What is CKD-U?
The term "CKD-U" does not appear in established nephrology guidelines or medical literature as a recognized clinical entity or diagnostic classification. Based on the provided evidence, there is no standardized definition or clinical framework for "CKD-U" (Chronic Kidney Disease with Urine findings).
Standard CKD Definition and Classification
The established medical definition of chronic kidney disease does not use the "CKD-U" terminology. Instead, CKD is formally defined as:
Kidney damage or GFR <60 mL/min/1.73 m² for 3 months or longer, where kidney damage is defined as pathologic abnormalities or markers of damage, including abnormalities in blood or urine tests or imaging studies 1
CKD is diagnosed by persistent elevation of urinary albumin excretion (albuminuria), low eGFR, or other manifestations of kidney damage for at least 3 months 2
How CKD is Actually Classified
The KDIGO (Kidney Disease: Improving Global Outcomes) classification system stages CKD based on:
GFR categories (G1-G5): Ranging from normal/high (≥90 mL/min/1.73 m²) to kidney failure (<15 mL/min/1.73 m²) 1
Albuminuria categories (A1-A3): Based on albumin-to-creatinine ratio, from normal (<30 mg/g) to severely increased (≥300 mg/g) 1
Cause of kidney disease: The underlying etiology (diabetes, hypertension, glomerulonephritis, etc.) 1
Detection of CKD Through Urine Testing
While "CKD-U" is not a recognized term, urine abnormalities are fundamental to CKD detection:
Both urine albumin measurement and GFR assessment should be used to test people at risk for CKD 1
The most common markers of kidney damage include abnormalities in urine, such as albuminuria (spot urine albumin-creatinine ratio ≥30 mg/g) 1
CKD can be detected using two simple tests: a urine test for albumin and a blood test for serum creatinine to estimate GFR 1
Common Pitfall
The absence of "CKD-U" in medical literature suggests this may be:
- A misinterpretation of standard CKD classification terminology
- A colloquial or regional term not recognized in formal guidelines
- Confusion with the standard practice of detecting CKD through urine abnormalities (albuminuria/proteinuria)
If you encountered "CKD-U" in clinical practice, clarify whether the intended meaning refers to CKD detected by urine abnormalities (albuminuria), which is standard practice, rather than a separate diagnostic category 1.