal function (eGFR ≥ 90 mL/min), patients with mild (eGFR 60-89 mL/min), moderate (eGFR 30-59 mL/min) and severe (eGFR 15-29 mL/min) renal impairment.

Up to ten study centers in the United States will enroll up to approximately 12 subjects per cohort (48 subjects in total) scheduled for a surgical procedure in which the patency of the ureter must be assessed by cystoscopy following the procedure, age 18 to 85 years inclusive covering the full renal function range from normal, mild, moderate, and severe renal impairment. For each subject/patient the study will consist of a screening period (Day -30 to Day -2), a baseline evaluation (Day -1 to Day 1) and a single treatment period (Day 1) with an onsite observation period of 24 hours post-dose. After signing the informed consent, review of inclusion and exclusion criteria will be performed, the collection of concomitant medications, medical history, physical examination, baseline laboratory testing, 12-lead ECG, and vital sign measurements will be completed during the screening visit.

On the day of surgery (Day 1) subjects will be evaluated for eligibility for randomization. Eligible subjects will be stratified by cohort and randomized in a 1:1 ratio to receive a dose of either Bludigo™ high dose (5.0 mL) or Bludigo™ low dose (2.5 mL). All randomized subjects will serve as his/her own control (i.e., intra-patient controlled) for efficacy by receiving a dose of normal saline prior to receiving the randomized Bludigo™ dose. The surgeon will be blinded to the Bludigo™ dose a subject receives. Time of injection of saline and Bludigo™ will be captured.

All treated subjects will have a follow-up visit 7 to 30 days (± 2 days) after the procedure. A final telephone follow-up call will occur on Day 30 (± 2 days) in subjects who have the follow-up visit before Day 28.

Safety assessments will include monitoring of AEs during and post the procedure, clinical laboratory tests, 12-Lead ECG, and vital sign measurements.

Inclusion Criteria:

• Subjects between ≥ 18 and ≤ 85 years old
• Subjects who signed a written IRB approved, informed consent form
• Subjects scheduled for a surgical procedure in which the patency of the ureter must be assessed by cystoscopy following the procedure.
• An estimated glomerular filtration rate (eGFR) at baseline will be determined using the Modification of Diet in Renal Disease formula (MDRD) and standardized by using individual's body surface area.

Subject's renal function will be defined based on the following criteria:

• Normal subjects: eGFR of ≥90 mL/min
• Mild renal impairment: eGFR 60 to 89 mL/min
• Moderate renal impairment: eGFR 30 to 59 mL/min
• Severe renal impairment: eGFR 15 to 29 mL/min

Subjects with normal renal function that are judged to be in good health based on medical history, physical examination, vital signs, and laboratory safety tests performed at the Screening Visit and/or prior to administration of study drug.

Patients with renal impairment (mild, moderate, or severe) who have a diagnosis of chronic (>6 months), stable (no acute episodes of illness within the previous 2 months due to deterioration in renal function) renal insufficiency meeting criteria at the Screening Visit

Exclusion Criteria:

• Subjects with eGFR <15 mL/min or expected need for dialysis in the near future, or having only 1 kidney
• Subjects with known severe hypersensitivity reactions to Bludigo™ or other dyes, including contrast dyes
• Known history of drug or alcohol abuse within 6 months prior to the time of screening visit
• Subjects, as assessed by the Investigator, with conditions/concomitant diseases precluding their safe participation in this study (e.g., major systemic diseases)
• Unable to meet specific protocol requirements (e.g., scheduled visits) or subject is uncooperative or has a condition that could lead to non-compliance with the study procedures
• Subject is the Investigator or any Sub-Investigator, research assistant, pharmacist, study coordinator, other staff or relative thereof directly involved in the conduct of the protocol
• Subjects with life expectancy < 6 months
• Requirement for concomitant treatment that could bias primary evaluation.
• Subjects who are pregnant or breast-feeding