In a 55‑year‑old man with normal thyroid function, complete blood count, electrolytes, liver enzymes, and calcium, but mildly elevated serum creatinine (1.34 mg/dL, estimated glomerular filtration rate 63 mL/min/1.73 m²), hemoglobin A1c 6.1 % (pre‑diabetes), and positive herpes simplex virus type 2 IgG, what is the interpretation of these laboratory findings and the recommended management?

Laboratory Interpretation and Management

This 55-year-old man has mildly reduced kidney function (Stage 2 CKD), pre-diabetes, and chronic HSV-2 infection—all requiring specific monitoring and lifestyle intervention, but none requiring immediate pharmacologic treatment at this time.

Kidney Function Assessment

The creatinine of 1.34 mg/dL with eGFR 63 mL/min/1.73 m² represents mildly reduced kidney function that warrants further evaluation but is not immediately concerning. 1

• An eGFR of 63 mL/min/1.73 m² places this patient in CKD Stage 2 (GFR 60-89 mL/min/1.73 m²) if kidney damage markers are present, or represents borderline normal function if no damage markers exist 1, 2
• For a 55-year-old, this eGFR is below the threshold typically used for kidney donor acceptance (<90 mL/min/1.73 m²), indicating this is not optimal kidney function for this age 3
• Values of eGFR below 60 mL/min/1.73 m² indicate chronic kidney disease stage 3 and are associated with increased cardiovascular risk, but this patient is just above that threshold 1

Required Follow-Up for Kidney Function

Measure urine albumin-to-creatinine ratio (ACR) on a random urine specimen immediately—this is the principal marker of kidney damage and determines whether CKD is present. 1

• Microalbuminuria (ACR 30-300 mg/g) or proteinuria (>300 mg/g) would confirm kidney damage and establish CKD diagnosis even with eGFR >60 mL/min/1.73 m² 1
• Repeat serum creatinine and eGFR in 3 months to determine if this represents persistent kidney dysfunction, as CKD requires abnormalities persisting ≥3 months 3
• Do not rely on a single eGFR calculation—the confirmatory test should use a different method or be repeated 3
• Serial eGFR measurements over time are more informative than a single value for risk stratification 2

Important Caveats About eGFR

• The MDRD formula may underestimate true GFR in patients with normal to moderately reduced function, though this would mean actual function is better than estimated 2
• Healthy adults can have eGFR values as low as 63.5 mL/min/1.73 m², so values >60 mL/min/1.73 m² overlap with early CKD stages and do not exclude kidney disease 4
• A slight increase in serum creatinine (up to 20%) may occur when antihypertensive therapy is instituted and should not be taken as progressive renal deterioration 1

Pre-Diabetes Management

The hemoglobin A1c of 6.1% indicates pre-diabetes and requires aggressive lifestyle modification to prevent progression to diabetes. 1

• Pre-diabetes is defined as fasting glucose 100-125 mg/dL or HbA1c 5.7-6.4%; this patient's glucose of 96 mg/dL is normal but the HbA1c of 6.1% confirms pre-diabetes 1
• Lifestyle interventions should include weight loss if overweight (target BMI <25 kg/m²), regular physical activity, and dietary modification to reduce cardiovascular risk 1
• Repeat HbA1c in 3-6 months to monitor progression, as undiagnosed diabetes is common and pre-diabetes increases cardiovascular risk independently 1
• The combination of pre-diabetes and borderline kidney function increases cardiovascular risk synergistically 1

HSV-2 Seropositivity

The positive HSV-2 IgG indicates past infection and chronic viral carriage but requires no treatment in the absence of active lesions or frequent recurrences.

• HSV-2 IgG positivity confirms prior exposure and establishes chronic infection status but does not indicate active disease 5, 6
• Suppressive antiviral therapy (valacyclovir 500-1000 mg daily or acyclovir 400 mg twice daily) is indicated only for patients with frequent recurrences (≥6 episodes per year) or for transmission reduction in discordant couples 5, 6
• If suppressive therapy is considered in the future, dosage adjustment is required for eGFR <50 mL/min/1.73 m² for valacyclovir and for creatinine >1.27 mg/dL for acyclovir 5, 6
• Episodic treatment is appropriate for infrequent recurrences, with treatment most effective when started within 48-72 hours of symptom onset 6

Other Laboratory Findings

All other laboratory values are within normal limits and require no intervention:

• Thyroid function (TSH 2.430 μIU/mL, T4 8.1 μg/dL) is normal and excludes thyroid disease as a contributor to symptoms 1
• Complete blood count shows normal hemoglobin (15.2 g/dL), ruling out anemia as a comorbidity 1
• Liver enzymes (AST 16 IU/L, ALT 20 IU/L) are normal, indicating no hepatic dysfunction 1
• Electrolytes (sodium 140 mmol/L, potassium 4.6 mmol/L) are normal and require no adjustment 1

Immediate Action Plan

1. Order urine albumin-to-creatinine ratio today to determine if kidney damage is present 1
2. Counsel on lifestyle modification for pre-diabetes: weight management, exercise, dietary changes 1
3. Repeat creatinine, eGFR, and HbA1c in 3 months to assess for persistence of abnormalities 3
4. If urine ACR is elevated (≥30 mg/g) or eGFR remains <60 mL/min/1.73 m² on repeat testing, refer to nephrology for comprehensive evaluation 3
5. Assess for cardiovascular risk factors including blood pressure measurement, lipid panel if not recently done, and smoking status, as this patient has multiple risk factors 1