Classification of Albumin/Creatinine Ratio of 39.4 mg/g
An albumin/creatinine ratio of 39.4 mg/g is classified as moderately increased albuminuria (formerly called microalbuminuria). 1, 2
Standard Classification Categories
The albumin-to-creatinine ratio is categorized into three distinct levels based on established guidelines 1, 2:
- Normal: <30 mg/g creatinine 1, 2
- Moderately increased albuminuria: 30-299 mg/g creatinine 1, 2
- Severely increased albuminuria: ≥300 mg/g creatinine 1, 2
Your patient's value of 39.4 mg/g falls clearly within the moderately increased range. 1, 2
Confirmation Requirements Before Diagnosis
Do not diagnose albuminuria based on a single measurement. Due to high day-to-day variability (coefficient of variation ~49%), you must confirm this elevation with 2 additional specimens collected over a 3-6 month period before establishing a diagnosis of albuminuria. 1, 2, 3 Two of three specimens must be abnormal (≥30 mg/g) to confirm the diagnosis. 1
Factors That Can Cause False Elevations
Recheck the albumin/creatinine ratio after excluding these transient causes 1, 2:
- Exercise within 24 hours
- Active infection or fever
- Congestive heart failure
- Marked hyperglycemia
- Marked hypertension
- Menstruation (in females)
Clinical Significance and Next Steps
For Diabetic Patients
In youth with diabetes and hypertension, initiate an ACE inhibitor or angiotensin receptor blocker for moderately elevated urinary albumin-to-creatinine ratio (30-299 mg/g). 1 However, avoid these medications in individuals of childbearing age who are not using reliable contraception due to teratogenic effects. 1
For adults with diabetes, this level of albuminuria indicates early diabetic kidney disease and warrants 1, 2:
- Monitoring ACR and eGFR at least annually (or every 6 months if eGFR <60 mL/min/1.73 m²) 2
- Optimization of blood pressure control
- Consideration of renin-angiotensin system blockade
Prognostic Implications
At any level of GFR, increased ACR is associated with higher risk for adverse cardiovascular and renal outcomes, with risk increasing progressively as ACR rises. 2 Even within the moderately increased range, your patient's value of 39.4 mg/g carries continuous risk—higher values within this category predict worse outcomes than lower values. 2
Practical Monitoring Considerations
The albumin/creatinine ratio demonstrates substantial within-individual variability. 3 When monitoring changes over time, a second UACR measurement may range from 0.26 to 3.78 times the initial value due to biological variation alone. 3 If you observe an increase from one measurement to another, obtaining 2 collections at each time point improves confidence that a true change has occurred. 3
For diagnostic purposes (confirming presence/absence of albuminuria), the ranges of diagnostic uncertainty are 2.0-4.0 mg/mmol after a single test, narrowing to 2.4-3.2 mg/mmol with the mean of 2 collections. 3 Multiple collections improve diagnostic accuracy but may not always be necessary for initial diagnosis. 3