Certified Nephrology Nurse Certification (CNN) Practice Exam 2026 - Free Nephrology Nursing Practice Questions and Study Guide

Dark urine is indicative of possible acute kidney injury (AKI) because it often suggests changes in kidney function and impairs the filtration of waste products from the blood. When the kidneys are not functioning properly due to AKI, they may not filter waste effectively, leading to the buildup of substances like bilirubin in the urine, which can cause a darker color. Additionally, other causes of dark urine, such as hematuria (blood in urine) or concentrated urine due to dehydration, can also signal underlying kidney issues.

In contrast, while loss of appetite can occur in various medical conditions, it is not as specific to AKI as dark urine. Severe headache is also a common symptom but is more commonly associated with other issues like hypertension or neurological problems rather than directly indicating kidney dysfunction. Persistent cough, on the other hand, is usually related to respiratory issues or infections and does not directly indicate AKI.