Urine Albumin-to-Creatinine Ratio
Análisis de orinaÚltima revisión: 7 de abril de 2026. Enfoque de fuentes: contexto estándar de interpretación de laboratorio, material médico de referencia y orientación clínica o de salud pública cuando corresponde.
¿Qué es Urine Albumin-to-Creatinine Ratio?
The urine albumin-to-creatinine ratio (UACR) is a convenient and standardized method for quantifying urinary albumin excretion from a spot (random) urine sample, eliminating the need for a timed 24-hour urine collection. Albumin is a large protein that is normally retained by the glomerular filtration barrier. When the kidneys are damaged, this barrier becomes more permeable, allowing albumin to leak into the urine—a condition known as albuminuria. By dividing the urine albumin concentration by the urine creatinine concentration, the UACR corrects for variations in urine dilution, providing a reliable estimate of daily albumin excretion.
UACR is the recommended test for detecting and monitoring albuminuria, which is a hallmark of diabetic kidney disease and a key marker in the staging of chronic kidney disease (CKD). Current KDIGO guidelines classify albuminuria into three categories: normal to mildly increased (<30 mg/g), moderately increased (30–300 mg/g, formerly called "microalbuminuria"), and severely increased (>300 mg/g, formerly called "macroalbuminuria"). UACR is also an independent cardiovascular risk factor—elevated albuminuria predicts heart attack, stroke, and heart failure even in the absence of overt kidney disease.
Por qué importa
UACR is one of the earliest detectable markers of kidney damage, often appearing years before eGFR begins to decline. In diabetes, persistent moderately increased albuminuria is the first clinical sign of diabetic nephropathy and identifies patients who benefit most from intensified treatment with RAAS inhibitors (ACE inhibitors or ARBs), SGLT2 inhibitors, and tight glycemic control. UACR is also a powerful cardiovascular risk predictor—each doubling of UACR is associated with a 29% increase in cardiovascular mortality. Monitoring UACR allows clinicians to detect kidney damage early, guide treatment decisions, and track response to therapy.
Rangos de referencia normales
| Grupo | Rango | Unidad |
|---|---|---|
| Normal | <30 | mg/g |
| Moderately increased (microalbuminuria) | 30–300 | mg/g |
| Severely increased (macroalbuminuria) | >300 | mg/g |
Los rangos de referencia pueden variar entre laboratorios. Compara siempre tus resultados con los rangos proporcionados por tu laboratorio.
Qué significan los niveles altos de UACR
Causas comunes
- Diabetic nephropathy (most common cause globally)
- Hypertensive nephrosclerosis
- Glomerulonephritis (IgA nephropathy, membranous, focal segmental glomerulosclerosis)
- Lupus nephritis
- Preeclampsia
- Heart failure
- Urinary tract infection (transient elevation)
- Intense exercise or fever (transient elevation)
- Obesity
Posibles síntomas
- Usually asymptomatic in early stages
- Foamy or frothy urine (with significant proteinuria)
- Swelling in feet, ankles, or around eyes (nephrotic range)
- Fatigue
- Elevated blood pressure
Qué hacer: Elevated UACR should be confirmed with at least two of three specimens over 3–6 months, as transient causes (exercise, UTI, fever) can produce false positives. If persistently elevated, evaluate for underlying causes: check blood glucose and HbA1c (diabetes), blood pressure, serum creatinine and eGFR, serum albumin, and urinalysis for active sediment. Treatment focuses on the underlying cause and renoprotective measures: ACE inhibitors or ARBs reduce albuminuria and slow CKD progression, SGLT2 inhibitors provide additional renoprotection, and blood pressure and glycemic targets should be optimized.
Qué significan los niveles bajos de UACR
Causas comunes
- Normal kidney function
- Effective treatment reducing albuminuria
Posibles síntomas
- No symptoms associated with low UACR
Qué hacer: A UACR below 30 mg/g is normal and indicates intact glomerular filtration barrier function. Continue regular screening if risk factors are present (diabetes, hypertension). A reduction in UACR with treatment correlates with improved renal and cardiovascular outcomes.
¿Cuándo se recomienda la prueba de UACR?
- Annual screening in all patients with diabetes (type 1 after 5 years, type 2 at diagnosis)
- Annual screening in patients with hypertension
- Evaluation and staging of chronic kidney disease
- Monitoring response to renoprotective therapy (ACE inhibitor, ARB, SGLT2 inhibitor)
- Cardiovascular risk assessment
- Preeclampsia evaluation in pregnancy
Preguntas frecuentes
Biomarcadores relacionados
Referencias y enfoque de revisión
Las páginas del glosario de biomarcadores son explicaciones educativas y deben interpretarse junto con los rangos de referencia y comentarios proporcionados por tu laboratorio y tu profesional de salud. Para conocer nuestros estándares editoriales y proceso de revisión, consulta nuestra Política editorial y nuestro Proceso de revisión de contenido.
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Subir resultados de laboratorio →Aviso médico: Esta información es solo educativa y no sustituye el consejo, diagnóstico ni tratamiento médico profesional. Los rangos de referencia pueden variar entre laboratorios. Consulta siempre a tu profesional sanitario para interpretar tus resultados concretos.