Clinical Research Directory

Inclusion Criteria: 1. Age \>/=18 years at the time of enrollment. 2. Residing in an ICU. 3. Documented or suspected Antimicrobial Resistant (AMR) Gram-negative infection for which the prospective participant is receiving meropenem or cefepime as part of their clinical management. 4. Expectation that the prospective participant will reside in the ICU and receive meropenem or cefepime for the duration of the study, and that all study procedures will be completed. 5. Expectation that IV access will be sufficient for drug infusion and either IV or arterial access will be sufficient to allow for all protocol-required blood sampling to occur. 6. The prospective participant, or their legally authorized representative (LAR), is able and willing to provide signed informed consent Exclusion Criteria: 1. Prospective participant has a documented hypersensitivity or allergic reaction to iohexol, any contrast agents, or iodine. 2. Prospective participant has a documented prior history of severe cutaneous reactions to iohexol, any contrast agents, or iodine. 3. Prospective participant received iohexol within one calendar day prior to enrollment or the expectation that they will receive iohexol for clinical care (i.e., Standard of Care \[SOC\]) during the study. 4. Prospective participant had a major surgery\* within two calendar days prior to enrollment. \*Major surgery will be defined as "the opening of either a body cavity or the mesenchymal barrier, using general anesthesia." 5. Prospective participant had a recent (within 6 months) burn involving \> 25% of total body surface area. 6. Prospective participant had a penetrating injury\* within two calendar days prior to enrollment. \*Penetrating injury will be defined as an injury caused by a foreign object piercing the skin, which damages the underlying tissues and results in an open wound. 7. Prospective participant is currently receiving or is expected to receive any type of renal replacement therapy including hemodialysis or extra corporeal membrane oxygenation, during study period. 8. Prospective participant has a documented diagnosis of diabetes with a serum creatinine (SCR) obtained for clinical care purposes (i.e., SOC results) \>3 mg/dL during screening. 9. Prospective participant has documented severe thyrotoxicosis as noted in medical records during screening. 10. Prospective participant is homozygous for sickle cell disease as noted in medical history/records. 11. Prospective participant has a documented diagnosis of hepatorenal syndrome as noted in medical records during screening. 12. Prospective participant is anuric\* for \>/ = 1 calendar day during screening AND has any one of the following documented conditions as noted in medical history/records: * Pheochromocytoma * Myelomatosis * Multiple myeloma * Paraproteinemia \*Anuria is defined as urine production \<100 mL in a calendar day 13. Prospective participant is pregnant or breastfeeding. 14. Prospective participant received or is expected to receive albumin from one calendar day prior to enrollment to end of study period. 15. Prospective participant received or is expected to receive \>/= 3 units of any blood product other than platelets from one calendar day prior to enrollment to end of study period. 16. Any condition that, in the judgment of the investigator, precludes participation because it could affect the prospective participant's safety.