Should I recheck the Comprehensive Metabolic Panel (CMP) today for an elderly male patient with mildly elevated glucose and creatinine levels from 3 months ago?

Should You Recheck the CMP Today?

Yes, you should recheck the comprehensive metabolic panel today given that 3 months have elapsed and your elderly male patient has multiple abnormalities requiring monitoring, including Stage 3 CKD (eGFR 59), borderline hyperglycemia (glucose 112 mg/dL), and borderline hypernatremia (Na 147). 1, 2

Key Abnormalities Requiring Follow-up

Your patient's labs show several concerning findings that warrant reassessment:

Chronic Kidney Disease (Stage 3)

• eGFR of 59 mL/min/1.73m² indicates Stage 3 CKD, which requires monitoring of renal function and electrolytes every 4 months in elderly patients with chronic conditions. 2
• The creatinine of 1.22 mg/dL with reduced eGFR necessitates regular surveillance to detect progression. 1, 2
• For elderly patients on any medications metabolized renally or those at risk for acute kidney injury, renal function should be checked at least every 3-6 months. 1

Prediabetes/Impaired Fasting Glucose

• Fasting glucose of 112 mg/dL indicates impaired fasting glucose (prediabetes range: 100-125 mg/dL). 1
• The American Geriatrics Society recommends that elderly patients with abnormal glucose should have repeat testing within 3-6 months to assess for progression to diabetes. 1
• If this glucose was non-fasting, you should obtain a fasting glucose or HbA1c today to properly classify his glycemic status. 1

Borderline Hypernatremia

• Sodium of 147 mmol/L (normal range typically 135-145) suggests mild hypernatremia, which in elderly patients often indicates dehydration or inadequate free water intake. 2
• This requires reassessment as chronic hypernatremia can worsen renal function and increase cardiovascular risk. 2

Recommended Testing Today

Order a complete CMP today along with HbA1c to comprehensively assess:

• Renal function trajectory: Compare current creatinine and eGFR to 3-month-ago values to calculate rate of decline. 1, 2
• Electrolyte status: Reassess sodium, potassium (was borderline low at 3.6), and bicarbonate to ensure stability. 2
• Glycemic control: HbA1c will provide 3-month average glucose control and definitively diagnose or exclude diabetes. 1
• Hepatic function: Recheck transaminases and bilirubin (which was borderline elevated at 1.5 mg/dL). 1

Clinical Reasoning

The 3-month interval is appropriate for several reasons:

• The American Geriatrics Society specifically recommends monitoring renal function and electrolytes every 3-6 months in elderly patients with CKD, particularly those on medications that affect kidney function. 1
• For patients with prediabetes, repeat testing at 3-6 months is standard to determine if progression to diabetes has occurred. 1
• Elderly patients are at higher risk for acute metabolic decompensation, making regular monitoring essential even when stable. 1

Important Caveats

• If your patient is on an ACE inhibitor, ARB, diuretic, metformin, or NSAID, the need for repeat testing is even more urgent given his borderline renal function. 1, 2
• Metformin should be avoided or dose-adjusted if eGFR falls below 45 mL/min/1.73m² and discontinued if below 30. 1, 2
• The borderline low potassium (3.6) combined with CKD warrants close monitoring, especially if he's on diuretics or has heart failure. 2

Ongoing Monitoring Schedule

After today's labs:

• If renal function is stable: Recheck CMP every 4-6 months. 1, 2
• If renal function is declining: Increase frequency to every 1-3 months depending on rate of decline. 1, 2
• If diabetes is diagnosed: Check HbA1c every 6 months if at goal, every 3 months if not at goal. 1