Assessment of Carboplatin Clearance Predictors: A PK Study on NCI-Sponsored Clinical Trials or Standard of Care Treatments Using Carboplatin.

Inclusion Criteria: - Patients must have the psychological ability and general health that permits completion of the study requirements and required follow up - For men who are sexually active, the need for use of medically acceptable contraception will be dictated by the primary treatment plan/protocol - Study accrual was closed to women on 08/18/2021 and accrual is now only open to males in order to meet accrual goals and study objectives. (11-AUG-2021) - Male sex - Any patients who will receive treatment with intravenous carboplatin (any AUC, any cycle) on a National Cancer Institute (NCI)-sponsored National Clinical Trial Network (NCTN)-, Experimental Therapeutics Clinical Trials Network (ETCTN)-, trial, local trial, or through standard of care - Age >= 18 - The patient or a legally authorized representative must provide study-specific informed consent prior to study entry Exclusion Criteria: - Treated at an institute where creatinine is not measured with an IDMS calibrated assay - History of allergic reactions to computed tomography (CT) contrast, iodine or shellfish, or history of anaphylactic reaction to any food item - Recent (last 6 months) episode of acute kidney injury, have sickle cell disease, or have current indwelling nephrostomy tubes - Edema beyond trace edema, because this will impact iohexol equilibration and distribution - Ascites (including pleural effusion) beyond trace ascites, because this will impact iohexol equilibration and distribution - Whole- or part-limb amputees, because this will impact iohexol equilibration and distribution - Inability to maintain a constant dose and schedule of anti-inflammatory agents, diuretics, angiotensin II receptor blockers (ARB) and angiotensin converting enzyme inhibitors (ACEi) for one week prior to study visit, as this impacts renal function. If the patient is on a nonsteroidal anti-inflammatory drug (NSAID), diuretic, ARB or ACEi, they are eligible as long as these agents are taken on a set schedule for 7 or more days prior to study (and not on an "as needed" basis as that can cause fluctuations in renal function) - Inadequate venous access to obtain pharmacokinetic (PK) specimens - Multinodular goiter, Graves' disease or autoimmune thyroiditis, per iohexol package insert (hypothyroidism is allowed)