What correction dose of regular insulin (short‑acting insulin) should be given to an adult with a random blood glucose of 327 mg/dL?

Correction Dose of Regular Insulin for Blood Glucose 327 mg/dL

For an adult with a random blood glucose of 327 mg/dL, administer 2 units of regular insulin as a correction dose if the patient is already on a scheduled basal-bolus insulin regimen. 1

Correction Insulin Dosing Protocol

Simplified Sliding Scale Approach

• For pre-meal glucose >250 mg/dL (13.9 mmol/L): give 2 units of short- or rapid-acting insulin 1
• For pre-meal glucose >350 mg/dL (19.4 mmol/L): give 4 units of short- or rapid-acting insulin 1
• Since 327 mg/dL falls between 250–350 mg/dL, the appropriate correction dose is 2 units of regular insulin 1

Individualized Insulin Sensitivity Factor (ISF) Method

• Calculate ISF using the 1500 Rule for regular insulin: ISF = 1500 ÷ total daily dose (TDD) 2
• Correction dose = (Current glucose − Target glucose) ÷ ISF 2
• Example: If TDD is 50 units and target is 125 mg/dL: ISF = 1500 ÷ 50 = 30 mg/dL per unit; Correction = (327 − 125) ÷ 30 = 6.7 units (round to 7 units) 2

Critical Context: Correction Insulin Is NOT Monotherapy

Sliding-scale insulin as the sole treatment is explicitly condemned by all major diabetes guidelines and should never be used as monotherapy. 1, 2

Why Sliding Scale Alone Fails

• Only 38% of patients on sliding-scale monotherapy achieve mean glucose <140 mg/dL, versus 68% with scheduled basal-bolus therapy 2
• Sliding scale treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations 2
• A glucose of 327 mg/dL signals complete inadequacy of the current insulin regimen, not merely a need for correction dosing 2

Proper Insulin Regimen Structure

• All patients requiring insulin should be on a scheduled regimen with basal, prandial, and correction components 2
• Basal insulin (glargine, detemir, or degludec) provides continuous background coverage 1, 2
• Prandial insulin (regular or rapid-acting) covers meal-related glucose excursions 1, 2
• Correction insulin is administered in addition to scheduled basal and prandial doses, not as a replacement 1, 2

Timing and Administration of Regular Insulin

• Regular insulin should be given 30–45 minutes before meals for optimal postprandial control 2
• Do not give regular insulin at bedtime as a sole correction dose, as this markedly increases nocturnal hypoglycemia risk 1, 2
• For hospitalized patients, correction insulin should be administered subcutaneously every 6 hours using regular insulin 1

When to Escalate Beyond Correction Doses

Immediate Regimen Restructuring Required If:

• Fasting glucose ≥180 mg/dL: increase basal insulin by 4 units every 3 days 2
• Fasting glucose 140–179 mg/dL: increase basal insulin by 2 units every 3 days 2
• Persistent glucose >250 mg/dL: discontinue sliding-scale monotherapy and initiate basal-bolus therapy immediately 2
• Glucose >300 mg/dL with symptoms: check for ketones (urine or blood) and consider diabetic ketoacidosis 1, 2

Basal-Bolus Initiation for Severe Hyperglycemia

• Starting total daily dose: 0.3–0.5 units/kg/day for severe hyperglycemia 1, 2
• Split 50% basal insulin (once daily) and 50% prandial insulin (divided among three meals) 1, 2
• For a 70 kg patient: 21–35 units total daily → 10.5–17.5 units basal + 3.5–5.8 units before each meal 2

Monitoring and Safety

Glucose Monitoring Frequency

• Hospitalized patients eating regular meals: check glucose before each meal and at bedtime 1, 2
• Patients with poor oral intake or NPO: check glucose every 4–6 hours 1, 2
• During insulin titration: daily fasting glucose monitoring is essential 2

Hypoglycemia Management

• Treat any glucose <70 mg/dL immediately with 15 g fast-acting carbohydrate 2
• If hypoglycemia occurs without clear cause, reduce the implicated insulin dose by 10–20% 2

Common Pitfalls to Avoid

• Never rely solely on correction doses when glucose consistently exceeds 250 mg/dL; scheduled insulin must be established 2
• Never delay transition to scheduled insulin when glucose values are consistently >250 mg/dL 2
• Never assume a 2-unit correction is adequate for a glucose of 327 mg/dL if the patient is not on a proper basal-bolus regimen; such dosing indicates fundamental under-dosing 2
• Never continue sliding-scale insulin as monotherapy in patients requiring insulin therapy—this approach is definitively shown to be inferior and dangerous 2

Expected Outcomes with Proper Insulin Therapy

• With appropriate basal-bolus therapy at weight-based dosing, 68% of patients achieve mean glucose <140 mg/dL versus only 38% with sliding scale alone 2
• HbA1c reduction of 2–3% is achievable with proper insulin intensification from current levels 2
• No increased hypoglycemia risk when basal-bolus regimens are properly implemented versus sliding-scale monotherapy 2