Comprehensive Workup for Chronic Kidney Disease (CKD)

Initial Diagnostic Testing

• The Kidney International guideline recommends testing for both estimated GFR (eGFR) and albuminuria using urinary albumin-to-creatinine ratio (ACR) as primary markers for CKD diagnosis 1, 2
• The Kidney International guideline suggests using serum creatinine with an estimating equation (eGFRcr) for initial assessment of GFR 1, 2
• If cystatin C is available, the Kidney International guideline recommends using the combination of creatinine and cystatin C (eGFRcr-cys) for more accurate GFR estimation, especially when clinical decisions are significantly impacted 1, 2
• Following detection of elevated ACR, hematuria, or low eGFR, the Kidney International guideline advises repeating tests to confirm the presence of CKD 1, 2

Establishing Chronicity

• The Kidney International guideline states that proof of chronicity (minimum 3 months) can be established by reviewing past GFR measurements/estimations 1, 2
• The Kidney International guideline recommends reviewing past albuminuria/proteinuria measurements and urine microscopic examinations to establish chronicity 1, 2
• Imaging findings showing reduced kidney size or cortical thickness can also be used to establish chronicity, according to the Kidney International guideline 1, 2
• Kidney pathological findings such as fibrosis and atrophy can help establish chronicity, as stated in the Kidney International guideline 1, 2

Determining Cause of CKD

• The Kidney International guideline suggests establishing the cause of CKD using clinical context, personal and family history, social and environmental factors, medications, physical examination, laboratory measures, imaging, and genetic and pathologic diagnosis 1, 2
• The Kidney International guideline recommends considering kidney biopsy when clinically appropriate to evaluate cause and guide treatment decisions 1, 2

Risk Assessment

• The Kidney International guideline advises using externally validated risk equations to estimate the absolute risk of kidney failure in people with CKD G3-G5 3
• The Kidney International guideline suggests considering nephrology referral when 5-year kidney failure risk is 3-5% 3
• A 2-year kidney failure risk >10% can be used to determine timing for multidisciplinary care, according to the Kidney International guideline 3
• Validated models that incorporate eGFR and albuminuria can be used for cardiovascular risk prediction, as stated in the Kidney International guideline 3

Laboratory Evaluation

• A complete blood count can be used to assess for anemia, according to the Journal of the American College of Radiology 4
• A comprehensive metabolic panel including electrolytes, calcium, and phosphorus can be used for laboratory evaluation, as recommended by the Journal of the American College of Radiology 4
• Serum albumin and total protein can be measured as part of laboratory evaluation, according to the Journal of the American College of Radiology 4
• Parathyroid hormone (PTH) levels can be measured in advanced CKD, as stated in the Journal of the American College of Radiology 4
• Vitamin D levels can be measured as part of laboratory evaluation, according to the Journal of the American College of Radiology 4
• Urinalysis with microscopy for casts and epithelial cells can be used for laboratory evaluation, as recommended by the Journal of the American College of Radiology 4
• Urine albumin-to-creatinine ratio can be used as a sensitive and specific marker for CKD, according to the Journal of the American College of Radiology 4

Imaging Studies

• Renal ultrasound can be used to assess kidney size, echogenicity, and structural abnormalities, as recommended by the Journal of the American College of Radiology 4
• CT or MRI can be considered in specific situations, with careful consideration of contrast use, according to the Journal of the American College of Radiology 4
• Iodinated contrast should be used cautiously in patients with CKD due to risk of contrast-induced nephropathy, as stated in the Journal of the American College of Radiology 4
• If gadolinium-based contrast agents are needed for MRI, Group II agents should be used at the lowest diagnostic dose, according to the Journal of the American College of Radiology 4

Management Considerations During Workup

• A comprehensive treatment strategy can be implemented to reduce risks of CKD progression and complications, as recommended by the Kidney International guideline 3

Monitoring and Follow-up

• Lifestyle modifications including physical activity, optimal body weight, and smoking cessation can be encouraged, according to the Kidney International guideline 3

Pitfalls to Avoid

• Chronicity should not be assumed based on a single abnormal eGFR or ACR measurement, as it could result from acute kidney injury, according to the Kidney International guideline 1, 2
• Serum creatinine should not be relied upon solely without calculating eGFR, as this can lead to missed diagnoses, as stated in the Kidney International guideline 1, 2
• The influence of muscle mass, diet, and medications on serum creatinine levels should be considered when interpreting results, according to the Kidney International guideline 1, 2

Chronic Kidney Disease Diagnosis and Management

Diagnostic Testing and Risk Assessment

• The Kidney International guideline recommends obtaining a lipid panel, including total cholesterol, LDL, HDL, and triglycerides, for cardiovascular risk assessment in patients with chronic kidney disease (CKD) 5
• The Kidney International guideline suggests that CKD requires evidence of kidney damage or dysfunction persisting for at least 3 months, and hereditary kidney disease suspected based on family history or clinical presentation should be referred to nephrology 6
• Hematuria with dysmorphic red blood cells or red cell casts indicates glomerulonephritis requiring further serologic workup, according to the Journal of the American College of Radiology 7
• The Kidney International guideline advises avoiding iodinated contrast when possible in patients with eGFR <30 mL/min/1.73m² due to contrast-induced nephropathy risk, and if gadolinium-based MRI contrast is required, use Group II or III agents at the lowest diagnostic dose to minimize nephrogenic systemic fibrosis risk 8
• The Kidney International guideline recommends monitoring for hyperkalemia, especially in patients on RAS inhibitors or with eGFR <30 mL/min/1.73m², and measuring blood pressure at every clinical encounter using standardized technique 9
• The Kidney International guideline suggests starting ACE inhibitor or ARB in patients with albuminuria ≥30 mg/g (A2-A3), regardless of blood pressure, titrating to maximum tolerated dose, and initiating SGLT2 inhibitor in patients with eGFR ≥20 mL/min/1.73m² who have diabetes, ACR ≥200 mg/g, or heart failure 9, 10
• The Kidney International guideline recommends prescribing statin therapy for all patients ≥50 years with CKD, or younger patients with diabetes, prior cardiovascular events, or 10-year cardiovascular risk >10% 5
• The Kidney International guideline advises advising sodium restriction to <2 g/day, recommending protein intake of 0.8 g/kg/day in CKD G3-G5, avoiding high protein intake >1.3 g/kg/day, and encouraging 150 minutes weekly of moderate-intensity physical activity adjusted to cardiovascular tolerance 11

Renal Medication Management in CKD

Introduction to Pillars of Renal Medication Management

• The American Diabetes Association recommends SGLT2 inhibitors for all patients with type 2 diabetes and CKD with eGFR ≥20 mL/min/1.73 m² and urinary albumin ≥200 mg/g creatinine to reduce CKD progression and cardiovascular events 12
• SGLT2 inhibitors provide cardioprotective and renoprotective benefits independent of glucose-lowering effects 12

Pillar 1: SGLT2 Inhibitors

• SGLT2 inhibitors should be temporarily discontinued 48-72 hours before elective surgery to prevent complications, but failure to restart them post-operatively leads to unintentional harm 13, 14, 15

Pillar 2: ACE Inhibitors or ARBs

• The American Diabetes Association strongly recommends ACE inhibitors or ARBs for patients with urinary albumin-to-creatinine ratio ≥300 mg/g creatinine and/or eGFR <60 mL/min/1.73 m², and should be considered for those with modestly elevated albuminuria (30-299 mg/g) 12
• Do not discontinue RAS blockade for minor increases in serum creatinine (≤30%) in the absence of volume depletion 12
• Monitor serum creatinine and potassium levels two weeks after initiation and periodically thereafter 12
• The goal is to achieve a 30% or greater reduction in urinary albumin to slow CKD progression 12
• Blood pressure targets should be <130/80 mmHg, with more aggressive control (<120 mmHg systolic) providing cardioprotective benefits based on SPRINT trial data 16

Pillar 3: Mineralocorticoid Receptor Antagonists

• In patients with CKD who are at increased risk for cardiovascular events or CKD progression, or who cannot use SGLT2 inhibitors, nonsteroidal MRAs (finerenone) are recommended to reduce CKD progression and cardiovascular events 12
• Finerenone provides additional benefit beyond ACE inhibitors/ARBs in reducing albuminuria and cardiovascular risk 12

Pillar 4: Blood Pressure Optimization

• Optimization of blood pressure control and reduction in blood pressure variability are essential to reduce risk or slow CKD progression 12
• Target systolic BP <120 mmHg using standardized office measurement techniques provides cardioprotective and survival benefits 16
• Achieving target BP usually requires multiple antihypertensive agents, including diuretics and calcium channel blockers in addition to RAS inhibitors 16

Medication Safety and Monitoring

• People with CKD are more susceptible to nephrotoxic effects of medications—always weigh benefits versus potential harms 13, 14, 15
• Monitor eGFR, electrolytes, and therapeutic medication levels for drugs with narrow therapeutic windows 13, 14, 15
• Consider GFR when dosing all medications cleared by the kidneys 13, 14, 15
• For most clinical settings, validated eGFR equations using serum creatinine are appropriate for drug dosing 13, 14, 15

Common Pitfalls to Avoid

• Never discontinue all four pillars simultaneously during acute illness without a clear plan for restarting them—this leads to unintentional harm 13, 14, 15
• Do not avoid ACE inhibitors/ARBs due to fear of hyperkalemia or modest creatinine elevation—the benefits far outweigh risks when properly monitored 12
• Avoid NSAIDs and other nephrotoxins that undermine the protective effects of these four pillars 13, 14
• Do not delay SGLT2 inhibitor initiation in eligible patients—early intervention provides maximum benefit 12