Hemoglobin A1c Testing is Indicated
You should order Hemoglobin A1c (Option A) for this patient before proceeding with ankle surgery. 1, 2
Rationale for HbA1c Testing
This patient requires updated assessment of glycemic control because:
- The previous HbA1c of 6.8% was measured "a few months ago" and does not reflect current glycemic status 1
- Current plasma glucose of 155 mg/dL indicates suboptimal control despite dietary modifications and metformin therapy 1
- The American Diabetes Association recommends targeting HbA1c <8% for elective surgeries to reduce surgical risk, mortality, and infection rates 1, 2
- The French Society of Anaesthesia identifies HbA1c >8% as representing preoperative glycemic imbalance that mandates referral to a diabetologist before proceeding with elective surgery 2
Why Current Glycemic Assessment Matters
The elevated fasting glucose (155 mg/dL vs normal 70-99 mg/dL) suggests potential deterioration in glycemic control since the last HbA1c measurement. 1 HbA1c reflects glycemic control over the previous 8-12 weeks and will:
- Distinguish between stress hyperglycemia and worsening diabetes control 1
- Guide perioperative management decisions, including whether surgery should be delayed for optimization 2
- Stratify surgical risk, as suboptimal HbA1c predicts post-operative complications even in diabetic patients 3
Clinical Decision Algorithm Based on HbA1c Result
If HbA1c <8%:
- Proceed with surgery 1, 2
- Hold metformin on day of surgery 1
- Target perioperative glucose 100-180 mg/dL 1
- Monitor glucose every 2-4 hours while NPO 1, 4
If HbA1c ≥8%:
- Delay elective ankle surgery 2
- Refer to endocrinology for treatment intensification 2
- Reschedule surgery only after achieving HbA1c <8% (ideally <7%) 2
Why Other Options Are Incorrect
Prothrombin time/INR (Option B): Not indicated unless the patient is on anticoagulation therapy or has liver disease, neither of which is mentioned. 1
Transthoracic echocardiogram (Option C): Not routinely indicated for ankle surgery in a patient with well-controlled type 2 diabetes without cardiac symptoms. Preoperative cardiac risk assessment is reserved for patients at high risk for ischemic heart disease. 1
High-sensitivity cardiac troponin I (Option D): Not indicated for routine preoperative evaluation in asymptomatic diabetic patients undergoing orthopedic surgery. 1
Critical Perioperative Considerations
- Schedule surgery early in the morning to minimize fasting time 4
- Implement basal-bolus insulin regimens postoperatively rather than correction-only insulin if hyperglycemia persists, as this improves outcomes and reduces complications 1, 2
- Avoid perioperative glucose targets tighter than 100-180 mg/dL, as stricter targets increase hypoglycemia risk without improving outcomes 1