Certified Nephrology Nurse Certification (CNN) Practice Exam 2025 - Free Nephrology Nursing Practice Questions and Study Guide

The primary method for diagnosing chronic kidney disease (CKD) is based on the progressive decrease in glomerular filtration rate (GFR) over time. CKD is characterized by a gradual loss of kidney function, which is reflected in a sustained reduction in GFR. This decrease can be measured through various laboratory tests, but monitoring the GFR is critical for diagnosing and staging CKD.

Over time, the trending of GFR values helps healthcare providers understand the progression of the disease and make informed decisions regarding management. Additionally, CKD is defined as a decrease in kidney function or evidence of kidney damage, lasting for three months or more, which is assessed through consistent measurements of GFR.

While serum creatinine levels can indicate kidney function and may help in estimating GFR, they are not the sole or primary means of diagnosing CKD. Other factors, such as urine output and electrolyte levels, can offer additional insights but do not primarily establish the diagnosis of CKD. Thus, the progressive decrease in GFR is the cornerstone of identifying and understanding chronic kidney disease.