Primary Causes & Action Plans

Creatinine (Serum)

Waste product filtered by kidneys; elevated indicates declining kidney function
Creatinine increases as kidney function declines. However, creatinine can be "normal" even with mild-to-moderate kidney disease in some populations.
Target 0.7-1.3 mg/dL
Suggested Action Plan

If creatinine is elevated, work with doctor on controlling blood pressure, blood sugar, and reducing inflammation. Monitor annually if elevated.

eGFR (Estimated Glomerular Filtration Rate)

More accurate measure of kidney function than creatinine alone
eGFR estimates glomerular filtration rate based on creatinine and demographics. eGFR >60 is considered normal; 30-59 is CKD (chronic kidney disease); <30 is advanced CKD.
Target > 60 mL/min (normal)
Suggested Action Plan

If eGFR declines, focus on blood pressure control, blood sugar control, and inflammation reduction. Recheck annually. Progression requires referral to nephrologist.

Cystatin C

More sensitive marker of early kidney disease than creatinine
Cystatin C is less affected by muscle mass than creatinine and detects early kidney disease more sensitively. Cystatin C >1.0 mg/L suggests some kidney dysfunction.
Target < 1.0 mg/L
Suggested Action Plan

Cystatin C that is elevated despite "normal" creatinine suggests early kidney disease. Investigate and address causes. Retest every 1-2 years if elevated.

BUN (Blood Urea Nitrogen)

Waste product indicating kidney function and protein metabolism
BUN >20 mg/dL suggests declining kidney function. BUN can also be elevated from dehydration or high protein intake.
Target 7-20 mg/dL
Suggested Action Plan

Ensure adequate hydration. If BUN is persistently elevated alongside elevated creatinine/cystatin C, kidney disease is likely. Work with doctor on management.

Uric Acid

Breakdown product of purines; elevated levels increase kidney disease and gout risk
Uric acid is associated with kidney disease and inflammation. Elevated uric acid predicts kidney disease progression and increases cardiovascular risk.
Target < 6.5 mg/dL
Suggested Action Plan

Lower uric acid through reducing purines (red meat, organ meats, alcohol, high-fructose foods). Hydration also helps. If very elevated, allopurinol may be needed.

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Uric Acid Guide
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Getting Started

1
Get Baseline Kidney Function Testing

Test creatinine, eGFR, cystatin C, BUN, and uric acid. If you have risk factors (diabetes, hypertension, family history), establish baseline at age 40-50.

2
Monitor Annual Trends

Annual kidney function testing allows early detection of decline. eGFR decline of >2-3 mL/min/year indicates progression and requires intervention.

3
Control Blood Pressure Aggressively

Hypertension is the primary driver of kidney disease. Target <130/80 mm Hg. Medications (ACE inhibitors or ARBs) are particularly kidney-protective.

4
Control Blood Sugar

Diabetes is the leading cause of kidney disease. Maintain HbA1c below 6.5% through diet and exercise. Metformin and SGLT2 inhibitors are kidney-protective medications.

5
Reduce Inflammation and Adjust Diet

Mediterranean diet, reduced sodium, adequate hydration, and exercise all protect kidney function. If kidney disease is advancing, work with nephrologist on dietary protein restriction.

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"Kidney disease is preventable when caught early. Monitor your kidney function regularly if you have risk factors."

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