FAST GFR: Pilot Study to Evaluate the Safety of the FAST GFR Test in Patients.

Inclusion Criteria for Groups 1-3: * Female subjects: women must have a negative urine pregnancy test at screening and before dosing on Visit 2 and be either confirmed by the Investigator to be infertile or using a reliable method of contraception Male subjects: reproductively active men must agree to either practice abstinence or utilize adequate contraception. * Ages 19 to 75 * Subject's screening must fall into one of the available categories of estimated glomerular filtration rate (eGFR) renal function: ≥ 60 mL/min for stage normal function; 30-59 mL/min for stage 3, moderate CKD; 15-29 mL/min for stage 4, severe CKD, * Patients must not be on inotropes or vasopressors, and must be absent of significant hemodynamic instabilities. * Patients must have ceased use of the following: * nonsteroidal anti-inflammatory drugs - 6 days prior, * herbal supplements - 6 days prior to testing and * cimetidine and trimethoprim - 14 days prior to testing. * Ability to comply with study conditions Inclusion Criteria for Group 4: \- Female subjects; women must have a negative urine pregnancy test at screening and before dosing on Visit 2 and be either confirmed by the Investigator to be infertile or using a reliable method of contraception. Male subjects: reproductively active men must agree to either practice abstinence or utilize adequate contraception. * Ages 19 to 75 * For cohort 4: patients diagnosed with \[either RIFLE stage I or Acute Kidney Injury Network (AKIN) stage 2 AKI\] * Patients must not be on inotropes or vasopressors, and must be absent of significant hemodynamic instabilities. * Patients must be without evidence of clinically significant liver dysfunction * Ability to comply with study conditions Exclusion Criteria for Groups 1-3: * Positive history of any clinically significant allergic or negative reactions, side effects, or anaphylaxis to sulfa, iodine, dyes, shellfish, isotopes or dextran molecules * Previous history of nephrectomy or kidney transplant * A body weight below 40kg * A body mass index \<17 or \>40 * Subjects using Coumadin (Warfarin) who have an INR \>4 at Screening or pre-dose on Visit 2 * Past history of liver disease or screening Liver Function tests which exceed 1.5 times the upper limit of normal or an albumin of \< 2mg/dl. * Clinically significant illness within 4 weeks or a clinically significant infection within 4 weeks of screening * Received blood, donated blood, have clinically significant on-going bleeding, changing haemoglobin, or experienced significant blood loss within 2 weeks of dosing * Subjects with significant abnormal findings upon physical examination, vital signs, ECG, or clinical laboratory results at Screening * Subjects with a supine blood pressure after resting for at least 5 minutes outside the 90-145 (systolic) or mmHg or 50-95 mmHg (diastolic) range * Subjects with a supine (ECG) heart rate outside 45-105 beats/min after resting for at least 5 minutes. * Subjects with a known or suspected history of drug or alcohol misuse within 6 months prior to screening, subjects who have consumed alcohol within 48 hours of dosing, or subjects who the Investigator believes to be unfit to participate in the study due to abuse of illegal or controlled substances. * Subjects who had a positive result for Hepatitis B surface antigen (HBsAg) or Hepatitis C virus antibody (HCVAb) screen. * Subjects who have been diagnosed with acquired immune deficiency syndrome (AIDS), or test positive for human immunodeficiency virus (HIV). * Subjects who participated in another clinical trial less than 1 month prior to dosing, or who are currently enrolled in another clinical trial. * Subjects who have any condition that: * Would make him/her, in the opinion of the Investigator, unsuitable for the study * Whose condition is likely to deteriorate * Who, in the opinion of the Investigator, is not likely to complete the study for any reason Exclusion Criteria for Group 4: * Positive history of any clinically significant allergic or negative reactions, side effects, or anaphylaxis to sulfa, iodine, dyes, shellfish, isotopes or dextran molecules * Previous history of nephrectomy or kidney transplant * A body weight below 40kg * A body mass index \<17 or \>40 * Current use of prescribed anticoagulants * Past history of liver disease or screening Liver Function tests which exceed 1.5 times the upper limit of normal or an albumin of \< 2mg/dl. * Received blood, donated blood, have clinically significant on-going bleeding, changing haemoglobin, or experienced significant blood loss within 2 weeks of dosing * Subjects with a supine blood pressure after resting for at least 5 minutes outside the 90-145 (systolic) or mmHg or 50-95 mmHg (diastolic) range * Subjects with a supine (ECG) heart rate outside 45-105 beats/min after resting for at least 5 minutes. * Subjects with a known or suspected history of drug or alcohol abuse within 6 months prior to admission, who have a positive drug test or alcohol test, or who have consumed alcohol within 24 of testing * Subjects who had a positive result for Hepatitis B surface antigen (HBsAg) or Hepatitis C virus antibody (HCVAb) screen. * Subjects who have been diagnosed with acquired immune deficiency syndrome (AIDS), or test positive for human immunodeficiency virus (HIV). * Subjects who participated in another clinical trial less than 1 month prior to dosing, or who are currently enrolled in another clinical trial. * Subjects who have any condition that: * Would make him/her, in the opinion of the Investigator, unsuitable for the study * Whose condition is likely to deteriorate * Who, in the opinion of the Investigator, is not likely to complete the study for any reason